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Here we are providing Class 12 Biology Important Extra Questions and Answers Chapter 4 Reproductive Health. Important Questions for Class 12 Biology are the best resource for students which helps in Class 12 board exams.

Class 12 Biology Chapter 4 Important Extra Questions Reproductive Health

Reproductive Health Important Extra Questions Very Short Answer Type

Question 1.
Expand STD and CDRI:
Answer:
STD: Sexually transmitted diseases.
CDRI: Central Drug Research Institute.

Question 2.
Comment on the RCH program of the government to improve the reproductive health of the people:
Answer:
Creating public awareness regarding reproduction-related aspects and providing facilities to build up a healthy society with an added emphasis on the health of mother and child are the basic aims of the RCH programs.

Question 3.
What is the significance of progesterone- estrogen combination as a contraceptive measure?
Answer:
Birth control pills like Mala-D and Saheli are commonly called combined pills as they have progesterone-estrogen combinations. These prevent ovulation from the ovaries. These also retard the entry of sperms in the uterus.

Question 4.
Males in whom testes fail to descend to the scrotum are generally infertile. Why?
Answer:
If the testes fail to descend to the scrotum, gametogenesis could be inhibited as the process of spermatogenesis requires a marginally lesser ambient temperature (2°C less) than that in the abdominal cavity.

Question 5.
Mention one positive and one negative application of amniocentesis. (CBSE 2010)
Answer:

• Positive application: To detect congenital defects or genetic disorders.
• Negative application: Sex determination leads to female foeticide.

Question 6.
Which age group has the highest infection rates of sexually transmitted infections (STIs) including HIV?
Answer:
Young people aged between 15 and 24 years.

Question 7.
Mention any two events that are inhibited by the intake of oral contraceptive pills to prevent pregnancy in humans: (CBSE 2009 (S))
Answer:

1. Inhibition of ovulation.
2. Inhibition of motility and secretory activity of oviducts.

Question 8.
After a successful in vitro fertilization, the fertilized egg begins to divide. Where is this egg transferred before it reaches the 8-cell stage and what is this technique named? (CBSE Sample Paper)
Answer:

1. Fallopian tube.
2. Zygote intrafallopian transfer (ZIFT).

Question 9.
Name two STDs that can be transmitted through contaminated blood. (CBSE 2009 (S))
Answer:

1. AIDS
2. Hepatitis-B.

Question 10.
List the main methods of birth control:
Answer:

1. Mechanical methods
2. Surgical methods
3. Chemical and hormonal methods
4. Natural methods of birth control.

Question 11.
What are the two factors which have raised life expectancy in developing countries?
Answer:

1. The decline in death rate.
2. Increase in longevity.

Question 12.
What are the causes of death of women between ages 15 and 19 years?
Answer:
Complications of pregnancy, childbirth, unsafe abortions.

Reproductive Health Important Extra Questions Short Answer Type

Question 1.
Define reproductive health. How does this affect society?
Answer:
Reproductive health means total well-being in all aspects of reproduction, i.e. physical, emotional, behavioral, and social. A society with people having physically and functionally normal reproductive organs and normal emotional and behavioral interactions among them in all sex-related aspects are called a reproductively healthy society.

Question 2.
What is the significance of reproductive health in a society?
Answer:
A reproductively healthy society survives in a normal way. Reproductive health ensures that all individuals in the reproductive age group are fertile and able to carry on the human race further. Individuals should be educated about reproduction-related aspects like controlled population, absence of sex-abuses, and sex-related crimes in the society and this will enable people to think and take up necessary steps to build up a society that is reproductively healthy.

Question 3.
Is sex education necessary in schools? If so why?
Answer:
Yes, sex education should be encouraged in schools to give the right information to the young minds to save them from myths and misconceptions about sex-related aspects. Proper information about reproductive organs, adolescence and related changes, safe and hygienic sexual practices, sexually transmitted diseases like AIDS, etc. would help people to lead a reproductively healthy life. Thus sex education is necessary to make society reproductively healthy.

Question 4.
What are the suggested reasons for the population explosion?
Answer:
The following are the suggested reasons for population explosion:

1. the rapid decline in death rate.
2. the decline in maternal mortality rate (MMR).
3. the decline in infant mortality rate (IMR).
4. increase in the number of people in reproducible age.

Question 5.
The present population growth rate in India is alarming. Suggest ways to check it.
Answer:

1. Widespread information and materials for birth control.
2. The spread of education facilities.
3. Making young people career conscious.
4. Providing vocational training for gainful employment.
5. Raising marriage age.

Question 6.
Suggest the reproduction-related aspects in which counseling should be provided at the school level.
Answer:
Counseling should be provided to students about reproduction-related problems as:

1. Students are experiencing physical, physiological, and psychological changes during adolescence.
2. Students should be guided about the harms of early sex, hygiene of reproductive organs, and STDs.

Question 7.
Is the use of contraceptives justified? Give reasons.
Answer:
The use of contraceptives is justified because these methods prevent or delay pregnancy and in the long run, help to check the uncontrolled growth of the population and thereby reduce the ill effects of overpopulation on the reproductive health of the society.

Question 8.
Amniocentesis, the fetal sex determination test, is banned in our country. Is it necessary? Comment.
Answer:
Amniocentesis is a fetal sex determination test based upon the chromosomal pattern in the amniotic fluid surrounding the developing embryo. It should be legally banned throughout the country as such a ban shall check increasing female foeticide cases and maintain a normal sex ratio in the country.

Question 9.
Name the hormone composition of oral contraceptives used by a human female. Explain how does it act as a contraceptive? (CBSE 2009)
Answer:

1. Progesterone or progesterone- estrogen combination is used as an oral contraceptive by human females.
2. These pills inhibit ovulation as well as implantation. They also alter the quality of cervical mucus to prevent or retard entry of sperms.

Question 10.
What are the conditions in which medical termination of pregnancy is advised?
Answer:

1. If pregnancy is likely to produce a congenitally malformed child.
2. In case of rape.
3. Contraceptive failure.
4. Pregnancy is likely to harm the mother.

Question 11.
Comment on the essential features required for an ideal contraceptive.
Answer:

1. User friendly, i.e. comfortable and easy to use.
2. Without any side effects.
3. Reversible.
4. Completely effective against pregnancy.

Question 12.
All reproductive tract infections (RTIs) are STDs, but all STDs are not RTIs. Justify with an example:
Answer:
Among the common STDs gonorrhea, syphilis, genital herpes, chlamydiosis, hepatitis-B, AIDS, etc., hepatitis-B and AIDS are not infections of the reproductive organs, though their mode of transmission could be through sexual contact also. All other diseases are transmitted through sexual contact and are also infections of the reproductive tract.

Reproductive Health Important Extra Questions Long Answer Type

Question 1.
Suggest the aspects of reproductive health that need to be given special attention in the present scenario:
Answer:
Conferring upon the demands of the present situation of our country, the following aspects of reproductive health should be given special attention:

1. Control of the human population.
2. Creation of awareness about reproduction-related aspects among people including sex education to the students.
3. Implementation of various action plans to attain reproductive health and building a reproductively healthy society.
4. Continued research on reproduction-related areas.
5. Providing medical assistance and care to people especially during pregnancy, delivery, STDs, abortions, contraception, menstrual problems, infertility, etc.
6. Measures of birth control.

Question 2.
Briefly give an account of various intra-uterine contraceptive (IUD) measures. What are their advantages? How do they function?
Answer:
Different types of lUDs are presently available such as the non-medicated lUDs (e.g. Lippes loop), copper releasing IUDs (CUT, CU 7, Multiload 375), and the hormone-releasing ones (Progestasert, LNG-20). Functions. lUDs increase phagocytosis of sperms within the uterus and the Cu ions released by some suppress sperm motility and the fertilizing capacity of the sperms. The hormone-releasing lUDs, in addition, make the uterus unsuitable for implantation and the cervix hostile to the sperms. Advantages. LEDs are ideal contraceptives for females who want to delay pregnancy and/or space children. It is one of the most widely accepted methods of contraception in India.

Question 3.
What are the measures one has to take to prevent contracting STDs?
Answer:
STDs are sexually transmitted diseases that are transmitted from an infected person to a normal person through sexual intercourse. STDs are a major threat to a healthy society and can be prevented by adopting the following practices:

1. Avoidance of sex with multiple partners.
2. Avoidance of sex with unknown partners.
3. Complete abstinence from sex with infected individuals.
4. Use of condoms during sexual intercourse.
5. In case of doubt, a qualified doctor should be consulted.

Question 4.
People of which age group are more vulnerable to the incidence of infection of STDs? Suggest three ways of preventing STDs.
Answer:
Though all persons are vulnerable to these infections, their incidence is reported to be very high among persons in the age group of 15-24 years.

Preventive measures:

1. Avoid sex with unknown partners/ multiple partners.
2. Always use condoms during coitus.
3. In case of doubt, go to a qualified doctor for early detection and get it completely cured.

Question 5.
Removal of gonads cannot be considered a contraceptive option. Why?
Answer:
Removal of gonads cannot be considered as a contraception option because of the following reasons:

1. It should not have side effects. Gonads also secrete hormones. Thus the other functions will be harmed.
2. It should not interfere with sexual desire.
3. It is an irreversible process. It will lead to infertility.

Question 6.
What are the various oral contraceptives used? How do they function? What is the advantage of Saheli?
Or
Why do some women use ‘Saheli’ pills? (CBSE2009)
Or
Name an oral pill used as a contraceptive by a human female. Explain how does it prevent pregnancy? (CBSE 2011)
Answer:

1. Few oral contraceptives used are Mala D, Saheli, etc.
2. Oral administration of small doses of either progestagens or progestagen- estrogen combinations is another contraceptive method used by females.
3. They are used in the form of tablets and hence are popularly called the ‘pills’.
4. Pills have to be taken daily for a period of 21 days starting preferably within the first five days of the menstrual cycle. After a gap of 7 days (during which menstruation occurs), it has to be repeated in the same pattern till the desired period of contraception.
5. Functions. They inhibit ovulation and implantation as well as alter the quality of cervical mucus to prevent/ retard entry of sperms.
6. Pills are very effective with lesser side effects and are well accepted by females.

Question 7.
A mother of a one-year-old daughter wanted to space her second child. Her doctor suggested Cu-T. Explain its contraceptive actions. (CBSE Delhi 2008)
Or
How does Cu-T act as an effective contraceptive for human females? (CBSE 2009, 2011)
Answer:
Role of Cu-T as the contraceptive:

1. Copper-T increases phagocytosis of spermatozoa within the uterus.
2. Copper ions released also suppress the motility of sperms as well as their fertilizing ability.
3. It is a reversible technique and can be removed as and when required.

Question 8.
Name two hormones that are constituents of contraceptive pills. Why do they have high and effective contraceptive value? Name a commonly prescribed non¬steroidal oral pill: (CBSE Outside Delhi 2016)
Answer:

1. Oral contraceptive pills contain progesterone alone or a combination of progesterone and estrogen hormones.
2. Effective contraceptive pills:
   (a) Inhibition of ovulation
   (b) Inhibition of motility and secretory activity of fallopian tubes.
   (c) Changes in the endometrium layer of the uterus make it unsuitable for implantation.
3. ‘Saheli’ contains a non-steroidal preparation called centchroman.

Question 9.
Suggest some methods to assist infertile couples to have children. (CBSE Delhi 2008 (S) Outside Delhi 2013)
Answer:
There are numerous assisted reproductive technologies (ART) available that can bless infertile couples with children.

They are:

• IVF: In Vitro Fertilisation (Test-tube babies).
• ET: Embryo Transfer
• ZIFT: Zygote Intra Fallopian transfer.
• GIFT: Gamete Intra Fallopian Transfer.
• ICSI: Intracytoplasmic sperm injection.
• IUI: Intrauterine Insemination.

Question 10.
(i) Name any two copper-releasing lUDs:
Answer:
Copper releasing lUDs.
(a) CuT,
(b) Cu7 and
(c) Multiload 375.

(ii) Explain how do they act as effective contraceptives in human females? (CBSE 2014, Sample Paper 2019-20)
Answer:
The action of copper-releasing lUDs.
(a) Increases phagocytosis of sperms within the uterus.
(b) Suppress sperm motility.
(c) Then lUDs also suppress fertilizing capacity of sperms.

Question 11.
Suggest and explain the assisted reproductive techniques which will help a couple to have children, where the female had a blockage in the fallopian tube and the male partner had a low sperm count. (CBSE Sample paper 2018-19) Answer:
1. Since the female partner is having a blockage in the fallopian tube, In Vitro fertilization, followed by embryo transfer (ET) will help her conceive. In this case, sperms from the male partner will be collected and injected into the ovum of the female partner to form a zygote under simulated conditions in the laboratory, and an embryo with more than 8 blastomeres will be transferred into the uterus IUT – intrauterine transfer, to complete its further development.

2. Since the male partner is suffering from low sperm count, and intracytoplasmic sperm injection technique should be used to directly inject sperm into the ovum.

Question 12.
List the objectives of Reproductive and Child Health Care Programmes (RCH):
Answer:
Objectives of RCH are as follows:

1. Creating awareness about various reproduction-related problems.
2. Providing facilities and support for building up a reproductively healthy society.
3. Providing audiovisual and print media support to various government and non-government organizations.
4. Educating the people and providing the right information to save them from myths and misconceptions.
5. Providing proper education regarding reproductive organs, adolescence and related changes, safe and hygienic sexual practices.
6. Providing information regarding the danger of sexually transmitted diseases, AIDS, etc.

Question 13.
Define population. What are the aims of the population study?
Answer:
The population is defined as the total number of individuals of a species present in a particular area. The members of a population have some common characteristics, share a common gene pool, and are capable of interbreeding among themselves to produce fertile offsprings. Aims of Population Study. An alarming rise in the human population has created many serious problems. Therefore, population education has been introduced into the school and college curricula.

Population education is aimed at making the students aware of the:

• consequences of uncontrolled population growth such as environmental pollution, depletion of natural resources, extinction of species, etc ;
• benefits of lowering population growth rate to the biosphere ;
• advantages of a small family to humans ;
• growth, distribution, and density of population ;
• relation of population to the standards of life.

Question 14.
Define birth rate, death rate, and fertility rate.
Answer:
1. Birth or natality rate: It is generally expressed as the number of births per 1,000 individuals of a population per year. It increases the population size (total number of individuals of a population) and population density.

The national average birth rate in India is about 28.6 per 1,000 per year. Among Indian states, Kerala has the lowest birth rate of 18 per 1,000, while U.P. has the highest of 34.8 per 1,000.

2. Death or mortality rate: It is the opposite of the natality rate. It is commonly expressed as the number of deaths per 1,000 individuals of a population per year.

3. Fertility rate: It is the number of live births per unit time per unit number of fertile females. Fertility Rate

Question 15.
What is family planning? List the ways of family planning:
Answer:
Family planning: The main objective of family planning or family welfare program is to prevent the fertilization of the ovum by the male sperm and stop the increase in population growth by various methods, such as contraceptives, intrauterine devices, vasectomy, and tubectomy. The contraceptives (Anirudh) for males and intra-uterine devices, loop for females are used to avoid pregnancy.

Vasectomy is the method of sterilizing males by surgical operation of sperm duct or vas deferens. Tubectomy is the method of sterilizing females by the surgical operation of fallopian tubes. Whatever the method employed, it must take care of the health of the persons concerned.

Because of the family planning methods, the birth rate in India is reduced to some extent. The government gives incentives to those who adopt family planning.

Ways of family planning:

• Late marriage for young persons.
• Increase in the sources of recreation so as to divert the attention from sex.
• The couple should not mate between 8-18th days from the start of the menstrual cycle.
• Use of contraceptives.
• Sterilization.
• Use of drugs.
• Abortion.
• Restrict the family to two children.

Question 16.
Suggest the various measures of population control:
Answer:
Population control: Population explosion can be checked by two methods-population education and birth control.

A. Population education: The knowledge about the relationship of population size and the availability of resources for the welfare of the society is called population education.

1. The students should be convinced about the relationship between overpopulation and unemployment.
2. The citizens should be told how the large size of the population is eating away the resources of the state and the reasons for the limited availability of healthcare, education facilities, and other welfare schemes.
3. People should be made aware of how a large number of children eat away the meager resources of the family with nothing left for bad days, how large families rely on indebtedness to meet emergencies, how child bread earners do not improve the conditions of the family, how uneducated children remain a burden on the society, etc. They should be convinced that a small family can live comfortably even with meager resources.

B. Birth control:

1. Mass media of communication. Radio, television, newspapers, magazines, hoardings, and posters should be employed to spread the message of family planning and birth control and its advantages. The future of mankind depends on the stabilization of the human population at a level that ensures basic necessities of life, employment, and happiness,
2. The law about marriageable age should be widely published and strictly enforced (21 years for boys and 18 years for girls). In developed countries, women marry at the age of 25-35 years.
3. As far as possible, stress should be laid on raising the social status of women. Women having higher social status prefer smaller families. Such women generally marry late.
4. Remove the superstitions and wrong beliefs in the society about a higher number of children being God’s gift connected with earthly or heavenly prosperity.

Question 17.
What is amniocentesis? Write its procedure and significance:
Answer:
Amniocentesis is a fetal sex determination test based upon the chromosomal pattern in the amniotic fluid surrounding the developing embryo. It should be legally banned throughout the country as such a ban shall check increasing female foeticide cases and maintain a normal sex ratio in the country.

Procedure:

1. The fetus bathes in the amniotic fluid that fills the amniotic cavity. At an early stage of pregnancy (14th or 15th week), the location of the fetus and placenta is determined by sonography (use of high-frequency sound waves).
2. Then a small amount of amniotic fluid is drawn by passing a special surgical syringe needle through the abdominal wall and uterine wall into the amniotic sac containing the amniotic fluid.
3. Celts that have sloughed from the fetus’s skin or respiratory tract into the fluid are thus sucked into the syringe.

Significance:

1. These cells can be examined for chromosomal abnormalities, such as Down’s syndrome, Klinefelter’s syndrome, Turner’s syndrome, etc resulting from non-disjunction during cell division.
2. The cells can also be cultured and in about a fortnight enough cells become available for test. The cells and fluid are also tested for metabolic disorders such as phenylketonuria, sickle-cell anemia, etc.

Question 18.
Write a note on test-tube babies: (CBSE 2014)
Answer:
Test-Tube Babies: In some women normal conception is not possible because of blocked oviducts or spermicidal secretions in the vagina or the low sperm count of the husband. In such cases, her ovum is removed, fertilized by her husband’s sperm in a laboratory dish, checked that development has begun, and a morula (up to 32 cell stage) replaced or implanted in her uterus.

The entire operation is carried out under sterilized conditions. With proper medical care, she will give birth to a normal child on the completion of gestation. The baby produced in this manner (conceived out of and nursed in the uterus) is called a test-tube baby. The baby is not reared in the test tube. A scientific term for this procedure is in vitro (“in glass”) fertilization.

The success rate of the technique is less than 20%. To increase the chances of success, the prospective mother is given fertility drugs which cause many ovarian follicles to mature at the same time. This releases many eggs simultaneously, thereby increasing the chances of success.

A developing embryo can be inserted into the uterus of another female, called a surrogate mother, provided her hormones are in the proper phase of the reproductive cycle for implantation to occur.

Question 19.
Correct the following statements:
1. Surgical methods of contraception prevent gamete formation.
Answer:
Surgical methods of contraception block gamete transport and thereby prevent conception.

2. All sexually transmitted diseases are completely curable.
Answer:
Few sexually transmitted diseases are curable if detected at an early stage and some sexually transmitted diseases are not curable, e.g. AIDS.

3. Oral pills are very popular contraceptives among rural women.
Answer:
Oral pills are very popular contraceptives among educated urban women.

4. In E.T. techniques, embryos are always transferred into the uterus.
Answer:
In E.T. techniques, 8-celled embryos may be transferred into the fallopian tubes and more than 8-celled embryos are transferred into the uterus.

Question 20.
Reproductive and Child Healthcare (RCH) programs are currently in operation. One of the major tasks of these programs is to create awareness amongst people about the wide range of reproduction-related aspects. This is important and essential for building a reproductive health society.
1. “Providing sex education in schools is one of the ways to meet this goal.” Give four points in support of your opinion regarding this statement. (CBSE Delhi 2016)
Answer:
Sex education is important in schools:
(a) to provide the right information about myths and misconceptions.
(b) to create awareness about reproduction.
(c) to provide knowledge about the growth of reproductive organs and sexually transmitted diseases (STDs)
(d) to guide the students about social evils such as sex abuse, sex-related crimes, etc.

(ii) List any two indicators that indicate a reproductively healthy society.
Answer:
Indicators about a reproductively healthy society.
(a) Low infant mortality rate (IMR)
(b) Low maternal mortality rate (MMR)

• Increased number of couples with small families.
• Better detection and cure of STDs.

Question 21.
Give a brief account of Assisted Reproductive Technologies (ART). (CBSE Outside Delhi 2013, 2019)
Answer:
Where corrective treatments are not available, there are special techniques called Assisted Reproductive Technologies (ART) to help the couple produce children; they are as follows:
1. Test-Tube baby programs:
(a) In this method, ovum from the wife or a donor female and the sperms from the husband or a donor is allowed to fuse under simulated conditions (as that of the body) in the laboratory; it is called in vitro fertilization (IVF).

2. The zygote or early embryo is transferred into the uterus or fallopian tube for further development; this process is called Embryo Transfer (ET) and can be done in the following ways:
(a) The zygote or embryo up to eight blastomeres is transferred into the fallopian tube; it is called Zygote Intra Fallopian Transfer (ZIFT).
(b) Embryos with more than eight blastomeres are transferred into the uterus. It is called Intrauterine Transfer (IUT).

3. Gamete Intra Fallopian Transfer (GIFT): This method involves the transfer of an ovum collected from a donor female into another female, who cannot produce ova, but can provide suitable conditions for fertilization and further development of the fetus up to parturition.

4. Intra Cytoplasmic Sperm Injection (ICSI): In this method, the sperm is directly injected into the ovum to form an embryo in the laboratory, and then embryo transfer is carried out.

5. Artificial insemination:
(a) In this method, the semen collected from the husband or a healthy donor is artificially introduced into the vagina or into the uterus (intrauterine insemination).
(b) This method is used in cases where infertility is due to the inability of the male partner to inseminate the female or due to very low sperm counts in the ejaculates.

Question 22.
It is commonly observed that parents feel embarrassed to discuss freely with their adolescent children about sexuality and reproduction. The result of this parental inhibition is that the children go astray sometimes.
(i) Explain the reasons that you feel are behind such embarrassment amongst some parents to freely discuss such issues with their growing children.
Answer:
Parents feel embarrassed because of the following reasons:
(a) Indian society is not that broad-minded. So parents feel shy talking openly about these matters to their children.
(b) Improper communication and age gap are the reasons behind such embarrassment.

(ii) By taking one example of a local plant and animal, how would you help these parents to overcome such inhibitions about reproduction and sexuality? (CBSE Delhi 2017)
Answer:
Parents can take the example of China rose to explain the process of sexual reproduction. They can also take an example of the male honeybee and orchid Ophrys flower.

It is evident that sexual attraction is a natural phenomenon. The honeybee is attracted to an Ophrys flower and assumes its one petal as its female partner and pseudo copulate with it. So it is a natural phenomenon and parents should talk regarding this matter to their children.

Question 23.
(a) Explain one application of each one of the following:
(A) Amniocentesis:
Answer:

• Detection of a genetic disorder
• Detection of chromosomal disorder
• Sex determination
• Karyotyping (used for detecting chromosomal aberrations)

(B) Lactational amenorrhea:
Answer:
It is a kind of natural contraception to prevent pregnancy. When the women breastfeed regularly her menstrual cycle stops for some period and thus can’t have a baby.

(C) ZIFT:
Answer:
Application of ZIFT (Zygote Intrafallopian Transfer)- In vitro fertilization, the zygote or early embryos at eight blastomeres stage are transferred to the fallopian tale to complete its further development inside the body of the mother. Hence this method is very helpful for infertile couples.

(b) Prepare a poster for the school program depicting the objectives of the “Reproductive and Child Health Care Programme”. (CBSE Delhi 2019)
Answer:
Reproductive and Child Health Care:

Objectives of RCH:

• Creating awareness about various reproduction-related problems.
• Providing facilities and support for building up a reproductively healthy society.
• Providing audio-visual and print, media support, to various government and non-government organizations.
• Educating the people and providing the right information to save them from myths and misconceptions.
• Providing proper education regarding reproductive organs, adolescence and related changes, safe and hygienic sexual practices.
• Providing information regarding the danger of sexually transmitted diseases, AIDS, etc.
• Awareness regarding that gender selection and detection is punishable.

Example – Hum do hamare do, Beti bachao beti padhao, Do boond zindasi ke etc.

Here we are providing Class 12 Biology Important Extra Questions and Answers Chapter 3 Human Reproduction. Important Questions for Class 12 Biology are the best resource for students which helps in Class 12 board exams.

Class 12 Biology Chapter 3 Important Extra Questions Human Reproduction

Human Reproduction Important Extra Questions Very Short Answer Type

Question 1.
Given below are the events in human reproduction. Write them in correct sequential order? Insemination, gametogenesis, fertilization, parturition, gestation, implantation.
Answer:
Gametogenesis, insemination, fertilization, implantation, gestation, parturition.

Question 2.
The path of sperm transport is given below. Provide the missing steps in blank boxes:

Answer:
A = Vasa efferentia; B = Vas deferens.

Question 3.
What is the role of the cervix in the human female reproductive system?
Answer:
The cavity of the cervix called the cervical canal, and the vagina collectively forms the birth canal for parturition. It also regulates the entry of sperms into the uterus.

Question 4.
Why are menstrual cycles absent during pregnancy?
Answer:
The high levels of progesterone and estrogens during pregnancy suppress the gonadotropins which are essential for the transformation of the primary follicle into Graafian follicle and ovulation.

Question 5.
Give the scientific term for the following:
1. Release of the ovum from the ovary.
2. Onset of the menstrual cycle in females.
3. The structures that pick up ova from the body cavity.
Answer:

1. Ovulation
2. Menarche
3. Fimbriae.

Question 6.
What is the location of Cowper’s glands in the body?
Answer:
Cowper’s glands are situated laterally attached to the urethra beneath the urinary bladder at the base of spongy tissue.

Question 7.
Where are sperms stored in males?
Answer:
They are stored in the epididymis.

Question 8.
What is follicular atresia?
Answer:
Follicles in the ovaries which undergo regression and disappear due to death and disposal by phagocytes during the reproductive years of the female are referred to as follicular atresia.

Question 9.
Which particular part of mammalian sperm secretes enzymes to facilitate penetration of sperm?
Answer:
Acrosome.

Question 10.
Name the hormones involved in the regulation of spermatogenesis.
Answer:
GnRH, LH, FSH, Androgen Binding Protein (ABP), Inhibin, androgens.

Question 11.
How many eggs do you think were released by the ovary of a female dog which gave birth to six puppies? HOTS
Answer:
Six eggs.

Question 12.
What will happen if the fallopian tubes are partially blocked and the ovulated eggs are prevented from reaching the uterus?
Answer:
Fertilization may take place but the zygote may develop in the tube instead of the uterus.

Question 13.
Name the cells which produce testosterone. What is the function of this hormone?
Answer:
Interstitial cells (Leydig’s cells) of testis secrete the testosterone hormone. Function. They control secondary sexual characters.

Question 14.
How does the ovum which is released in the body cavity enter the fallopian tube?
Answer:
Ciliary movements of epithelial cells lining the lumen of nearby fallopian tubes induce the ovum to pass into the open fimbriated funnel-shaped end called ostium.

Question 15.
At what stage of life is oogenesis initiated in a human female? When does the oocyte complete oogenesis? (CBSE Sample Paper)
Answer:
Oogenesis is initiated during the embryonic development stage. It is completed at the time of ovulation.

Question 16.
When do morphogenetic cell movements take place?
Answer:
As blastocyst undergoes gastrulation.

Question 17.
Define spermiogenesis. Where does it occur? (CBSE Delhi 2008 (S))
Answer:
The transformation of non-motile spermatids into motile spermatozoa is called spermiogenesis. It occurs inside seminiferous tubules of testes.

Question 18.
How does colostrum provide initial protection against diseases to newborn infants? Give one reason. (CBSE 2009)
Answer:
The colostrum provides antibodies that are essential to developing resistance for newborn babies.

Human Reproduction Important Extra Questions Short Answer Type

Question 1.
Why scrotal sacs are present outside the body? (CBSE Outside Delhi 2014)
Answer:
The scrotal sac is a pouch of deeply pigmented skin divided into two separate sacs. Each sac contains one testis. The normal temperature of the testes in the scrotum is about 2°C lower than the internal body temperature, the ideal temperature for developing sperms.

Question 2.
Write the location and functions of Sertoli cells in humans? (CBSE 2012, 2014)
Answer:
Sertoli cells. These are present in the seminiferous tubules of the testis. They provide nutrition to germ cells. They play a vital role in the maturation of spermatids into motile sperms.

Question 3.
Name the muscular and glandular layer of the human uterus. Which one of these layers undergoes cyclic changes during the menstrual cycle? Name the hormone essential for the maintenance of this layer. (CBSE 2009)
Answer:

1. Muscular layer – Myometrium
   Glandular layer – Endometrium.
2. Endometrium undergoes cyclic changes during the menstrual cycle.
3. LH hormone maintains the lining of the uterus.

Question 4.
Study the figure given below and answer the questions that follow:

(i) Name the stage of the human embryo the figure represents.
Answer:
Blastocyst (Blastula).

(ii) Identify ‘a’ in the figure and mention its function.
Answer:
Trophoblast

(iii) Mention the fate of the inner cell mass after implantation in the uterus,
Answer:
Inner cell mass gets differentiated as embryo after implantation.

(iv) Where are the stem cells located in this embryo? (CBSE 2009)
Answer:
Stem cells are located in the inner cell mass.

Question 5.
Write two major functions each of testis and ovary?
Answer:
Functions of Testis:

• Production of sperms and
• Secretion of male sex hormones, androgens (e.g. testosterone).

Functions of Ovary:

• Production of ova and
• Secretion of female sex hormones, e.g. estrogens, progesterone.

Question 6.
What is the function of the acrosome and head?
Answer:
Functions of acrosome: It secretes sperm lysins which dissolve the membrane around the egg and thus facilitate the penetration of sperm into the ovum.

The function of the head: Head contains a nucleus that contains hereditary information. The fusion of nuclei is involved during fertilization.

Question 7.
Point out the differences in male and female urethra?
Answer:
In the case of the male urethra, there is a single opening for the elimination of urine and for the ejaculation of sperms. In females, there are two separate openings, one for the elimination of urine and the other is a vaginal orifice. The urethra in males is continued into the penis and in the case of females, it has not been found.

Question 8.
Draw a labeled diagram of a part of the seminiferous tubule showing spermatogenesis. (CBSE Delhi 2010, 2014, Outside Delhi 2019)
Answer:
Section of the testis:

Question 9.
During reproduction, the chromosome number (2n) reduces to half (n) in the gametes and again the original number (2n) is restored in the offspring. What are the processes through which these events take place?
Answer:

1. Chromosome number is reduced to half or (n) during gametogenesis.
2. Restoration of chromosome number to diploid or (2n) stage occurs during fertilization.

Question 10.
What is the significance of ampullary- isthmic junction in the female reproductive tract?
Answer:
The ampullary isthmic junction is the site where fertilization of the ovum takes place.

Question 11.
Draw a labeled diagram of the section through the ovary.
Or
Draw a labeled diagram of a section through the ovary showing various stages of follicles growing in it. (CBSE Delhi 2014, 2019)
Answer:
T.S. of Ovary:

Fig. T.S. of Ovary

Question 12.
Differentiate between Graafian follicle and Corpus luteum.
Answer:

Graafian follicle	Corpus luteum
1. SphericaL or at the sac-Like mass of cells.	1. Large mass of big conicaL yellow cells.
2. Each Graaflan follicle contains a Large, centrally placed ovum surrounded by many Layers of granuLar cells.	2. It is the structure formed after the release of the ovum.
3. Estrogen hormone is secreted.	3. Progesterone hormone is secreted.

Question 13.
Differentiate between spermiogenesis and speciation. (CBSE Outside Delhi 2019)
Answer:
Difference between spermiogenesis and Speramiation: Spermiogenesis is the process of transformation of non-motile spermatids into mature motile sperms (male-gametes) whereas speciation is the release of sperms from Sertoli cells of seminiferous tubules.

Question 14.
Define ooplasm and germinal vesicle.
Answer:

• Ooplasm: The cytoplasm of the haploid ovum is called the ooplasm.
• Germinal vesicle: The nucleus of the ovum at the time of fertilization is termed a germinal vesicle.

Question 15.
Explain the significance of fertilization.
Answer:
Significance of fertilization.

1. The fusion of male and female pronuclei in fertilization restores the diploid number of chromosomes.
2. The activation of secondary oocyte undergoes maturation to form ovum.
3. Fertilization initiates cleavage or segmentation.
4. The combination of the chromatin material from two different parents forms the physical basis of biparental inheritance and variation.

Question 16.
What is the cortical reaction?
Answer:
It is a reaction occurred during fertilization that presents polyspermy, i.e. fusion of multiple sperm with one egg. In this reaction, the cortical granules present beneath the secondary oocyte’s plasma membrane fuse with the plasma membrane and release their contents (enzymes) between the plasma membrane and zona pellucida. These enzymes harden the zona pellucida.

Question 17.
What is a fetus?
Answer:
It is the unborn young one of a viviparous animal after it has taken form in the uterus. In human beings, it represents the product of conception from the end of the eighth week to the moment of birth.

Question 18.
List the characteristics of the morula stage.
Answer:
Characteristics of morula stage:

1. The embryo consists of a solid ball of cells called blastomeres. They are arranged like a mulberry.
2. Morula consists of an outer layer of smaller cells and an inner mass of larger cells.
3. Zona pellucida layer persists during morula.

Question 19.
What is the placenta?
Answer:
It is the structure formed by the union of the fetal and uterine tissue for purpose of nutrition, respiration, and excretion of the embryo. Although the blood vessels of the embryo and the mother come close but are kept separated by some barriers between them. The useful substances pass from maternal blood to fetal blood while the wastes (excretory products and C02) are passed from the fetal blood to maternal blood.

Question 20.
Give the names and functions of the hormones involved in the process of spermatogenesis. Write the names of the endocrine glands from where they are released.
Answer:

Hormone	EndocrIne gland	Functions
(1) FSH	Antenor pituitary	StimuLates Sertoli cells to secrete some factors which help in spermatogenesis.
(2) ICSH/LH	-do-	StimuLates Leydig’s cells of testes to secrete androgens (especially testosterone) which regulate spermatogenesis.

Question 21.
How does colostrum provide initial protection against diseases to newborn infants? Give one reason. (CBSE 2009)
Answer:
The colostrum provides antibodies that are essential to developing resistance for newborn babies.

Question 22.
Diagrammatically shows the development of the human embryo in the female reproductive tract.
Answer:
Events of development:

Fig. Development of the human embryo in the female reproductive tract (Fertilisation-implantation)

Question 23.
When and where do chorionic villi appear in humans? State their function. (CBSE Delhi 2013, 2019)
Answer:

1. After implantation, finger-like projections appear on the trophoblast called chorionic villi. They are surrounded by uterine tissue and maternal blood.
2. The chorionic villi and uterine tissue become interdigitated with each other and jointly form structural and functional units between the developing embryos and maternal bodies called the placenta.

Question 24.
State the fate of the trophoblast of a human blastocyst at the time of implantation and that of the inner cell mass immediately after implantation. (CBSE Outside Delhi 2019)
Answer:
The trophoblast layer of the human blastocyst gets attached to the endometrium and the inner cell mass gets differentiated into an embryo. After attachment, the uterine cells divide rapidly and cover the blastocyst. As a result, the blastocyst becomes embedded in the endometrium of the uterus. It is termed Implantation.

Human Reproduction Important Extra Questions Long Answer Type

Question 1.
Briefly explain the primary male sex organs of man.
Answer:
The testes, male gonads, produce sperms that are suspended outside the abdominal cavity in a sac of skin called the scrotum. It results in maintenance of the temperature of the testis which is lower than the rest of the body. It is a condition favorable to sperm production.

Each testis is an oval-shaped structure and is composed of a large number of seminiferous tubules surrounded by connective tissue in which occurs numerous cells called Interstitial cells or Leydig cells. These cells produce a male sex hormone named testosterone. Seminiferous tubules are lined by a layer of germinal epithelial cells. In between the germinal cells, certain large cells called Sertoli cells are present. They are nutritive in function. The germinal epithelial cells produce sperms by spermatogenesis.

Question 2.
Draw well-labeled sketches of the front view and sagittal section of the male reproductive system of man. (CBSE Delhi 2019)
Answer:
The male reproductive system of man:

Question 3.
Explain the events taking place at the time of fertilization of an ovum in a human female. (CBSE 2010, 2014, (Delhi) 2016)
Answer:
Fertilization is the fusion of two gametic nuclei to form a diploid zygote. It involves a series of chemical and physical steps as follows:

The cortical cytoplasm of the ovum shows the physicochemical reactions called the cortical reactions:

1. Sperm lysins dissolve the membranes around the egg.
2. The Head of sperm containing a nucleus and proximal centriole physically passes into the ovum.
3. Normally these reactions result in the formation of a fertilization membrane outside the egg plasma membrane.
4. Cortical granules burst and release their contents between the egg plasma membrane and zona pellucida, i.e. perivitelline space (no fertilization membrane formation). The plasma membrane shows increased permeability for water, phosphate, and potassium.
5. The electrical potentiality of plasma membrane changes from positive to negative, NAD kinase enzyme becomes activated after fertilization for the oxidation and reduction reaction of the cell.
6. The rate of DNA synthesis increases with great pace after fertilization. Hence the ovum is now ready for mitosis (cleavage).
7. Cleavage results in multicellular individuals.

Question 4.
Give the hormonal control of the male reproductive system. (CBSE Delhi 2009)
Answer:
Hormonal control of the male reproductive system:
1. Hypothalamus: It releases gonadotropin-releasing hormones (GnRH) which bring the release of gonadotropins from the pituitary.

2. Anterior pituitary secretes two gonadotropins:
(a) Follicle Stimulating Hormone (FSH): It stimulates spermato¬genesis in the germ cells of seminiferous tubules of the testis to produce haploid and motile male gametes, called spermatozoa, so is also called games kinetic hormone.

Fig. Hormonal control of the male reproductive system

(b) Interstitial Cells Stimulating Hormone (ICSH): It stimulates interstitial cells to secrete male sex hormone called testosterone.

3. Sertoli cells secrete androgen binding protein (ABP) which concentrates testosterone in the seminiferous tubules.

4. Testosterone hormone secreted by interstitial or Leydig’s cells of testes. It regulates secondary sex organs and secondary sexual characters. It regulates the growth, maintenance, and functioning of secondary sex organs like epididymis, vasa deferentia, prostate gland, seminal vesicles, penis, etc. Testosterone also stimulates the development of mate secondary sexual characters like the appearance of facial hair, deepening of the voice, broadening of shoulders, elongation of bones, and increase in height.

Question 5.
Give an account of the secondary sex organs of a human male. (CBSE Delhi 2011)
Answer:
Secondary Sex OrgAnswer: The tubules meet and join at one end of the seminiferous to form ducts called rete testes that form vasa efferentia leading to the epididymis. It is a narrow tube about 6 m long lying in a coiled mass on the outside of the testis and store sperms. The epididymis in turn leads to the muscular sperm duct, the two sperm ducts open into the top of the urethra, just below the point where it leaves the bladder.

In a short coiled tube, the seminal vesicle branches from each sperm duct just above its opening into the urethra. Reproductive glands. They open into the urethra, the prostate gland, which surrounds it at the point where it leaves the bladder and Cowper’s gland a little lower down.

The urethra in males traverses through the corpus Spongiosum of the penis. Corpora Spongiosum consists of spongy and highly vascular connective tissue containing numerous small spaces that are normally empty but filled with blood when the penis is erect during copulation. The penis becomes erect and firm to facilitate the ejaculation of semen (spermatic fluid) into the vagina of the female.

Question 6.
Differentiate between vasa deferentia and vasa efferentia.
Answer:
Differences between vasa deferentia and vasa efferentia:

Vas deferens	Vasa efferentia
1. Vas deferens is the main duct that carries the sperms from the epididymis to the urethra.	1. They are 10-20 smaLL tubuLes which transfer sperms from rete testes to the epididymis.
2. It conveys mature sperms.	2. It conveys immature sperms.
3. Accessory reproductive glands pour their secretions into it.	3. No secretions are added to it.

Question 7.
Describe the structure of the seminiferous tubule.
Answer:
Each seminiferous tubule is lined by germinal epithelium. The majority of cells in this epithelium are cuboidal spermatogenic cells but a few are large, pyramidal, supporting Sertoli or nurse cells. The cuboidal cells, by mitotic divisions, produce spermatogonia into the lumen of the seminiferous tubule.

The spermatogonia grow into primary spermatocytes, which undergo meiosis, producing haploid cells, first secondary spermatocytes, and then spermatids. The latter metamorphose into spermatozoa. Differentiation of spermatozoa from spermatogonia is called spermatogenesis. The spermatozoa are nourished during development by nurse cells. Mature spermatozoa lie free in the cavity of the seminiferous tubules. Scattered in the connective tissue are Leydig’s cells which secrete a hormone called testosterone.

Question 8.
The mother germ cells are transformed into a mature follicle through series of steps. Provide the missing steps in the blank boxes.

Answer:
A = Primary oocyte; B = Secondary follicle, C = Tertiary follicle.

Question 9.
What is the difference between a primary oocyte and a secondary oocyte?
Answer:

primary oocyte	secondary oocyte
1. It is a diploid structure.	1. It is a haploid structure.
2. It is formed from oogonium through mitosis and differentiation.	2. It is formed from the primary oocyte after it undergoes the first meiotic division.
3. No polar body is formed during its development.	3. A polar body is extruded during its formation.

Question 10.
What is spermiogenesis? List the changes that take place during spermiogenesis.
Answer:
Spermiogenesis. The process of differentiation of motile sperm from the spermatid is called spermiogenesis.

Changes during spermiogenesis:

1. The nucleus becomes compact and forms the head.
2. Distal centriole forms the tail of the sperm.
3. The acrosome is formed at the tip of the head.
4. Mitochondria get arranged in the form of a spiral.
5. The cytoplasm is changed to a sheath.

Question 11.
Draw a mammalian sperm and label its four major parts. (CBSE Delhi 2008, 2011, 2013)
Answer:

Question 12.
Give the functions of the following:
1. corpus luteum
2. endometrium
3. acrosome
4. sperm tail
5. fimbriae.
Answer:
1. Functions of corpus luteum:
(a) It secretes a small amount of estradiol hormone and a significant amount of progesterone.
(b) It also secretes the relaxin hormone.

2. Functions of the endometrium:
(a) It is an internal layer of the uterus. It undergoes cyclic changes during the menstrual cycle.
(b) It provides pits for implantation of the blastocyst.
(c) It takes part in the formation of the placenta.

3. Function of acrosome: It contains hydrolytic enzymes that are used to contact and penetrate the egg at the time of fertilization.

4. Function of sperm tail: It provides motility to the sperm.

5. Function of fimbriae: They help in the collection of ovum after ovulation.

Question 13.
Draw a labeled diagram of the human female reproductive system. (CBSE Delhi 2011, 2013)
Answer:
The female reproductive system of human:

Question 14.
Write a short note on the structure and functions of the vagina.
Answer:
Structure of vagina: The vagina is a muscular tube lined with a membrane. It is composed of a special type of stratified epithelium which is supplied with blood vessels and nerves. It extends from the uterus to the vestibule. The anterior surface of the vagina is in relation to the base of the bladder and urethra. The vagina receives the male sex organ during copulation.

Functions of the vagina:

1. It receives the penis of males during copulation.
2. It serves as the receptacle for the sperms.
3. It acts as a birth canal.

Question 15.
Draw a labeled diagram of the Graafian follicle and ovum. (CBSE 2011, 2012)
Answer:
Graafian follicle:

Question 16.
What is a menstrual cycle? Give an account of a simplified 28-day menstrual cycle. (CBSE 2019 C, Outside Delhi 2019)
Answer:
Menstrual cycle: The cycLic changes that occur in the reproductive organs of primate femaLes (monkeys, apes, and human beings) constitute the menstruaL cycLe. The cycLe of events starts from one menstruation tiLt the onset of the next and Lasts for about 28/29 days (a menses).

Simplified menstrual cycle (28-day Cycle):

Phase	Days	Events
Menstrual phase	1-5	Endometrium breaks down, menstruation begins. The cells of en domain urn, secretions, blood, and the unfertilized ovum constitute the menstrual flow.
Follicular phase (ProLiferative phase)	6-13	Progesterone production is reduced. In fact, menstrual flow is associated with withdrawaL of progesterone.
Ovulatory phase	14	Endometrium rebuilds, FSH secretion, and estrogen secretion increase.
Luteal phase (Secretory phase)	15-28	Both LH and FSH attain a peak level. The concentration of estrogen in the blood is also high and reaches its peak. Ovulation occurs. Corpus luteum secretes progesterone. The endometrium thickens and uterine glands become secretory.

Question 17.
Show with graphic sketch the hormonal control over the menstrual cycle.

Fig. MenstruaL cycLe showing hormonal relations: (A) Gonadotropin, (B) Ovarian cycle, (C) Ovarian hormones, (D) Uterine cycle.

Question 18.
DifferentIate between proliferative and secretory phases.
Answer:
Differences between proliferative and secretory phases:

Proliferative phases	Secretory phases
1. Growth of Graafian follicle and maturation and release of ovum occurs.	1. Prepares the uterus for receiving the fertilized ovum and in case, there is no fertilization, endometrium breaks resulting in bleeding.
2. It is the first phase that follows menstruation.	2. It is the second phase that folLows after the release of an ovum.
3. It starts on the 5th day of menstruaL cycLe and Lasts up to 14 days.	3. It starts after the 14th day when the corpus Luteum is formed.
4. It is caused by estrogen and controLled by FSH.	4. Corpus Luteum is formed under the impact of LH.
5. Contraction of uterine muscLes increases.	5. Contraction of uterine muscles decreases.

Question 19.
1. What is ovulation?
2. What happens to the Graafian follicle after ovulation?
Answer:
1. Ovulation: The release of eggs (at secondary oocyte stage) after rupturing of Graafian follicle is called ovulation.

2. After the ovulation, the granulosa cells as well as the stroma cells from theca Interna rapidly multiply to fill the cavity of the Graafian follicle which becomes the corpus luteum. If fertilization occurs, the corpus luteum grows further and secretes hormone. If fertilization does not take place, the corpus luteum regresses and forms a yellow body.

Question 20.
Differentiate between zona pellucida and corona Radiata.
Answer:
Differences between zona pellucida and corona Radiata:

Zona Pellucida	Corona Radiata
1. The non-ceLLuLar, secretory layer around the ovum is termed zona Pellucidar (or Coleman).	1. The ceLLular layer around zona petLucida is termed Corona Radiata.
2. This Layer is thick and transparent.	2. It is a very thick layer of follicular cells with granular cytoplasm.
3. It encLoses perivitelline space around the pLasma membrane.	3. It does not enclose any space.

Question 21.
Compare mature mammalian sperm and ovum.
Answer:
Similarities:

1. Both are gametes and take part in fertilization,
2. Both are haploid.
3. Both are a carrier of the heredity characters,
4. Both are unicellular structures.

Differences:

Mammalian sperm	Mammalian ovum
1. Sperm is motiLe and encLosed by an only singLe plasma membrane.	1. Ovum Is sphericaL, non-motile, and surrounded by zona pesticide and corona radiate.
2. It is differentiated into four parts, i.e. head, neck, middle piece, and tait.	2. It is a spherical, aLecithaL egg with acentric nucLeus.
3. SmaLL amount of cytopLasm present.	3. A large amount of cytoplasm.
4. Centriotes and acrosome present.	4. CentnoLe and acrosome absent.
5. Mitochondria arranged in the form of a spiral.	5. Mitochondria scattered in the cytoplasm.

Question 22.
Briefly explain the steps of fertilization. (CBSE Delhi 2019)
Answer:
Fertilization is the process of fusion of motile sperm and non-motile ovum which takes place in the fallopian tube (oviduct).

• Fertilization is internal in human females.
• Fertilization is a Physico-chemical process.
• Acrosome in sperm’s head releases enzymes that dissolve the membrane of the egg to facilitate entry of sperm into the ovum.

Steps involved during fertilization:

1. Acrosomal reactions and penetration of sperm.
2. Cortical granule reaction.
3. Formation of pronuclei.
4. The fusion of pronuclei.

Question 23.
In our society, women are often blamed for giving birth to their daughters. Can you explain why this is not correct? (CBSE Delhi 2014)
Answer:
Sex chromosomes determine sex in human beings. In males, there are 44+XY chromosomes, whereas, in females, there are 44+XX chromosomes. Here X and Y chromosomes determine sex in human beings.

Two types of gametes are formed in males, one type is having 50% X-chromosome, whereas another type is having Y-chromosome. In females, gametes are of one type and contain X-chromosome. Thus females are homogametic. If a male gamete having Y-chromosome (endosperm) undergoes fusion with a female gamete having an X-chromosome, the zygote will have an XY chromosome and this gives rise to a male child.

If a male gamete having an X-chromosome (gymnosperm) undergoes fusion with a female gamete having an X-chromosome, the zygote will be having XX-chromosome and this gives rise to a female child.

Question 24.
What is fetal ejection reflex? Explain how it leads to parturition?
Answer:
Fetal ejection reflex is a neuroendocrine mechanism initiated by a fully formed fetus and placenta which helps in parturition.

It operates as below:

1. Foetus secretes hormones from its adrenal glands. These hormones stimulate the posterior pituitary of the mother to release oxytocin.
2. Oxytocin causes forceful contraction of smooth muscles of myometrium called labor pains, which further stimulates more secretion of oxytocin.
3. The stimulatory reflex between uterine contraction and oxytocin secretion continues which causes more forceful contraction of uterine muscles.
4. Uterine contraction pushes the young gradually out through the dilated cervix (caused by relaxin) and vagina.

Question 25.
Give an account of the histology of testis.
Answer:
Each testis is composed of a large number of seminiferous tubules surrounded by connective tissue in which there are numerous cells present called interstitial cells or Leydig cells. The testis is covered by a layer of dense connective tissue called tunica albuginea. From it, various septa radiate inward into the cavity of the testis dividing it into many lobules. The seminiferous tubules are coiled structures.

Each tubule is lined by a layer of germinal epithelial cells. In between the germinal cells, certain large cells called Sertoli cells are present. They are nutritive in function. The germinal epithelial cells give rise to sperms. They are in various stages of development like spermatogonia, primary spermatocytes, secondary spermatocytes, and spermatids. The Leydig cells which lie in connective tissue produce a male sex hormone called testosterone.

Question 26.
Explain the histological structure of the mammalian ovary.
Answer:
The ovary is a female gonad: It produces female sex cells called ova and the female sex hormones. Histologically the ovary is composed of fibrous connective tissue.

Its central part is called the stroma. It contains blood capillaries and nerve fibers. The outer part is called the cortex. A large number of Graafian follicles are embedded in a cortical layer. Each follicle is sac-shaped and contains female germ cells. It develops from the germinal layer. In a sexually mature female, the follicles are all at different stages of development and of different sizes. The cells of follicles are all of different sizes.

The cells of the follicle secrete a hormone called estrogen. In the connective tissue are present corpus luteum. It is formed at the site of a ruptured Graafian follicle. It secretes another hormone called progesterone.

Question 27.
What is spermatogenesis? Briefly describe the process of spermatogenesis.
Or
Give a schematic view of spermatogenesis in humans. (CBSE Delhi 2008, 2010)
Answer:
Spermatogenesis. The process of sperm formation from the sperm mother cells of testis (male gonad) is called spermatogenesis. It is completed in four phases, viz. spermatocytogenesis, meiosis I, meiosis II, and spermiogenesis. Spermatocytogenesis, Meiosis I and Meiosis II. The sperms are formed from the sperm mother cells present in the germinal layer of seminiferous tubules of the testis. Some of the mother cells enlarge to divide mitotically to form spermatogonia.

Growth phase: Some of them enter a period of growth and are called primary spermatocytes which are diploid.

Maturation phase: These cells divide meiotically to form two haploid secondary spermatocytes. Each secondary spermatocyte again divides mitotically. Thus one primary spermatocyte forms haploid spermatids.

Spermiogenesis: These develop into complete spermatozoan. These possess head which is embedded in the nourishing cells called Sertoli cells. The process of conversion of spermatid into spermatozoan is called spermiogenesis or spermine peliosis.

Since each primary spermatocyte divides meiotically to form 4 sperms thus 400 sperms or spermatozoa will be formed from 100 primary spermatocytes. The sperm consists of the acrosome (head), nucleus, and tail.

When sperm production starts, this age is called sexual maturity. It is generally 14-16 years. Spermatogenesis is controlled by the hormone (FSH) of the anterior lobe of the pituitary gland.

Question 28.
What role do pituitary gonadotropins play during the follicular and ovulatory phases of the menstrual cycle? Explain the shifts in steroidal secretions.
Answer:
Gonadotropin-releasing hormone (GnRH) also called gonadotropin-releasing factor (GnRH) is secreted by the hypothalamus of the brain, which stimulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH stimulates the ovarian follicles to produce estrogens during the proliferative phase. LH stimulates the corpus luteum of the ovary to secrete progesterone.

1. The menstrual phase is caused by the reduction of progesterone and estrogens.
2. The proliferative phase is caused by the increased production of estrogens.
3. LH causes ovulation. LH also causes a transformation of the empty Graafian follicle into the corpus luteum by luteinization inside the ovary. LH also stimulates the corpus luteum to secrete progesterone hormone to help in implantation, placentation, and maintenance of pregnancy.
4. A secretory phase is caused by the increased production of progesterone.

Question 29.
A woman has conceived and implantation has occurred. Discuss the sequence of changes up to parturition which will take place within her body under the influence of hormones.
Answer:

1. Under the impact of progesterone and estrogen the size of the uterus and birth canal increases. Relaxation of pelvic ligament takes place. The placenta is developed between chorionic and uterine tissues.
2. Breast size increases to full maturity under the impact of progesterone. Corpus luteum grows in the early month and then regresses in the later month.
3. Menstrual cycle and ovulation do not occur.
4. Uterine changes: Sex hormones, the estrogenic and placental gonadotropins are excreted with urine.
5. The volume of blood increases.

Some of the endocrine glands such as the adrenal cortex, anterior pituitary, and thyroid show enlargement. Relaxin hormone is essential in relaxing the pelvic ligament during parturition.

Oxytocin controls uterine contraction during childbirth.

Question 30.
The zygote passes through several developmental stages till implantation. Describe each stage briefly with suitable diagrams. (CBSE 2010)
Answer:
Cleavage is a holoblastic type but there is a tendency to show size differences of the blastomeres from the very start. Cleavage

Fig. CLeavage in mammalian ovum (pig) Fri sectional view A. zygote; B. two-ceU stage; C. four-cell stage: D. sixteen-celL stage; E. morula stage; F and G. Blastocyst (diagrammatic)

The first cleavage takes place in the cytoplasm of the ovum on an imaginary axis (animal pole to vegetal pole). The first division results in two blastomeres. One blastomere is slightly larger than the other. The larger cell divides first and thus forms the three blastomeres. Then the smaller blastomere divides and thus four blastomeres are formed. It is a 4-celled stage.

2nd cleavage is at a right angle to the 1st cleavage. One member of the large blastomeres of 4-cell stage divides forming 5-cell condition followed by 6-7 stage ultimately 8-celled stage. Successive cleavage divisions result in the formation of the solid mass of cells. The thus solid ball-like stage is called the morula stage.

Conversion of morula into blastula is initiated by dynamic rearrangement of small blastomeres. A central fluid-filled cavity called blastocoel (segmentation cavity) appears. Externally placed blastomeres lose their rounded form and become flat. This trophoblast along with the lining of the uterus forms extra-embryonic membranes. This provides protection and nourishment to the developing embryo.

Fig. Development of a blastodermic vesicle (blastocyst) in pig (diagrammatic sectional view).

Simultaneously zona pellucida disappears and the embryo gets implanted into the uterus. Below the blastodermic vesicle, there appears formative tissue, i.e. inner cell mass. From this inner cell mass, the proper embryo is formed.

Question 31.
Explain the following:
(i) Failure of testes to descend into the scrotum produces sterility.
Answer:
Failure of testes to descend into scrotum is called cryptorchidism. It leads to sterility because the scrotum provides a lower temperature (2°C) than the body temperature necessary for the spermatogenic tissue of testes to produce sperms.

(ii) Spermatids possess a haploid chromosome number.
Answer:
Spermatids possess haploid chromosome numbers because they are produced as a result of spermatogenesis (a kind of reductional or meiotic division). Moreover, it is essential because during fertilization diploid number of chromosomes will be restored in the fertilized egg. The haploid number of chromosomes in the spermatids helps in the maintenance of a specific number of chromosomes in the species.

(iii) The first half of the menstrual cycle is called the proliferative phase as well as the follicular phase.
Answer:
The first half of the menstrual cycle is called the follicular phase because estrogens secreted by the cells of maturing Graafian follicles control the changes in the secondary sex organs. It is also called the proliferative phase because the growth and proliferation of tissue on the wall of the uterus, vagina take place.

(iv) The second half of the menstrual cycle is called the luteal phase as well as the secretory phase.
Answer:
The second half of the menstrual cycle is called the secretory phase as well as a luteal phase because during this phase secretion occurs due to the luteinizing hormone (LH) which stimulates ovulation, the formation of corpus luteum and progesterone.

(v) Primary sex organs control the growth, function, and maintenance of secondary sex organs.
Answer:
Primary sex organs control the growth, function, and maintenance of secondary sex organs because they secrete hormones such as testosterone in males and estrogen and progesterone in females.

(vi) Why are the human testes located outside the abdominal cavity? Name the pouch in which they are present. (CBSE 2014)
Answer:
(a) Testes are located in the scrotal sac (scrotum).
(b) It helps in maintaining the low temperature (2-2.5°C) lower than the normal body temperature required for maturation of sperms.

Question 32.
Describe the formation of three germ layers in a mammalian embryo.
Answer:
The blastodermic vesicle is surrounded by the outer cellular layer (trophectoderm). The blastodermic vesicle shows an internal cluster of cells due to differentiation. This cluster of cells is called inner cell mass. Now the morphogenetic movements (epiboly, emboly, etc.) of the cells in small masses or sheets take place. As a result, three germinal layers (i.e. endoderm, mesoderm, and ectoderm) are formed. Formation of endoderm.

Some cells from the inner cell mass detach. Cells move in sheets or masses in the blastocoel. These are the potential endodermal cells. These cells arrange themselves as second layer inner to the outer layer of a blastodermic vesicle. The blastocoel disappears and a new cavity appears. This new cavity is called archenteron or primitive gut. This archenteron will give rise to the gut tract.

Formation of mesoderm: At the margin of the embryonic disc, cells multiply at an increased rate. The thickness of the embryonic disc increases. These cells detach from the embryonic disc and give rise to the mesoderm.

Formation of ectoderm: After the formation of mesoderm, the cells of the embryonic disc arrange themselves so as to form the ectoderm.

Question 33.
Write functions of the placenta.
Answer:
The placenta serves primarily as an organ that permits the interchange of materials carried in the blood of mother and fetus. Its main functions are:

• Nutrition: Supply of nutrient materials to the fetus.
• Respiration: Supply of 02 to the fetus and receives C02 back from it.
• Excretion: Fluid nitrogenous waste products escape through the placenta.
• Barrier: The placenta is a barrier-like semipermeable membrane.
• Storage: The placenta stores fat, glycogen, and iron for the embryo before the formation of the liver.
• Hormonal function: The placenta secretes extra ovarian hormones estrogen and progesterone in females during pregnancy that serves to maintain the fetus.

Question 34.
Briefly describe the process of oogenesis. (CBSE 2004)
Or
Give a schematic representation of oogenesis in humans. Mention the number of chromosomes at each stage. Correlate the life phases of the individual with the stages of the process. (CBSE (Delhi) 2008, 2009 (S), Outside Delhi 2013)
Or
When and where are primary oocytes formed in a human female? Trace the development of these oocytes till ovulation (in the menstrual cycle). How do gonadotropins influence this developmental process? (CBSE 2010)
Answer:
Oogenesis:
1. The phenomenon of the formation of haploid ova (egg) from the diploid egg mother cell of Ovary (female gonad) is called oogenesis. It occurs in three phases, i.e. multiplication, growth, and maturation.

Fig. Oogenesis

2. One ovum (n) is formed from one primary oocyte (2n) as a result of oogenesis.
3. The oogenesis is also controlled by the FSH hormone.

Question 35.
How does parturition take place? Which hormones are involved in the induction of parturition? (CBSE 2019 C)
Or
‘Parturition is induced by a complex neuroendocrine mechanism’. Justify. (CBSE Sample Paper 2018-2019)
Answer:
The onset of labor is termed parturition. The human gestation period (duration of pregnancy) is normally 280 days from the time of the last menstrual period to the birth of the baby. The process of uterine contractions that expel the baby and placenta is called ‘labor pains’.

It can be divided into three phases. The first stage is dilation, which usually lasts from 2 to 20 hours and ends up with the cervix of the uterus fully open or dilated. The second state, expulsion which lasts from about 2 to 100 minutes begins with full crowning, the appearance of the baby’s head in the cervix and continues while the baby is pushed, head first, down through the vagina into outside where it draws its first breath.

During this phase, placentation which lasts for 10-15 minutes after the birth of the child, the placenta and the fetal membranes are loosened from the lining of the uterus by another series of contractions and expelled. They are collectively called after birth or decidua.

Hormonal control:

• Oxytocin (birth hormone) promotes the contraction of the uterine muscles.
• Relaxin allows the pubic symphysis and ligaments to dilate.
• Corticotropin-releasing hormone (CRH) takes part in the ‘Clock’ that establishes the timing of birth.

Question 36.
A mother is ready to feed her newborn baby just after parturition by nature.
(i) Name the cells which secrete milk.
Answer:
Lacteriferous cells of alveoli of mammary glands. They are present in the breast.

(ii) Name the process of producing the milk.
Answer:
Lactation.

(iii) Name the milk produced during the first few days, after parturition.
Answer:
Colostrum.

(iv) Name the hormone meant for the release of milk.
Answer:
Oxytocin hormone released by the posterior lobe of the pituitary body.

(v) Why the doctors recommend breastfeeding during the initial period of infant growth? (CBSE Delhi 2016)
Answer:
Mother’s milk is low in fat but rich in proteins such as lactalbumin and lactoprotein. Colostrum also contains major immunoglobin IgA. It provides passive immunity to the newborn baby.

Question 37.
Describe the structure of an ovum.
Or
1. Draw a diagram of the structure of a human ovum surrounded by corona Radiata. Label the following parts:
(a) Ovum
(b) Plasma Membrane
(c) Zona Pellucida.
2. State the function of Zona Pellucida. (CBSE Delhi 2013)

Answer:
1. Structure of ovum: Most animaL eggs are spherical or oval, non-motiLe but on close examination, it is noted that one pole is different from the other. The pole from which polar bodies are given off is called an animal pole while the opposite is termed as a vegetal pole. Thus it is said to have polarity. Thus various cytoplasmic substances are distributed along the axis in an unequal manner.

The nucleus also called (germinal vesicle) having a chromatin network is surrounded by the nuclear membrane. It also contains prominent nucleolus. All animal eggs contain some reserve material to provide food called yolk. The cytoplasm of an ovum is called the ooplasm. It lacks a centrosome but contains cortical granules derived from Golgi bodies in its outer region termed cortex.

2. Function of Zona pellucida: During fertilization as a result of the cortical reaction, zona pellucida hardens and prevents the entry of additional sperms (polyspermy).

Question 38.
(i) Explain the following phases in the menstrual cycle of a human female:
(a) Menstrual phase
(b) Follicular phase
(c) Luteal phase
Answer:
Menstrual cycle: The cyclic changes that occur in the reproductive organs of primate femaLes (monkeys, apes, and human beings) constitute the menstruaL cycLe. The cycLe of events starts from one menstruation tiLt the onset of the next and Lasts for about 28/29 days (a menses).

Simplified menstrual cycle (28-day Cycle):

Phase	Days	Events
Menstrual phase	1-5	Endometrium breaks down, menstruation begins. The cells of en domain urn, secretions, blood, and the unfertilized ovum constitute the menstrual flow.
Follicular phase (ProLiferative phase)	6-13	Progesterone production is reduced. In fact, menstrual flow is associated with withdrawaL of progesterone.
Ovulatory phase	14	Endometrium rebuilds, FSH secretion, and estrogen secretion increase.
Luteal phase (Secretory phase)	15-28	Both LH and FSH attain a peak level. The concentration of estrogen in the blood is also high and reaches its peak. Ovulation occurs. Corpus luteum secretes progesterone. The endometrium thickens and uterine glands become secretory.

(ii) A proper understanding of the menstrual cycle can help immensely in family planning. Do you agree with the statement? Provide reasons for your answer. (CBSE Delhi 2017)
Answer:
Yes, a proper understanding of the menstrual cycle can help immensely in family planning. Day 10 to 17 of the menstrual cycle is called the fertile period of a human female. If coitus is done during this period, there is an increased chance of conception. But if coitus abstains during this period, pregnancy can be prevented. Pills used by females are also dependent on the menstrual cycle.

The pills have to be taken daily for a period of 21 days starting preferably within the first five days of the menstrual cycle. It is repeated again after a period of 7 days. These inhibit ovulation and implantation as well.

Question 39.
(i) Explain the menstrual cycle in human females.
Answer:
Menstrual cycle: The cycLic changes that occur in the reproductive organs of primate femaLes (monkeys, apes, and human beings) constitute the menstruaL cycLe. The cycLe of events starts from one menstruation tiLt the onset of the next and Lasts for about 28/29 days (a menses).

(ii) How can the scientific understanding of the menstrual cycle of human females help as a contraceptive measure? (CBSE Delhi 2018)
Answer:
Scientific understanding of the menstrual cycle can be helpful in human females to adopt any contraceptive measure as it can help in demarking the dates during which the chances of contraception are higher. For example, periodical abstinence is one such method in which couples avoid coitus during the 10-17 day of the menstrual cycle when ovulation is expected. Coitus can also be avoided during the time span in which the chances of fertilization are higher if there is a scientific understanding of the menstrual cycle.

Question 40.
(i) Draw a diagram of the adult human female reproductive system and label the different:
(a) parts of the fallopian tube
(b) layers of the uterus wall
Answer:
The female reproductive system of human:

(ii) Explain the events during the fertilization of an ovum in humans. (CBSE Delhi 2018C)
Answer:
When sperm comes in contact with zona pellucida of the ovum, this induces changes in the membrane that blocks the entry of additional sperm.

Thus, it ensures that only one sperm can fertilize an ovum. Secretion of acrosome helps sperm enter into the cytoplasm of the ovum through zona pellucida and plasma membrane. This induces completion of the meiotic division of secondary oocyte and the formation of a haploid ovum and a second polar body. The haploid nucleus of the ovum fuses with the sperm nucleus to form a diploid zygote, i.e. fertilization occurs.

Question 41.
(a) Name the hormones secreted and write their functions:
(i) by corpus luteum and placenta (any two).
Answer:
The Corpus luteum and placenta secrete progesterone. It helps in maintaining the pregnancy as a rising level of progesterone inhibits the release of GnRH which in turn inhibits the production of FSH, LH, and progesterone.

(ii) during the Follicular phase and parturition.
Answer:
FSH is secreted during the follicular phase. It stimulates the growth of the ovarian follicles and also stimulates the formation of estrogen. Relaxin is secreted during parturition. It softens the connective tissue of public symphysis that facilitates parturition.

(b) Name the stages in a human female where:
(i) Corpus luteum and placenta co-exist.
Answer:
The Corpus luteum and placenta co-exist up to blastocyst formation.

(ii) Corpus luteum temporarily ceases to exist. (CBSE (Delhi) 2017)
Answer:
During the menstruation phase corpus luteum ceases to exist.

Very Important Figures:

Here we are providing Business Studies Class 11 Important Extra Questions and Answers Chapter 11 International Business. Business Studies Class 11 Important Questions with Answers are the best resource for students which helps in class 11 board exams.

Class 11 Business Studies Chapter 11 Important Extra Questions International Business

International Business Important Extra Questions Short Answer Type

Question 1.
Explain the importance and advantages of foreign trade.
Answer:
Importance of External Trade: Due to unequal distribution of natural resources and skills of different countries, foreign trade is the only solution to specialise in the production of those goods for which a large number of resources and facilities available in a country and export the surplus production to other countries and simultaneously make imports other goods from some other country.

Foreign trade makes available the goods to the consumers of countries where they are not produced. Thus, it improves the standard of living of the people. Foreign trade is also important for the economic development of a nation. Capital equipment and scarce raw materials can be imported. Similarly, surplus commodities can be exported to other countries and foreign exchange may be earned.

Advantages of Foreign Trade:
The advantages of foreign trade are discussed below –
1. Optimum use of Resources: Foreign trade leads to the international division of labour and specialisation. It reduces wastage of resources resulting from the production of uneconomic goods. The resources are also used efficiently.

2. Standard of Living: International trade helps the people living in different countries to raise their standard of living by providing goods and services which cannot be produced economically in a particular country.

3. International Relations: Foreign trade makes different countries dependent upon each other. A country having surplus products can sell its surplus stock to the deficient countries and a country having a deficiency of a product can import it from another country. This promotes goodwill and cordial relations among the nations of the world.

4. Stabilisation of Prices: Foreign trade leads to stabilisation of prices of commodities throughout the world by adjusting demand and supply. This would not have been possible in the absence of foreign trade.

5. Employment: Foreign trade helps in increasing employment opportunities in the export-oriented industries.

6. Economies of Large-scale: Foreign trade facilitates the specialisation of a country in the production of certain goods. This will help to carry on the production of some commodities not only for home consumption but also for external consumption. This will lead to several economies of large scale production. The resources will also be utilised in a better way.

7. Growth of Economy: Under-developed and developing countries can exploit their unutilised natural resources with the import of technical know-how, machinery and equipment from the advanced countries.

Question 2.
Differentiate between Internal (Home) Trade and Foreign (external) Trade.
Answer:
Difference between Home Trade and Foreign Trade:

Basis	Internal Trade	External Trade
1. Meaning	It means trade conducted within the boundaries of a country.	It means trade between traders of two different countries setting at for from places.
2. Restrictions	There are no restrictions on the volume of the home trade.	There are several restrictions on the volume of foreign trade, e.g., licensing, quota, tariffs, exchange control, etc.
3. Transport	It uses locally available means of transport.	It uses the sea and other modes of transport. Due to long distances, transport cost is higher.
4. Risk	It involves comparatively less risk in transit.	It involves several risks in transit. Sea transport carries more risks compared to surface transport.
5. Foreign Language	There is no problem with foreign language and culture.	The difference between language and social set up of different countries hinder the free flow of trade.
6. Payments	Payments can be made in cash or through cheque. It is easier to collect payments.	Payments are made through banks. The procedure of payment is time-consuming and cumbersome.
7. Currency	Trade is carried in terms of the currency of the country.	Currencies of the two countries are involved. The exchange rate between the two has to be fixed.
8. Laws	National laws, rules and regula¬tions govern the internal trade.	Laws of the respective countries, international law and customs govern the external trade.

Question 3.
Explain the various terms used in foreign trade.
Answer:
Terms used in external trade:
Some of the important terms used in export trade are given below –

1. Free on Board (FOB): The importer has to bear all costs and risks of loss or damage from the port of shipment.
2. Cost and Freight (C&F): Under this contract, the exporter is expected to deliver the goods at the port of shipment. The freight charges are payable by the exporter. The importer bears the risk of loss or damage to the goods after this destination. C&F price consists of the FOB price plus freight charges.
3. Cost, Insurance and Freight (CIF): Under CIF contract, the exporter bears the costs and freight for bringing the goods to the port of destination. It includes charges of insurance against the risks of loss or damage to the goods during transit.

Question 4.
Differentiate between Bill of Lading and Charter Party.
Answer:
The distinction between Bill of Lading and Charter Party:

Points of Distinction	Bill of Lading	Charter Party
1. Receipt	It is a receipt of goods on board the ship.	It is not a receipt of goods.
2. Document of title	It is a document of title to the goods.	It is not a document of title.
3. Transferability	It can be transferred freely by endorsement and delivery.	It cannot be transferred.
4. Lease	It is not a lease of the ship.	It is a lease of the ship.
5. Use	It is used when a part of the ship is to be hired.	It is used when the whole ship is to be hired.
6. Stamp	It requires a 25 paise stamp.	It requires a stamp of higher value.
7. Control	Shipowner always retain control on the ship	Shipowner loses control of the ship for a temporary’ period.
8. Crew	Master and crew remain agents of the shipowner.	Master and crew become agents of the exporter for a temporary’ period.
9. Types	(a) Clean (b) Foul	(a) Voyage charter (b) Time charter
10. Collateral security	It can be used as collateral to borrow money.	It can no he used as a collateral-dl to borrow none’.
11. Clauses and Warranties	Does not mention loading and unloading day and lay days.	Mentions days allowed for loading and unloading and lay days.

Question 5.
Explain the various methods of payment in External Trade.
Answer:
External Trade payment can be made through various methods. The important methods for payment of international trade are as follows:

1. Advance Payment
2. Open Account
3. Documentary Bills
4. Letter of Credit
5. Direct Remittance
6. International Credit Card.

1. Advance Payment: Advance payment means the payment made along with the order by the importer as the exporter is always interested in advance payment of the goods exported. The importer can send payment to the exporter by means of:
(a) Bank Draft.
(b) International Money Order.
(c) Telegraphic/Mail Transfer.
(d) Electronic Transfer.

2. Payment against Open Account: Exporter generally ship the goods and send the shipping documents to the importer and make debit his account for the payment due on goods sent. The importer may make periodic payments against his account. This is convenient for both the exporter and the importer. The exporter is relieved of the botheration of drawing and discounting the bills of exchange. The importer is relieved of the botheration of accepting bills of exchange or getting letters of credit in favour of the exporter.

3. Documentary Bill: The exporter draws a bill of exchange on the importer. The bill may be

• Sight Bill, or
• Usance Bill.

In case of a sight bill, the importer has to make the payment immediately and obtain the shipping documents/ This mode is known as Documents against Payment (D/P). In case of a usance bill, the exporter is given some time to make the payment. However, documents are passed on to him against acceptance of the bill. It is known as Documents against Acceptance (D/A) bill.

The exporter draws a bill of exchange on the importer and attaches to it shipping documents such as a bill of lading, insurance policy, invoice, consular invoice, certificate of origin, and certificate of quality. Such a bill is known as a documentary bill. It is sent through the exporter’s bank which will present it to the importer through his bank or agent. Documentary bills may be of two types:

1. D/A Bill: In case of documents against acceptance, the bank will hand over the shipping documents to the importer when the latter gives acceptance on the bill of exchange.
2. D/P Bill: In case of documents against payment bill, the documents are to be released by the bank only on the payment of the bill either at the time of presentation or within a specified period of time.

4. Letter of Credit: The exporter can request the importer to open a letter of credit with his bank in favour of the exporter. When such an arrangement is made, the importer’s bank will accept the bill of exchange drawn by the exporter under the terms of the letter of credit. After acceptance, the bill is returned to the exporter who can get it discounted with his bank. He can also wait till the period of maturity and instruct his bank to collect payment on its maturity from the importer’s bank.

5. Direct Remittance: Under this method, the exporter sends the goods to the importer and also passes on the shipping documents to him. After receipt of documents, the importer can remit the payment to the exporter through the banking channel or telegraphically. This method involves risk for the exporter as the importer may not send the payment in time.

The modes of direct remittance are as follows –
1. Bank Draft: Bank draft is a popular method of making payment in respect of foreign transactions. A bank draft is issued in favour of the exporter by a commercial bank on receipt of the necessary amount.

In fact, a bank draft is a sort of cheque drawn by a bank on its foreign branch, directing the foreign branch to pay the specified amount of money in a particular currency to the person named in the bank draft. The bank charges a nominal commission for providing this service.

2. Telegraphic Transfer: Under this method, there is a transfer by the telegraph or cable of bank deposits from one country to another. As in case of bank draft, the money is deposited with the importer’s bank which will in return send a telegram to its bank in the exporter’s country to pay a specified amount either to the exporter or his bank.

This method of making the transfer is adopted only when the traders are in a hurry to settle accounts. This method is costlier as compared to other methods. That is why it is not commonly used.

6. International Credit Card: Multinational banks issue international credit cards to importers whose financial position are very sound. They make payment through these cards to the exporter for the goods shipped.

Question 6.
What is special Economic Zones (SEZ’s) Explain their benefits in brief?
Answer:
Special economic zones have been set up with a view to encouraging free trade for the pair of promotion of exports. A special Economic Zone is a duty-free enclave deemed to be foreign territory for the purpose of trade operations and duties and tariff. Goods going to SEZ area shall be treated as “deemed exports.” Goods coming from the SEZ area into DTA (Domestic Tariff Area) shall be treated as imported goods. An SEZ may be set up in the public, private or joint sector or by the state government as notified by the control government.

Special Economic Zones (SEZs) Meaning & Functions: A SEZ is a specifically delineated duty-free enclave and is deemed as a foreign territory for the purposes of trade operations, duties and tariffs. SEZ units may be set up for manufacture of goods and rendering of services, products, processing, assembling, trading, repair, remarking, reconditioning, re-engineering including making of gold/silver/platinum jewellery or tides thereof or in connection therewith.

The EPZs are being converted into SEZs. At present, there are four SEZs in India. The only difference between EPZs and SEZs is that in an EPZ customs permission is necessary for taking the raw material from one place to another, but it is not needed in an SEZ.

The SEZs are not subjected to any predetermined value additions, export-obligations, input/output wastage norms and are treated as outside the customer’s territory.

Under the Export-import (EXIM) Policy 2002-2007, SEZs would get income tax benefits. The advantage would be that the tax concession; would be available for the full tax concession period and not curtailed by the expiry of a notified date as happens now. Currently, income tax concessions for SEZs are for 10 years or 2009-10 whichever is earlier. Offshore banking has been presented in India for the first time.

This will provide units in the SEZ access to funds from abroad at international rates. This means that the cost of funds for the exporters from the SEZs would be less. Exporters in the SEZs wanting to raise ADRs/GDRs also need not go to the US and Europe. Sitting here, they will be able to do so using the overseas banking units (OBUs) set up in the SEZs. Units in the SEZs would be able to get world-class security in their backyard itself without having to go looking for it elsewhere. SEZs in India would become more attractive to foreign investors.

SEZs: described as the “best of our dream projects”: would also benefit in a big way with the government deciding to treat bank branches in these zones as overseas branches free of CRR, SLR and priority sector lending requirements. This would help SEZ units, as well as developers in bringing down the cost of funds as overseas branches of Indian banks, are in a position to lend at much lower rates than those prevailing in the Indian market.

SEZ units will also have the freedom to carry out hedging in commodities, make liberal overseas investments out of their export earnings and borrow overseas without being hindered by existing regulations. Ultimately, this could lead the banking sector to go in for global banking centres which can operate like offshore facilities despite their location on Indian soil.

The new exam policy has given a leg uH to banking sector reforms by permitting Indian banks to set up overseas banking units in SEZs. This means that exporters operating out of the SEZ units and developers would be permitted to hold dollar accounts and the OBUs operating out of the SEZs would be able to deal in multiple currencies. Additionally, through OBUs, exporters in SEZs would have access to financing at international costs.

This is because the OBUs would be exempt from CRR, SLR and priority’ sector lending requirements, which would permit them to operate on par with their overseas branches. Under the new scheme, foreign banks registered in India would also be permitted to set up OBUs in SEZs through the finer details of the scheme would be announced later.

Benefits available to Units in SEZs:

1. They can import goods without payment of duty.
2. Reimbursement of central sales tax.
3. Exemption from payment of central excise duty on all goods eligible for procurement.
4. Reimbursement of central excise duty, if any, paid on bulk-tea procured by SEZ units so long as a levy on bulk tea in this regard is in force.
5. Reimbursement of duty paid on fuels or any other^goods procured from DTA as per the rate of drawback notified by the Directorate General of Foreign Trade from the date of such notification.

Question 7.
Explain the various agreements of WTO.
Answer:
WTO Agreements As against GATT which covered only rules relating to trade in goods, the WTO agreements cover trade in goods, services as well as intellectual property. WTO Agreements make the government responsible to formulate the policies and procedure and make them transparent in order to avoid disputes among the nations. Major WTO agreements are discussed below:

Agreements Forming Part of G ATT: The erstwhile General Agreement on Tariffs and Trade (GATT) after its substantial modification in 1994 (effected as part of the Uruguay Round of negotiations) is very much part of the WTO agreements. Besides the general principles of trade liberalisation, GATT also includes certain special agreements evolved to deal with specific non-tariff barriers. Some of the specific agreements contained in the GATT are listed in the bank on GATT 1994 major agreements.

Agreement on Textile and Clothing (ATC): This agreement was evolved under WTO to phase out the quote restrictions as imposed by the developed countries on exports of textiles and clothing from the developing countries. The developed countries were imposing various ends of quota restrictions under the Multi-Fibre Arrangement (MFA) that itself was a major departure from the GATT’s basic principle of free trade in goods.

Under the ATC, the developed countries agreed to remove quota restrictions in a phased manner during a period of ten years starting from 1995. ATC is considered a landmark achievement of the WTO. It is due to the ATC that the world trade in textile and clothing has become virtually quota-free since 1st January 2005, thus, benefiting immensely the developing countries to expand their textiles and clothing exports.

Agreement on Agriculture (AoA): It is an agreement to ensure free and fair trade in agriculture. Though original GATT rules were applicable to trade in agriculture, these suffered from certain loopholes such as exemption to member countries to use some non-tariff measures such as customs tariffs, import quotas and subsidies to protect interests of the farmers in the home country. Trade-in agriculture became highly distorted especially due to the use of subsidies by some of the developed countries.

AoA is a significant step towards an orderly and fair trade in agricultural products. The developed countries have agreed to lower down the customs duties on their imports and subsidies to the exports of agricultural products. Due to their higher dependence on agriculture, the developing countries have been exempted from making similar reciprocal offers.

General Agreement on Trade in Services (GATS): Agreements are applicable to services also like on goods or merchandise, although services are intangible and cannot be toughed like commodities. GATS is regarded as a landmark achievement of the Uruguay Rbiind as it extends the multilateral rules and disciplines to services. It is because of GATS that the basic rules governing ‘trade in goods’ have become applicable to trade in services.

Three major provisions of GATS governing trade in services are as follows –

• All member countries are required to remove restrictions on trade in services in a phased manner. The developing countries, however, have been given greater freedom to decide about the period by which they would liberalise and also the services they would like to liberalise by that period.
• GATS provides that trade in services is governed by ‘Most Favoured Nations’ (MFN) obligation that prevents countries from discriminating among foreign suppliers and services.
• Each member country shall promptly publish all its relevant laws
  and regulations pertaining to services including international agreements pertaining to trade and services to which member is a signatory.,

Agreement on Trade-Related Aspects of Intellectual Property’ Rights (TRIPS): The WTO’s agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS) was negotiated in 1986-1994. It was the Uruguay Round of GATT negotiations where for the first time the rules relating to intellectual property rights were discussed and introduced as part of the multilateral trading system. Intellectual property means information with commercial values such as ideas, inventions, creative expression and others.

The agreement sets out the minimum standards of protection to be adopted by the parties in respect of seven intellectual properties, viz., copyrights and related rights, trademarks, geographical indication, industrial designs, patents, layout design of integrated circuits, and undisclosed information (trade secrets).

Here we are providing Class 12 Biology Important Extra Questions and Answers Chapter 9 Strategies for Enhancement in Food Production. Important Questions for Class 12 Biology are the best resource for students which helps in Class 12 board exams.

Class 12 Biology Chapter 9 Important Extra Questions Strategies for Enhancement in Food Production

Strategies for Enhancement in Food Production Important Extra Questions Very Short Answer Type

Question 1.
Define the livestock.
Answer:
Domesticated animals reared to provide milk, hide, flesh, etc.

Question 2.
What do you mean by the white revolution?
Answer:
Increased production of milk.

Question 3.
Who is called the Father of the White revolution?
Answer:
Dr. V. Kurien.

Question 4.
Give one example of each of the indigenous and exotic milch breeds of cow.
Answer:
Indigenous breed: Sahiwal; Exotic breed: Brown swiss.

Question 5.
Name one bacterial and one viral disease of cattle.
Answer:
Bacterial disease: Anthrax ;
Viral disease: foot and mouth disease.

Question 6.
What are the main advantages of cross-breeds of fowls over indigenous breeds?
Answer:
These consume less feed and produce more eggs.

Question 7.
Name two high-yielding cross-breeds of fowls.
Answer:
“B-77” and “HH-260”.

Question 8.
What is meant by ‘hidden hunger’?
Answer:
It is the consumption of food that is deficient in some essential nutrients like micronutrients, proteins, and vitamins.

Question 9.
Why are plants obtained by protoplast culture called somatic hybrids?
Answer:
Plants obtained from protoplast culture are called somatic hybrids because they are formed from hybrid cells developed through the fusion of genetically different somatic cells.

Question 10.
A person who is allergic to pulses was advised to take a capsule of Spirulina daily. Give the reasons for the advice.
Answer:
Spirulina is rich in proteins. Thus it overcomes the protein deficiency due to non-eating of pulses.

Question 11.
Give examples of some microorganisms working for SCP.
Answer:
Spirulina maxima, Methylophilus methylotrophs, Candida utilize, Paecilomyces variety.

Question 12.
What is the importance of male sterility in plant breeding?
Answer:
Plant breeders use male-sterile plants in artificial hybridization to avoid self-pollination.

Question 13.
Give the significance of superovulation.
Answer:
It increases the production of eggs (6-8) per cycle. Thus it helps in increasing herd size in a short time.

Question 14.
What is the economic value of Spirulina? (CBSE 2008, 2009)
Answer:
Spirulina can be grown on easily available cheap materials like wastewater from potato processing plants, molasses, and even sewage. They provide a large quantity of protein-rich food. Hence it also minimizes pollution.

Question 15.
List the products obtained from bee-keeping. (CBSE Delhi 2008)
Answer:
Honey, wax, royal jelly, and bee venom.

Question 16.
What is the importance of MOET? (CBSE Delhi 2013)
Answer:
MOET is multiple ovulation embryo transfer technologies.

Importance:

1. It is used to increase herd size in short term.
2. It is also meant for the successful production of hybrids.

Question 17.
Name any two diseases the ‘Himgiri’ variety of wheat is resistant to. (CBSE Outside Delhi 2013)
Answer:

1. Leaf and stripe rust
2. Hill bunt.

Question 18.
Name the following:
(a) The semi-dwarf variety of wheat is high-yielding and disease-resistant.
Answer:

1. Sonalika and
2. Kalyan Sona

(b) Anyone inter-specific hybrid mammal. (CBSE 2012)
Answer:
Mule.

Strategies for Enhancement in Food Production Important Extra Questions Short Answer Type

Question 1.
What is animal breeding? Name two main methods.
Answer:
Animal breeding: The main aim of animal breeding is to produce more milk-yielding cows with longer lactation periods and sturdier work animals. So animal breeding is an important aspect of animal husbandry. Two main methods are inbreeding and outbreeding.

Question 2.
A farmer was facing the problem of low yield from his farm. He was advised to keep a beehive in the vicinity. Why? How would the beehive help in enhancing yield?
Answer:
The honeybee is the major pollinator of several crop plants. Keeping a beehive near the farm will ensure proper pollination of crop plants. Therefore, crop yield will be ensured.

Question 3.
List three scientific approaches to obtain a high yield of crops.
Answer:

1. Crop production management
2. Crop improvement for higher yield through genetic manipulation
3. Crop protection management.

Question 4.
List the main steps of plant breeding. (CBSE2014)
Answer:

1. Collection of variability.
2. Evaluation and selection of parents.
3. Cross-hybridisation among selected parents.
4. Selection and testing of superior recombinations.
5. Testing, release, and commercialization of new cultivars.

Question 5.
Suggest two features of plants that will prevent insect and pest infestation.
Answer:

1. Increasing hair growth on aerial parts of plants.
2. Rendering the flowers nectar less.
3. Enabling plants to secrete insect-killing chemicals (toxins).

Question 6.
Briefly explain hybridization. Give one example.
Answer:
For the process of hybridization, selected parents are crossed to combine useful characters in the progeny. Heterosis is exploited in augmenting yields in several commercial crops. A high-yielding variety of wheat is a classical example of hybridization in crop evolution.

Question 7.
How is a disease-resistant plant selected for successful breeding? (CBSE Delhi 2013)
Answer:
Successful breeding for disease resistance depends mainly on two factors:

1. A good source of resistance.
2. A dependable disease test.

Question 8.
Define germplasm. How is it maintained? (CBSE Delhi 2014)
Answer:
Germplasm is the sum total of all the alleles of the genes present in a crop and its related species. Germplasm collections are usually maintained at low temperatures in the form of seeds. In the case of fruit trees, the germplasm is maintained as trees grown in the field.

Question 9.
Name any five varieties of crop plants that have been developed in India.
Answer:

1. Himgiri variety of wheat.
2. Pusa Swarnim variety of Brassica.
3. Pusa Shubhra variety of Cauliflower.
4. Pusa Komal variety of Cowpea.
5. Pusa Sadabahar variety of Chilli.

Question 10.
What is inbreeding depression and how is it caused in organisms? Write any two advantages of inbreeding. (CBSE Delhi 2011)
Or
Explain inbreeding depression. (CBSE Delhi 2011)
Answer:
Inbreeding depression. Continued inbreeding especially close inbreeding, usually reduces fertility and even productivity. It is termed inbreeding depression.

Advantages of inbreeding:

1. Evolve and maintain a pure line in any animal.
2. It helps in the accumulation of superior genes and the elimination of less desirable genes.

Question 11.
List the four objectives with which bio-fortification has been carried out to improve public health. (CBSE Delhi 2019 C)
Answer:
The method of breeding crops with higher levels of vitamins and minerals or higher protein and healthier fats is called biofortification. It is one of the most important methods for improving public health.

Objective:

• In the recent past, many varieties of crop plants such as rice, carrots, spinach, pumpkin, and bathua have been developed which possess several times more nutritive value and vitamins as compared to existing varieties.
• High protein content and quality
• High oil content and quality
• Micronutrient and minerals content.

Question 12.
Why is animal husbandry essential?
Or
What are the objectives of animal breeding? (CBSE 2014)
Answer:

• To increase milk production.
• To increase egg production.
• To increase meat production.
• To increase fish production.
• For proper utilization of animal wastes.

Question 13.
(a) What is the breeding of crops for enhancing their nutritional value called? Why is the need felt for enhancing the nutritional value of the crops?
Or
How have these grains improved in their nutritional value in comparison to their conventional varieties? (CBSE Outside Delhi 2019)
Answer:
Iron-fortified rice variety contains over five times as much iron as compared to commonly consumed rice.

(b) Rice, wheat, and maize are the most commonly used food grains the world over.
Answer:

1. Iron-fortified rice variety contains over five times as much iron as compared to commonly consumed rice.
2. Wheat variety Atlas-66 has huge protein content.
3. Maize hybrids have twice the amount of lysine and tryptophan amino acid.

Question 14.
Name any two common Indian millet crops. State one characteristic of millets that has been improved as a result of hybrid breeding to produce high-yielding millet crops. (CBSE Delhi 2015)
Answer:
Hybrid varieties of maize, Jower, and Bajra have been developed in India by plant breeders. Hybrid breeding has led to the development of several high-yielding varieties resistant to water stress.

Question 15.
Enumerate four objectives for improving the nutritional quality of different crops for the health benefits of the human population by the process of “Biofortification.” (CBSE Delhi 2015)
Answer:
Objectives:

• Protein content and quality.
• Oil content and quality.
• Vitamin content.
• Micronutrient and mineral content.

Question 16.
(i) Why are the plants raised through
micropropagation termed as some clones 1(CBSE Outside Delhi 2015)
Answer:
Plants raised by the tissue culture method are genetically identical to the original plant from which they were grown hence called some clones.

(ii) Mention two advantages of their technique.
Answer:
(a) Plants can be produced on a commercial scale.
(b) Recovery of healthy plants from diseased plants.

Question 17.
(i) Name any two fowls other than chicken reared in a poultry farm.
Answer:
Fowls other than chickens :

1. Turkeys,
2. Geese,
3. Swans,
4. Guinea fowls,
5. Peafowls.

(ii) Enlist four important components of poultry farm management. (CBSE Delhi 2016)
Answer:
Important components of poultry farm management:
(a) Selection of disease-free and suitable breeds.
(b) Brood house should be crowd-free.
(c) Sanitation and hygiene. The brooding house should be cleaned, disinfected, and with the proper drainage system.
(d) Care of chicken during brooding.

Question 18.
Explain the process of artificial hybridization to get improved crop variety in
(i) plants bearing bisexual flowers and
Answer:
In plants bearing bisexual flowers, the anthers are removed from the flower before they dehisce. This is called emasculation. The emasculated flowers are covered with a bag of butter paper to prevent contamination of stigma with unwanted pollen. This process is called bagging. When this stigma attains receptivity, mature pollen grains are dusted on the stigma and the flowers are rebagged to allow the fruits to develop.

(ii) female parent producing unisexual flowers. (CBSE Outside Delhi 2010)
Answer:
If the female parent produces unisexual flowers, emasculation is not done. The flower buds are bagged before the flowers open. When the stigma becomes receptive, pollen is dusted on the stigma and the flower is rebagged.

Question 19.
(i) Mention the property that enables the explants to regenerate into a new plant.
Answer:
Totipotency is the ability of a cell to grow or generate the whole plant.

(ii) A banana herb is virus-infected. Describe the method that will help in obtaining healthy banana plants from this diseased plant. (CBSE Outside Delhi 2010, Delhi 2019)
Answer:
Healthy banana plants can be obtained from diseased plants by meristem culture. Although the plant is virus-infected, the apical and axillary meristems are free of virus. The meristem is removed from the plant and is grown in vitro by micropropagation. The plants produced are virus-free.

Question 20.
You have obtained a high-yielding variety of tomatoes. Name and explain the procedure that ensures retention of the desired characteristics repeatedly in large populations of future generations of the tomato crop. (CBSE Delhi 2018)
Answer:
The retention of the desired characteristics in a large population of crops can be done by micropropagation, which is a type of vegetative propagation.

In this process, a small part of the plant is excised and grown under a sterile condition in a special nutrient medium to obtain many such plants that would be genetically identical to the original plants.

Question 21.
A herd of cattle is showing reduced fertility and productivity. Provide one reason and one suggestion to overcome this problem. (CBSE Delhi 2017)
Answer:
The cattle’s productivity is decreased due to inbreeding depression. A single outcross, i.e. breeding with animals of the same breed but should not have a common ancestor on either side up to 4-6 generations, can restore its fertility.

Question 22.
Why are microbes like Spirulina being produced on a commercial scale? Mention its two advantages. (CBSE Delhi 2018C)
Answer:
25% of the human population suffers from hunger and malnutrition. Single-cell protein (SCP) is the solution to this problem. Spirulina is a rich source of protein, so it is grown on a commercial scale for SCP production.

Advantages:

1. It utilizes cheap substrate like raw material like animal manure, wastewater from potato processing plants, straw molasses, and even sewage, therefore incidentally cleaning the environment and reducing pollution.
2. A small amount of microbe can produce a huge quantity of protein.

Question 23.
“Modern methods of breeding animals and plants can alleviate the global food shortage”. Comment on the statement and give suitable examples.
Answer:
Several new techniques like inbreeding, outbreeding, artificial insemination, MOET, somatic hybridization, and tissue culture are playing important role in enhancing global food production. Because all these techniques aim at increasing productivity.

Strategies for Enhancement in Food Production Important Extra Questions  Long Answer Type

Question 1.
What is apiculture? How is it important in our lives? (CBSE Delhi 2019 C)
Or
Beekeeping practice is a good income-generating industry. Write the different points to be kept in mind for successful beekeeping. Write the scientific name of the most common Indian species used for the purpose. (CBSE Delhi 2019)
Answer:
Apiculture is the maintenance of hives of honeybees for commercial purposes. It is also called Beekeeping. Apiculture is very important in our lives because it produces products of high economic and nutritive value:

1. The main product of beekeeping is honey which is a highly nutritious edible product. It replaces the use of sugar in many industries.
2. Honey is used as a part of many indigenous medicines.
3. Another product called beeswax is also produced which is used in the cosmetic and polish industry.
4. Honeybees are chief pollinating agents so helpful in improving the plant yield.
5. The most commonly used species in the wild state is Apis Indica and in the domestic state Apis mellifera.

Question 2.
What is plant breeding? (CBSE Delhi 2013)
Answer:
Plant breeding is the genetic improvement of the crop in order to create desired plant types that are better suited for cultivation, give better yields, and are disease resistant. Conventional plant breeding is in practice from 9,000 to 11,000 years ago. Most of our major food crops are derived from domesticated varieties.

But now due to advancements in genetics, molecular biology, and tissue culture, plant breeding is being carried out by using molecular genetic tools. Classical plant breeding includes hybridization (crossing) of pure lines, artificial selection to produce plants with desirable characters of higher yield, nutrition, and resistance to diseases.

Question 3.
What is a hybrid? Explain the procedure of obtaining a hybrid.
Answer:
Hybrid: A progeny obtained by crossing two varieties or species having desired genes thus showing required characters.

Process of hybridization:
This technique involves the following steps:

1. Removal of undehisced anthers from the bisexual flower of a plant to be used as female. This is called emasculation.
2. The emasculated flowers are covered by butter paper to avoid pollination by an undesirable pollen grain. It is also termed bagging.
3. Pollen grains from known seeds of desirable plants are used to pollinate these emasculated flowers.
4. They are collected, multiplied and their desirable characters are determined.

Question 4.
(i) Give the scientific name of the soil bacterium which produces crystal (Cry) proteins.
Answer:
A soil bacterium Bacillus thuringiensis (Bt) produces a crystal (Cry) protein.

(ii) How are these proteins useful in agriculture?
Answer:
A crop expressing cry gene is usually resistant to a group of insects for which the concerned Cry protein is toxic.

(iii)What do the different written terms “Cry” and “cry” represent respectively?
Answer:
The first letter of the protein symbol is always capital and always written in roman letters, i.e. Cry. However, the gene symbol usually has small letters and written in italics, i.e. cry. So Cry represents protein and cry represents a gene.

Question 5.
Differentiate between inbreeding and outbreeding in cattle. State one advantage and one disadvantage for each one of them. (CBSE Delhi 2013)
Or
How is inbreeding advantageous as well as disadvantageous in cattle breeding programs? (Mention any two advantages and two disadvantages.) (CBSE Sample Paper 2019-20)
Answer:
Differences between inbreeding and outbreeding:

Inbreeding	Outbreeding
1. Breeding between animals of the same breed for 4-6 generations.	1. Breeding between unrelated animats.
2. Continuous inbreeding leads to inbreeding depression, i.e. reduced fertility and productivity.	2. It leads to heterosis or hybrid vigor.
3. Advantages of inbreeding: It helps in restoring fertility and yield.	3. Advantage of outbreeding: It causes hybrid vigor.
4. Disadvantages of inbreeding: Continued inbreeding reduces fertility and even productivity. It is called inbreeding depression.	4. Disadvantage of outbreeding: It is costly and a difficult procedure.

Question 6.
What are superovulation and embryo transfer?
Or
Explain the strategy used for herd improvement in cattle. (CBSE Delhi 2019 C)
Or
Expand MOET. Explain the procedure of this technology in cattle improvement. (CBSE Delhi 2008, 2012, Outside Delhi 2019)
Answer:
MOET (Multiple Ovulation and Embryo Transplantation Technique). It is the latest technique to produce super milch cows.

1. Superovulation: It involves the stimulation of high milk-producing cows to ovulate more eggs by hormonal stimulation. Fertilization is done by artificial insemination. In this way, 4 to 10 embryos are developed in such cows.
2. Embryo transfer: In this, embryos are collected from superovulated cows. Each embryo is transplanted in the uterus of surrogate cows of inferior quality to produce a large number of calves with good germplasm. It can also be done in sheep, goats, and other livestock animals as well.

Question 7.
Why does a beekeeper keep beehives in crop fields during the flowering periods? State any two advantages. (CBSE Sample Paper)
Or
Honey collection improves when beehives are kept in crop fields during the flowering season. Explain. (CBSE 2010)
Answer:

1. Bees act as pollinating agents.
2. Bees bring about cross-pollination. Thus the productivity of crops increases. This in turn is beneficial to bees too as they get nectar to make honey.

Question 8.
Give a brief account of the cultivation of sugarcane and millets. (CBSE Delhi 2011, 2015)
Or
Write the scientific name of the sugarcane variety that was originally grown in North India. Why was this variety hybridized with the tropical variety of sugarcane grown in South India? (CBSE Delhi 2019 C)
Answer:
Cultivation of sugarcane:

1. Saccharum Barberi, originally grown in North India, had poor sugar content.
2. Saccharum officinarum, grown in South India, has thicker stems and higher sugar content but could not grow properly in North India.
3. A cross has been made between these species and the hybrid variety, combining the desirable qualities like thick stem, high sugar content, and higher yield is being grown in North India.

Cultivation of millets:

1. Several hybrid varieties of maize, bajra, and Jowar have been developed in India.
2. These breeding programs have resulted in the development of high-yielding varieties that are resistant to water stress.

Question 9.
Explain out-breeding, out-crossing, and cross-breeding practices in animal husbandry. (CBSE Delhi 2018)
Or
Differentiate between out-crossing and cross breeding. (CBSE Delhi 2018C)
Answer:
Out-breeding: Out-breeding is the breeding of unrelated animals, which may be between individuals of the same breed but having no common ancestors for 4-6 generations or between different breeds or different species.

Out-crossing: Out-crossing is the practice of mating animals within the same breed, but having no common ancestors on either side of their pedigree, up to 4-6 generations. It is the best breeding method for animals that are below average in milk productivity.

Cross-breeding: Cross-breeding allows the desirable qualities of two different breeds to be combined. In this method, superior males of one breed are mated with superior females of another breed. The progeny hybrid animals may be used for commercial production or they may be subjected to some form of inbreeding and selection to develop new stable breeds that may be superior to the existing breeds. Many new animal breeds have been developed by this approach.

Question 10.
(i) Write the desirable characters a farmer looks for in his sugarcane crop,
Answer:
The desirable characters that should be present in the sugarcane crop are:
(a) High yield,
(b) thick stem,
(c) high sugar content and
(d) ability to grow in North India.

(ii) How did plant breeding techniques help north Indian farmers to develop cane with desired characters? (CBSE Delhi 2017)
Answer:
Cultivation of sugarcane:

1. Saccharum Barberi, originally grown in North India, had poor sugar content.
2. Saccharum officinarum, grown in South India, has thicker stems and higher sugar content but could not grow properly in North India.
3. A cross has been made between these species and the hybrid variety, combining the desirable qualities like thick stem, high sugar content, and higher yield is being grown in North India.

Cultivation of millets:

1. Several hybrid varieties of maize, Bajra, and Jowar have been developed in India.
2. These breeding programs have resulted in the development of high-yielding varieties that are resistant to water stress.

Question 11.
(i) Lifestyle diseases are increasing alarmingly in India. We are also dealing with large-scale malnutrition in the population. Suggest a process by which we can address both these problems.
Answer:
These problems can be addressed by the process termed biofortification,

(ii) Give any three examples to support your answer. (CBSE Sample Paper 2018-19)
Answer:
Biofortification can be done:
(a) by enhancing food quality with respect to protein, e.g. improved wheat, maize varieties, etc.
(b) by cultivating vitamin-enriched vegetables, e.g. vitamin A enriched carrots, spinach, pumpkin, etc
(c) by enriching micronutrient and mineral content in vegetables, e.g. iron and calcium-enriched spinach and bathua

Question 12.
What is biofortification? Mention the contribution of the Indian Agricultural Research Institute towards it with the help of any two examples. (CBSE Delhi 2018C)
Answer:
It is an improvement in the nutritional quality of food crops by breeding. Through this, levels of vitamins, minerals, proteins, and healthier fats are enriched in crops. Indian Agricultural Research Institute released several vitamin and mineral enriched vegetable crops like vitamin A enriched carrots and spinach; Vitamin C enriched bitter guard, mustard, tomato; iron and calcium-enriched spinach and bathua; protein-enriched broad lablab, French and garden peas.

Question 13.
(i) What is artificial insemination? Give its significance.
Answer:
Artificial insemination:

• It is the process in which the semen collected from a superior quality male is injected into the reproductive tract of the selected female by the breeder.
• The advantages of artificial insemination are as follows:
• Semen can be used immediately or stored/frozen and used at a later date when the female is in the right reproductive phase.
• Semen can be transported in the frozen form to a distant place where the selected female animals are present.
• Semen from one selected male animal can be used on a number of female animals.
• The disadvantage is that the success rate is fairly low.

(ii) Write a note on MOET. (CBSE Delhi 2008)
Answer:
Multiple Ovulation Embryo Transfer Technology (MOET):

1. It is a method to improve the herds and their size.
2. The steps in the method are as follows:
3. A cow is administered hormones (like FSH) to induce follicular maturation and superovulation, i.e. production of 6-8 ova in one cycle.
4. The cow is mated with the selected bull or artificially inseminated.
5. The fertilized eggs at 8-32 celled stages are recovered and transferred to surrogate mothers.
6. This technology has been used for cattle, rabbits, mares, etc.
7. High milk-yielding breeds of females and high-quality meat-yielding bulls have been bred successfully to increase the herd size in a short time.

Significance:

• Several cows (up to 3,000) can be inseminated by the semen of a single pedigree bull of good quality.
• Avoid the transportation of animals,
• The quality and quantity of progeny can be improved.
• New characters can be introduced in the progeny.
• It is economical.

Question 14.
What are the practices adopted to improve crop production?
Answer:
The practices adopted to improve crop production are as follows:

1. Addition of fertilizers to the soil.
2. Selective breeding.
3. Weed control.
4. Control of plant diseases.
   (a) Fertilisers: These are the chemical compounds that are added to the soil to increase fertility. They make up for the deficiency of the required nutrients and help in increasing crop production.
   (b) Selective breeding: Disease-resistant seeds are produced by selective breeding. Regular use of high yield variety results in better crop production.
   (c) Weed control: The unwanted plants or weeds are controlled by using certain chemicals called weedicides.
   (d) Control of plant diseases: Crops should be protected from insects, fungi, animals, and other diseases. It is very useful for increasing crop production. Insects are very harmful to crops. So insecticides should be used to kill insects.

Question 15.
Discuss the role of plant tissue culture in increasing food production. (CBSE Delhi 2011)
Answer:
Applications of tissue culture technique:

1. This technique is applied for the rapid multiplication of desirable and rare plants.
2. By this technique, an indefinite number of plants can be produced.
3. From the culturing of virus-free tissues of the shoot apex of an infected plant, it becomes possible to obtain virus-free plant in sufficient stock. The tissue culture technique has been used to obtain virus-free potatoes and sugarcane.
4. The technique (Embryo culture) is useful in overcoming seed dormancy, but also in producing viable plants from the crosses which normally fail due to the death of immature embryos.
5. The technique has been applied for obtaining a large number of haploid and homozygous diploids.
6. Somatic hybridization helps the fusion of cells belonging to different families.
7. This technique is also useful for the genetic improvement of useful plants.

Question 16.
“The benefits of a new variety can be achieved only if farmers grow the variety”. Explain.
Answer:
The seed of new variety must be multiplied and made available to the farmers. In-plant breeding, seed means any plant part that is used to grow a crop. Thus ‘seed’ would include grains of wheat, rice, etc. tubers of the potato, stems of sugarcane, etc., provided they are used for producing new plants.

Therefore, wheat grains used as food cannot be termed as seeds, whereas those used for raising a crop are called seeds. A seed of a variety with superior traits is called an improved seed, which must be of high purity and have a high germination percentage. It must also be free from weed seeds and from diseases.

Question 17.
(a) What is mutation breeding? Give an example of a crop and disease to which resistance was induced by this method.
Answer:
(a) Mutation breeding involves the following steps:

1. Inducing mutation(s) through various methods/ mutagens.
2. Screening the plant materials for disease resistance.
3. Multiplication of these selected plants for direct use or for use inbreeding.
4. Hybridization of the selected plant materials.
5. Selection for disease resistance, testing, and release as a variety.
6. Through mutation breeding, varieties of mung bean have been developed that are resistant to yellow mosaic virus and powdery mildew.

(b) Differentiate between pisciculture and aquaculture. (CBSE Sample Paper 2020)
Answer:

Aquaculture	Pisciculture
It involves the rearing all types of aquatic organisms to obtain products of economic value.	Pisciculture involves the rearing of fishes for obtaining food and fishery by-products such as fish oil, fish glue, fish manure, shagreen, leather, etc.

Question 18.
How can crop varieties be made disease resistant to overcome the food crisis in India? Explain. Name one disease-resistant variety in India of:
(i) Wheat to leaf and stripe rust
Answer:
Mutation breeding involves the following steps:
(a) Inducing mutation(s) through various methods/mutagens.
(b) Screening the plant materials for disease-resistance.
(c) Multiplication of these selected plants for direct use or for use inbreeding.
(d) Hybridisation of the selected plant materials.
(e) Selection for disease resistance, testing, and release as a variety.
(e) Through mutation breeding, varieties of mung bean have been developed that are resistant to yellow mosaic virus and powdery mildew.

(ii) Brassica to white rust (CBSE 2011)
Answer:
(a) Himgiri variety of wheat
(b) Pusa swarm of Brassica

Question 19.
(i) Name the technology that has helped the scientists to propagate on a large scale the desired crops in a short duration. List the steps carried out to propagate the crops by the said technique.
(ii) How are somatic hybrids obtained?
Or
Scientists tried to develop a single plant exhibiting the characteristic of tomato and potato by using cells from tomato and potato plants respectively. Name the procedure and list the steps to achieve this. (CBSE Delhi 2014, Outside Delhi 2019, Sample Paper 2020)
Answer:
1. Tissue culture:
(a) It is the technique of regeneration of whole plants from any part of a plant by growing it on a suitable culture/nutrient medium under aseptic/sterile conditions in vitro.
(b) The culture medium must supply the energy, inorganic nutrients, vitamins, amino acids, and growth regulators like cytokinins and auxins.
(c) By this method, called micropropagation, thousands of plants can be grown in a short period of time.

The advantages of micropropagation are:
(a) The plants produced are genetically identical and constitute some clones.
(b) A number of plants can be grown in a short period of time.
(c) Healthy, disease-free plants can be grown by meristem culture.
(d) Somatic hybrids can be raised by tissue culture, where sexual hybridization is not possible.

2. Somatic Hybridization: Fusion of isolated protoplasts from two different plant varieties each having desirable characters is called somatic hybridization. The resultant hybrid is called somatic hybrids. This somatic hybrid can be grown into a new plant carrying all desirable qualities.

Here we are providing Business Studies Class 11 Important Extra Questions and Answers Chapter 10 Internal Trade. Business Studies Class 11 Important Questions with Answers are the best resource for students which helps in class 11 board exams.

Class 11 Business Studies Chapter 10 Important Extra Questions Internal Trade

Internal Trade Important Extra Questions Short Answer Type

Question 1.
Differentiate between wholesalers and retailers.
Answer:
Difference between Wholesaler and Retailer:

Basis	Wholesaler	Retailer
1. Scale of Operations	Deals in large quantities and on a large scale.	Deals in small quantities and on a small scale.
2. Number of items	Handles a small number of items.	Handles a large number of items.
3. Trade Channel	First outlet in the chain of distribution	The second outlet in the chain of distribution
4. Customers	Sells to retailers and industrial users.	Sells directly to customers for final consumption.
5. Supplies	Receives goods from manufacturers/producers.	Receives goods from wholesalers and sometimes, from the manufacturers.
6. Location	The location of a wholesaler’s shop is not very important. A wholesaler may have a godown at any place.	Location of retailer’s shop near the residential areas is very important. It located in the heart of the city.
7. Window Display	The window display is not very important.	The window display is a must to attract customers.
8. Specialisation	Specializes in the products he deals in	Specialization is not possible as he deals in a large number of products produced by different producers.
9. Margin of Profit	Sells at a very low margin of profit as turnover is very fast.	Sells at a higher margin of profit as he has to spend on window dressing and pay higher rent for the shop at a central place.
10. After-Sale Service	Does not provide after-sale service.	Provides aftersale service.
11. Free Home Delivery	Does not provide free home delivery of goods to customers.	Provides free home delivery of goods to Customers.
12. Display	No window dressing and shop decoration are important.	Window-dressing and shop decoration are much more important to attract customers.

Question 2.
Mention the services provided by wholesalers to retailers.
Answer:
Services to Retailers:
Wholesalers render the following services to retailers –
1. Wide Variety: A retailer has to stock a large variety of products to meet the individual tastes and needs of its customers. Since he can easily purchase the required goods of different varieties from a wholesaler, he is relieved of the botheration of collecting goods from several manufacturers.

2. Regular Supplies: A wholesaler is always well stocked with different types of goods. Therefore, the retailers are assured of a quick and regular supply of their requirements from time to time. They need not maintain a large stock of goods and have no fear of running out of stock. The wholesaler serves as their warehouse keeper from whom they can quickly replenish their stocks. The wholesaler saves the retailers from the trouble of searching out and assembling goods from several manufacturers.

3. Specialisation: The wholesalers generally specialize in one line of goods. They buy good quality goods at the minimum possible price from the manufacturers. Retailers receive the benefit of such specialization when they buy goods from wholesalers. Wholesalers advise retailers on matters like quality, price, and timing of purchase. They inform the retailers about the new products, their uses, quality, prices, etc. They may also advise on the decor of the retail outlet, allocation of shelf space, and demonstration of certain products.

4. Publicity: Wholesalers advertise their goods regularly. Such publicity helps retailers in increasing their sales. Some wholesalers also guide retailers’ in-store layout and selling techniques. The retailers are benefited as it helps them in increasing the demand for various new products.

5. Credit: Wholesalers grant liberal credit facilities to retailers. As a result, retailers can carry on a large volume of business even with a small amount of working capital. They would be placed in a difficult position if they were to buy goods on cash payment.

Question 3.
List the various types of retail trade organizations.
Answer:
Types of retail trade organization:
Retail traders may broadly be classified into two categories –

Question 4.
Explain the automatic vending machine as a source of retail trade.
Answer:
Automatic Vending Machines:
A vending machine is a new and complementary form of retailing. It is a slot machine operated by coins or tokens. The buyer inserts the coin or a token into the machine and receives a specified quantity of a product from the machine. Vending machines are used to sell prepacked and low-cost products of mass consumption, soft drinks, hot beverages, cigarettes, tickets, etc. In Delhi, Mother Dairy sells milk through vending machines.

The vending machines have become popular due to convenience in the handling of products and in the collection of payment. The customer gets a fresh supply of goods with uniform weight and quality. Moreover, vending machines can sell goods at places and at times when other types of retailing are not convenient or economical. There is a saving of labor costs. But initial investment in the machine is quite high. The machine requires regular repairs and maintenance.

The merits of vending machines are as under –

1. It is convenient for the customers to buy the goods from the machine.
2. Machines provide quick service.
3. Machine develop the habit of self-service among the customers.
4. Special peeks are to be developed by manufacturers that suit the machine.
5. Care has to be taken about replenishing the stock of the machine regularly.
6. Machines are useful in selling only consumer goods that are usually edible in nature i.e. candies, chocolate, soft drinks, coffee, etc.

Question 5.
Write an essay on the organization of wholesale trade.
Answer:
Organization of Whole Trade Board of Directors

Wholesale trade is generally carried on a large scale and a large amount of capital investment is required for it. Therefore, a wholesale firm is generally organized in the form of a joint-stock company or a partnership. The company works under the overall supervision of the board of directors and the managing director. The organization is divided into sections. Every section is managed by a sectional head. All sectional heads are responsible to the managing director. Each section is divided into various departments. The head of each department is accountable to the sectional head concerned.

The organization of wholesale trade may be divided into the following sections –
1. Administrative Section:
This section looks after the overall planning and control of the wholesale trade. It is usually divided into several departments.
(a) Records and filing department: This department handles the firm’s records and files. Filing relates to having records of the business correspondence for future reference. Proper binding is also necessary for an easy and quick location of files, whenever required.

(b) Correspondence department: This department is responsible for the receipt, typing, and despatch of all letters. Timely and prompt reply of all incoming letters is essential for the success of a business. A copy of every letter sent by the firm is sent to the filing department for ready reference.

(c) Accounts and finance department: This department is concerned with the proper maintenance of the firm’s accounts. These accounts are related to the firm’s purchases, sales, receipts, payments, debtors, creditors, etc. This department is also responsible for preparing budgets and raising the necessary funds for a business. This department works under the supervision and control of the chief accountant and clerks working under him.

(d) Labour department: This department is responsible for the recruitment, selection, training, remuneration, promotion, etc. of employees.

2. Cash Section:
This section is concerned with the receipt and payment of cash. It is the responsibility of this section to ensure that all payments are made promptly and on the due dates so that the firm enjoys a good credit standing in the market. Similarly, this department takes steps for prompt collection of debts from the firm’s debtors in order to minimize bad debt losses. For handling small payments, there is a petty cashier who is provided a small amount of impress cash. When he has spent the entire amount, the head cashier advances him some more important cash.

In some wholesale firms, there is a separate credit and collection department which keeps a check on the credit sales.

3. Planning and Executive Section: This section consists of the various functional departments.
(a) Buying department: This department is concerned with buying goods in bulk from different producers. Before buying goods it invites Quotations from the producers. After comparing different quotations with regard to price, quality of goods, delivery period, etc. it places its orders.

When the goods are received, they are compared with the order. If there is any discrepancy or damage to goods, the matter is duly settled with the supplier. After receiving the goods, arrangements are made for their storage. The buying department is headed by an expert buyer who has complete knowledge of the various producers and the market conditions.

(b) Sales department: This department is responsible for selling the goods to retailers. It conducts market surveys to find out the tastes, fashions, etc. of the customers and other market conditions. This information is passed on to the buying department. The sales department also handles the complaints of retailers. The sales manager is the head of this department. Several salespersons work under him. Their recruitment, training, remuneration, etc. is also the responsibility of the sales manager.

(c) Publicity department: This department is concerned with advertising goods in order to create demand. It also arranges fairs and exhibitions of products.

(d) Despatch department: The function of this department is to despatch goods to various retailers according to the instructions it has been given. It handles packing, marking, and labeling of goods and arranges for the delivery of goods to the retailers. Many wholesale firms have a separate warehousing department also.

Question 6.
What are multiple shops or chain stores? Explain its features, merits, and limitations.
Answer:
Chain-Stores (Meaning): Chain stores or multiple shops are a group of branch shops dealing in the same line of goods under single ownership and centralized management. A chain store is a chain of identical retail stores situated in different localities. Such a chain may be established by a manufacturer or by a merchant. It is known as chain stores in the United States and multiple shops in Europe. Bata Stores and DCM Stores are examples of chain stores in India. These normally deal in standardized and branded consumer products that have rapid sales turnover.

Distinctive Features:

1. Large Size: Chain stores are an example of large-scale retail establishments. These are located popularly in the area where a sufficient number of customers can be approached.
2. Company Form: These stores are organized as a joint-stock company. All stores are owned and controlled by the same company. There are centralized management and control.
3. Specialization: All stores in a chain deal in the same line of products, usually necessities.
4. Centralized Purchasing: Goods for all chain stores are purchased by the head office. Through centralized purchasing. These shops enjoy economies of scale.
5. Decentralized Selling: Chain stores are situated in different parts of the city and country. These shops are run by the same organization and have identical merchandising strategies.
6. Elimination of Middlemen: A chain store is a form of direct selling in which middlemen are eliminated.
7. Uniform Price: Goods are sold in all the stores at a fixed price.
8. Standardization: Decoration of stores and window displays follow a uniform style or pattern.
9. Cash Sales: Goods are sold on a cash and carry basis. There is no loss on account of bad debts.

Merits:
1. Economics of Scale: Goods for all chain stores are purchased by the head office. Such bulk buying results hr several economies like heavy discounts, saving in transport costs, etc. Benefits of specialization and centralized management are also available. Large capital permits expansion and growth.

2. Convenient Location: Chain stores are located to suit the conveniencFoftheeustometa. This helps in increasing sales turnover and in retaining contact with customers. These shops me located in fairly populous localities where a sufficient number of customers can be approached.

3. Low Operating Costs: Chain stores sell goods on a cash basis H so that there is no loss due to bad debts. There is an economy in advertising because one advertisement is enough for all the stores. Large and rapid turnover and common advertising are possible.

4. Low Price: Due to low operating costs and the elimination of middlemen, goods are sold at relatively cheaper rates. A manufacturer can establish direct contact with customers through chain stores.

5. Flexibility: If one store out of stock, supplies can be easily transferred from a nearby store belonging to the same chain. Such inter-branch transfers help to avoid loss due to shortage or surplus of stock. If a branch is not doing well it can easily be closed down and a new one can be opened in another place without really affecting the profitability of the organization as a whole.

6. Public Confidence: Fixed prices arid standard quality help to increase confidence among consumers. Customers can easily identify the chain stores on account of uniform decoration and design.

7. Diffusion of Risk: Lack of demand in one area 4oes affect the
sales in other stores. But the loss incurred by one store can easily be absorbed by profits made in other stores reducing the risk of an organization.

8. Simplicity of Control: Goods are sent to the different stores by the head, office and cash receipts are sent by each branch to the head office. Price and the other policies are uniformly laid down for all the stores. In this way, the office can exercise effective supervision and control over all the branches.

Limitations:
1. Limited Choice f Ghain deal in a limited range of products and do not offer a wide variety of choice to customers,

2. Lack of Personal Touch: The paid employees of chain stores do not take a personal interest in each and every customer Tltey adopt a ‘take it or leave it’ attitude towards the customers. The owner loses all personal contracts with the customer Lack of initiative in the employees some times leads to indifference and lack of personal touch in them

3. Lack of initiative: The employees of chain stores have no freedom to make decisions. Rigid control and uniform policies discourage initiative on their part. They cannot exhibit business opportunities or adapt to local needs. This makes them habitual of looking up to the head office for guidance on all matters and takes away creative skills of their own.

4. Heavy Overheads: The head office has to incur heavy expenditure on rent, wages, salaries, furniture, fixtures, etc.

5. No Facilities: Customers do not get credit, home delivery, or other facilities. Therefore, chain stores do not attract rich customers. This discourages certain types of people to visit multiple shops.

6. Local Competition: Chain stores are considered a threat to small independent retail stores. Therefore, local retailers are hostile towards these stores and offer tough competition.

7. Remote Control: The head office is usually far removed from the stores. Therefore, there is a lack of close contact between them.

Question 7.
Super Market is the most famous retail trade-in city. Mention its merits and demerits.
Answer:
Super Market (Self-Service Store):
Meaning:
A supermarket of Bazar is a large retailing business unit selling a wide variety of consumer goods such as food and grocery items on the basis of the low-margin appeal, wide variety, and assortments, self-service, and heavy emphasis on merchandising appeal.

A supermarket deals mostly in food and grocery items and convenience goods like household goods, hosiery items, cosmetics, medicines and drugs, electronic appliances, etc. It is generally situated at the main shopping center. Goods are kept in open racks, and the price and quality are clearly labeled on the goods.

A consumer can make a selection of goods moving from counter to counter and pick up the selected goods and place them in a trolly. After he has completed his selection, the trolly will be carried to the exit where a person computes the total charge and the buyer makes payment to the cashier and then takes delivery of goods. Thus, supermarket follows the policy of self-help’ by the customers. The customers are not pressurized by the salesmen. That is why many people are attracted to the supermarket.

The supermarket is organized on a departmental basis and a customer can buy various types of goods under one roof. A supermarket can be differentiated from the departmental store on the main ground that there are no salesmen at the super Bazar to deal with the customers. The customers are free to choose the commodities of their choice. Moreover, a supermarket does not offer certain services which are usually provided by a departmental store. For instance, a supermarket does not allow credit sales and does not provide free home delivery service.

Features:
The main features that distinguish a supermarket from other retail institutions are discussed below –

1. A supermarket generally carries a complete line of food items and groceries in addition to non-food convenience goods including drugs, cosmetics, household goods, etc.
2. Its organization resembles a departmental store. A customer can buy his requirements under one roof.
3. A supermarket operates on the principle of self-service. There are no salesmen or shop assistants to help or pressurise the customers in a supermarket. That is why it is known as a self-service store. The distribution cost is, therefore, lower.
4. A supermarket is a low-cost retail institution in comparison with Other types of retail stores. The prices of the products are generally lower than other types because of bulk purchasing, lower operational cost, and low-profit margins.

Merits:
The following are the merits of a supermarket –
1. A supermarket is a large-scale retailing store. It enjoys all the benefits of large-scale buying and selling. Because of this reason and because of large turnover, its operating costs are lower and it can sell goods at cheaper rates. These outlets are not only convenient but also economical to buyers for making their purchases.

2. Considerable attention is paid to the package of the products since there are no salesmen to convince and pressurize the customers. Many people like this distinct feature of self-service. They enjoy the freedom to ccunpar£-iii£fereat4minda of Q.product- and making a selection of goods without pressure from anybody.

3. The customers can make all their purchases under one roof. A supermarket provides goods to customers at cheaper rates because of large turnover and absence of salesforce. The administrative and distribution overheads per unit of a product are also lower.

4. Since supermarket sells only on a cash basis, there is no chance of bad debts.

Demerits:
A supermarket suffers from the following drawbacks –
1. There are certain people who give greater weightage to personal attention. Such people do not like shopping through the supermarket as there are no salesmen.

2. Supermarkets cannot handle commodities that require personal explanation by the salesmen. It works on the self-service principle.

3. Some customers handle the goods carelessly and misuse the ‘ opportunity of self-service and selection. This may cause loss to the supermarket.

4. In practice, supermarkets have not been able to create low price appeal among the customers because of higher overhead expenses.

5. Establishment and, running off a supermarket requires huge; investment, and its turnover should be higher to keep the overhead expenses under reasonable limits. Thus, a supermarket cannot be established if the necessary capital is not available and a Jarge turnover is not expected. In other words, supermarkets are not suitable for smaller towns.

Question 8.
Write in brief about Telemarketing or Teleshops in the modern world.
Answer:
Telemarketing (Teleshops): Telemarketing means a form of non-store retailing in which the seller initiates contact with a shopper ‘ and closes the sale over the phone. A telemarketer may procure the names and telephone numbers of his prospective customers from the telephone directory and other sources.

Popular products such as electrical appliances, health products, and educational aids and services such as magazine subscriptions, credit-card membership, etc. can be promoted through telemarketing. ICICI and Citibank follow this technique to popularise their credit cards among people.

A telemarketer can advertise the product, its features, uses, and price through a TV network, say Doordarshan, Metro, Zee TV, or Sony TV channel. The interested customer can place an order directly over telephone, fax, e-mail, or by post to the advertiser, say, Asian Sky Shop. The delivery may be effected through courier, or post office, or the manufacturer’s distribution van. Payment is to be made at the time of delivery. Telemarketing is a very convenient method of shopping. It is becoming popular in India.

From the point of view of the customer, buying or ‘dial-n-order’ is a very convenient method of shopping. One need not visit the store for shopping. One can place an order over the phone and make payment through a credit card. Teleshopping and getting free home delivery at residence is not only convenient but also cheaper as no middlemen are involved. The popularity of telemarketing would be attributed to the growing focus on customers.

From the point of view of the seller, telemarketing is a cheaper method of retailing. It saves expenditure on retail showrooms and salesforce. Even a firm with retail outlets or stores in major cities can reach customers at far off places through telemarketing. The growing satellite networks have created brand awareness and facilitated Telebuying and selling. The industry grew rapidly over 5 years to reach a size of2000crores with over one million consultants.

Telemarketing is a major tool of direct marketing in the USA and is gradually gaining acceptance in India. But telemarketing has the disadvantage of lack of personal touch with the buyers. Moreover, the buyer can’t inspect the goods personally before placing an order. Some people don’t like teleshopping. They get irritated when they receive unsolicited calls from the call centers, say, for the marketing of credit cards or personal loans.

Question 9.
What are Internet or Online marketing, its benefits, and the difference between traditional marketing and online marketing?
Answer:
Internet Marketing:
Internet marketing is emerging as an important form of e-commerce, In this form of marketing, orders are received and processed on the internet. The internet is the world’s largest computer network. In fact, it is a ‘network of networks’ of computers throughout the world. A computer network is basically a bunch of computers hooked together for receiving and transferring information.

The facility of linking millions of computers is provided through the internet. The use of the internet by marketers or producers for the purpose of selling their products is known as internet marketing. Internet marketing can take several forms e.g. Online services, worldwide webs (www), and CD ROMs.

Internet:
The internet is a global web or computer network that makes instantaneous global communication possible. Internet usage has surged with the development of the user-friendly World Wide Web (www) and Web browser software such as Microsoft Internet Explorer or Netscape Navigator. Users can surf the internet and send e-mails, shop for products, and can get news and other information.

The internet itself is free though the user has to pay some fee to the Internet Service Provider to be hooked up to it. Thus, the internet is changing the way marketing is done. Internet technology provides marketers with faster ‘ more efficient and much more powerful methods of designing, promoting, and distributing products, conducting research, and gathering market information.

Online Marketing:
The users of the internet are younger, educated, and more affluent. Business firms can use the internet to reach such users by sending catalogs, price lists, etc. through e-mail. Besides advertisement, the sellers can attend to the queries of the buyers and clinch the deal on-line. The buyers can on their own also log on the t computer to know about the products of different manufacturers and decide to buy the products that suit them.

The use of electronic channels for the direct marketing is on the rise these days. The term e-commerce describes a wide variety of electronic platforms such as the sending of purchase orders to suppliers via electronic data interchange (EDI), the use of fax and e-mail to conduct transactions, the use of ATMs (automated teller machines) and smart cards to facilitate payments and obtain digital cash and the use of internet an online > services.

Thousands of business firms have established their presence on the internet. A new firm, big or small, can do so in two ways:
(a) It can buy space on a commercial on-line service; or (b) It can open its own website. In the case of online service, the firm has to pay an annual fee and also a small commission as a percentage of sales.

But these days, companies prefer to set up their own websites. Such a website offers information * about the company’s history, products, and services. The company can interact with anyone visiting the website and explore the possibility of concluding sales.

Benefits of Online Marketing:
The marketers can enjoy the following benefits of internet marketing –

1. The cost of digital catalogs is much less than the cost of printing and mailing paper catalogs;
2. Digital catalogs can be revised quickly and without much difficulty.
3. The marketers achieve economy in operations. They have to maintain low inventories and incur low costs on storage and insurance.
4. Internet marketing helps in relationship building with the customers. Online marketers can interact with customers and learn from them and improve their products.
5. Marketers can contact the people who have visited their website and make them attractive offers to affect sales.
6. Orders can be received quickly.
7. The marketers can approach customers living anywhere in the world. Thus, there is no distance gap between the sellers and the buyers.
8. Marketers can size up the audience, know how many people visited their online site. This information helps in improving sales offers and advertisements.
9. Online marketers can build relationships with customers by interacting with them.

Comparison of Online and Traditional System of Marketing

	Online Shopping	Traditional Shopping
Advantages	Convenience Saves time Reduces impulse buying	Five senses influence buying Memory trigger Product sampling Exposure to new items Social interaction
Disadvantages	Less price and selection control Forget items Reliance on computer Delivery fee	Time-consuming Waiting for lines and parking Carrying groceries home Impulse buying Safety

Question 10.
A franchise is a buzzard in the modern marketing world. What are its merits and limitations?
Answer:
Franchise: Franchise is a commercial concession by which a company or person grants a retailer the right of selling its products or services in a specified area. The owner of a product (known as a franchiser) permits another business firm (called franchisee) to sell the product in exchange for royalty payments.

The franchise is the right or privilege to use an established business system is “a continuing relationship in which franchisee provides licensed privilege to do business plus assistance in organizing, training, merchandising and management in return for a consideration from the franchise.” A franchising operation is a contractual relationship between a franchiser and franchisee.

Thus, the franchise is a system under which the owner of a product or service grants the franchisee the exclusive right to distribute the product or service in a specific geographical area on specified terms and conditions. The owner of the product or service who grants the right to distribute is known as the franchiser. The person or firm who acquires the right or franchise is called the franchisee.

A franchise system is one in which a manufacturer grants selected retailers the exclusive right to sell their products or services in specified areas. Such retailers are required to promote and sell the product in a specific manner. There is a written agreement between the franchiser (supplier) and the independent franchisee (retailers) on the terms and conditions of the franchisee.

The franchise is found in several types of businesses. Consumer items such as cosmetics, readymade garments, television sets, V.C.R., music system, computers, machinery and equipment, automobiles, servicing of consumer durables, computer training, real estate are some of the examples where the franchise is popular. Wimpy, Nirulas, Essex farms, Snowhite Drycleaners, etc. are notable examples of franchises in India.

The franchiser receives either a fixed sum or periodical royalties for allowing the use of trademark and providing training. The franchisee pays for a reliable and proven business. He gets professional advice and national sales promotion support from the franchiser. Generally, all franchised outlets of a product or service have an identical trademark, standard symbols, standardized products, and uniform business policies. The franchisee has to raise his own finances.

Franchise arrangements may be of the following types –
1. Product and Trade Name Franchise: In this arrangement, the franchisee acquires the right to use the product and trade name of the franchiser. The franchisee can also use window-display, standardized operating procedures,s and a prescribed territory to the franchisee.

2. Exclusive Dealership: Under this system, a manufacturer signs an exclusive agency contract, with a distributor. The distributor gets the exclusive right to sell the product within a specified geographical area. The distributor agrees to certain conditions of the manufacturer, e.g. adequate stock, prices to be charged, the services to be provided, etc. The exclusive dealership is popular in automobiles.

3. Conversion Franchising: Herein an established businessman gets affiliated with a franchiser. The two share the benefits of a franchising relationship.

4. Combination Franchising: In this arrangement, two franchises share a location and management, site selection, training of the staff, financing, and marketing, record keeping, and production business also arranged.

5. This is a fully integrated and continuous relationship between a franchiser and franchisee. The relationship covers total operations of the franchise including product or service, trademark quality control, strategy, etc. Fast food restaurants such as McDonald’s are an example of such a franchise.

Merits:
The main advantages of the franchise are as follows –
1. Availability of Established Brands: The franchisee acquires the right to use the popular brand name or trademark of the franchiser. Association with an established name provides a ready market. A franchise gives a quick and easy start in business. There are greater chances of success of the franchisee because the products are well known.

2. Standardised Goods and Services: The reputation of the franchiser depends largely on the quality of products and services supplied by the franchisee. The franchiser takes steps to ensure that products and services in all the franchised outlets are uniforms. He provides the raw materials and keeps close control of the quality of goods. The quality of products helps the franchisee to satisfy his customers by offering quality products.

3. Advertising Support: The franchiser carries on advertising. The franchisee gets the benefit of such advertising and the reputation or goodwill of the franchiser. The products are well advertised in various media and are known to the people. It is easier for the franchisee to promote the sale of products.

4. Financial Assistance: Franchiser offers a wide range of financial assistance to the franchisee in the form of short-term credit, lower down payment, flexible repayment terms, etc. Financial assistance is available for plant and equipment, accounts receivable, etc.

5. Managerial Training: Franchisers provide technical and managerial training to franchisees and their staff. Prior to opening a franchise, counseling and training are provided in the professional and profitable operation of the business and in the fields of inventory management, accounting, sales promotion, advertising, etc. Assistance is also available in site selection, marketing research, in addition to ongoing business assistance.

6. Established Business Methods: The franchisee can capitalize on the accumulated knowledge, experience, and skill of the franchiser. He does not have to build a business from scratch. The franchisee buys a business that has proved its success and can, therefore, avoid many of the pitfalls faced by small business owners. The franchiser makes huge investments in the innovation of products and research and development.

7. Economies of Scale: Due to the group or cooperative purchasing,
costs of products are reduced. Mass buying provides economies of scale. The distribution system between franchisor and franchisee in the shortest possible time. Marketing costs are lowered.

8. Uniform Control System: All franchising outlets are subject to the uniform control system. Standardized inventory control enables the franchiser to have more accurate information about the merchandise available and needed. Standardized reporting procedures are also helpful. It enables the franchiser to increases his goodwill and reputation.

9. Higher Success Rate: On average, franchises survive better than other business start-ups. The success rate, of franchises, is higher than that of independently owned businesses, Therefore, franchises are more attractive to middle-aged people who are less willing to take full risk of starting their own business. Potential income can be higher than independent small businesses.

10. Benefits to Franchiser: Franchise enables the franchiser to enter a new business territory at a low cost. It is a relatively quick way to raise cash and expand business operations. Owner-operators (franchises) are highly motivated. Franchises can be used as outlets for goods and services manufactured or supplied by the franchiser. This provides economies of scale in manufacturing and purchases. The franchiser can exercise control over products, services, and processes. The franchiser gets feedback about the product’s popularity from the franchisee.

Limitations:
The franchise system suffers from the following disadvantages –
1. Fees and Royalties: Costs of a franchise include license fees and fees for the initial processing of the application. It is payable when the franchise agreement is signed and is not refundable. Other costs include down payment on equipment, decoration of the outlet, office furniture, publicity on opening, etc. The franchise has to bear travel and living expenses while undergoing training. In addition, He has to pay a royalty on a continuing basis.

2. Lack of Freedom: The franchisee does not have the freedom to run a business like an independent owner. He has to conform to the controls exercised by the franchiser to ensure quality and uniformity of standards of product or service. Quality standards and specifications for all items used in the franchise are established. The freedom of purchasing is also restricted.

3. Limited Product Line: The franchiser controls the products or services sold at the franchisee’s outlet. The franchisee cannot introduce other products except those permitted by the franchiser.

4. Restriction on Sale of Franchise: Sale, transfer, or assignment of ownership interest requires the franchiser’s approval. Even when the sale is approved, the new franchisee is required to conform to the terms and conditions of the franchise.

5. Disadvantages to the Franchiser: The franchiser cannot treat or control the franchisees like his employees. Franchisees tend to become quite vocal and demanding if they feel they are not getting fair treatment or do not see benefits in the franchise network. Extensive communications are necessary and the costs of visiting the franchisees at distant places can be high. The franchiser has to bear the expenses of administration, training, advertising, legal services, supervision, etc.

Question 11.
Wholesalers are parasites for society and should be eliminated as soon as possible. Give arguments in favor and against of elimination of wholesalers.
Answer:
Elimination of Wholesalers: Wholesalers perform several useful functions and render many vital services. They provide a ready sales outlet to manufacturers and serve as a source of a steady supply of goods for retailers. Therefore, they provide a valuable link between producers and retailers. But in recent years there has been a trend towards the elimination of wholesalers.

Growth of large-scale retailing institutions, development of quick means of transport and communication, growth of cooperative movement among consumers, the rise of specialized advertising agencies, etc. have made it possible, in certain cases, to establish a direct link between producers and retailers.

Arguments in Favour of Elimination: Some people insist that wholesalers exploit producers and retailers. Therefore, they should be eliminated and their functions should be taken over by producers and retailers.

The following arguments are given in favor of the elimination of wholesalers –
1. Reduction in Prices: Wholesalers charge a substantial margin of profit and add to the cost of distribution. This results in higher prices payable by the ultimate consumers. Prices payable by consumers can be reduced by eliminating the wholesalers.

This would increase the sales volume which would benefit the producers. Many producers want to reduce prices to maximize sales in conditions of cut-throat competition but wholesalers discourage reduction in prices. Wholesalers are the parasites of society. The customers have to bear the cost of wholesalers.

2. Faster Distribution: Wholesalers are mere transfer agents who set up unnecessary road-blocks in the process of distribution. Their, interference in the distribution channel obstructs the smooth and quick flow of goods from manufacturers to consumers. By eliminating the wholesaler’s goods can be supplied to consumers more quickly. Modem means of transportation and communication do not favor unnecessary middlemen in the channels of distribution.

3. Manipulations: Many wholesalers indulge in malpractices such as hoarding and adulteration. They push up prices by creating an artificial scarcity of goods. Such malpractices can be avoided by eliminating the wholesalers. Wholesalers do not render services correspondingly for the profits they earn while handling goods.

4. No Risk-bearing: Wholesalers assume the little risk and make no improvement in the distribution techniques. Therefore, there is little justification for the existence of wholesalers. Sometimes, even the existence of wholesalers hinders the smooth flow of goods and services.

5. Unreliable: A manufacturer faces a sudden decline in sales when wholesalers discontinue their line of goods and switch over to a different competitive line. Many wholesalers sell so many products that they are unable to give equal attention to pushing the sale of all the products.

6. Better Alternatives: Large-scale retailers such as departmental stores, chain stores, and supermarkets have adequate funds and space to buy goods in bulk directly from manufacturers. They can bear risks and promote sales on a large scale. Therefore, they do not need the services of wholesalers.

Arguments against Elimination:
Those who believe that wholesale trade is essential, give the following arguments –
1. Undivided Attention: If wholesalers are eliminated, the producer will also have to undertake the distribution of his goods in small lots to a large number of widely scattered retailers. As a result, he will not be able to concentrate fully on production. The economies of large-scale production will have to be sacrificed. Wholesalers perform many marketing functions like buying and assembling, selling, market research, advertisement, transport, etc.

2. Necessary for Small Producers: Small manufacturers are not in a position to distribute their goods. Due to a large number of small producers and retailers, wholesalers still dominate the field of distribution of goods. Wholesalers bear the risk of fluctuations in prices, purchase of raw material, etc. Above all, they will have to find out means of financing which small producers are unable to do.

3. Storage of Goods: If wholesalers are eliminated, retailers will have to maintain large stocks and bear the risk of price fluctuations. Which they are generally unable to bear due to limited capital and lack of enough space.

4. Savings in Costs: Wholesalers are experts in the task of distribution. Therefore, they save expenses through more efficient marketing of goods. They maintain a sales force that calls upon retailers regularly. Their expenses are lower than those of manufacturers’ who sell directly to retailers. By eliminating the wholesaler, costs of distribution may increase. The manufacturers are often solely dependent upon distribution by the wholesalers as they can’t handle distribution themselves.

5. Seasonal Products: Some products are produced throughout the year but their demand arises only during a particular season. If wholesalers are eliminated, producers will have to keep huge stocks of such products. They will require a large amount of capital during the off-season.

6. Financing: In case wholesalers are eliminated, the manufacturers and retailers will have to invest more capital in the business.

Conclusion: By eliminating the wholesaler, his functions cannot be eliminated. These functions will have to be performed by either producers or retailers. Therefore, the elimination of the wholesaler is desirable only in those cases where manufacturers or retailers can perform these functions more efficiently than the wholesaler. Only large and well-established producers or retailers may be in a position to do so. Therefore, a wholesaler is an essential link in the distribution of all such commodities wherein producers and retailers are small and unable to assume the burden of wholesale trade.

In brief, wholesalers neither can be nor should be eliminated because of their services to the manufacturers, retailers, consumers, and society as a whole.

Here we are providing Class 12 Biology Important Extra Questions and Answers Chapter 8 Human Health and Disease. Important Questions for Class 12 Biology are the best resource for students which helps in Class 12 board exams.

Class 12 Biology Chapter 8 Important Extra Questions Human Health and Disease

Human Health and Disease Important Extra Questions Very Short Answer Type

Question 1.
What is health?
Answer:
It is a state of complete physical, mental and social well-being of a person.

Question 2.
What is a disease?
Answer:
Malfunctioning of one or more organs characterised by signs and symptoms is called disease.

Question 3.
Write the role of interferons. (CBSE Delhi 2019(C))
Answer:
Role of interferon. These are glycoprotein released by virus-infected cells. They protect the adjoining cells from the attack of the virus.

Question 4.
Define autoimmunity.
Answer:
It is an abnormality which sometimes occurs in the immune system and instead of destroying foreign molecules, it attacks the body’s own cells.

Question 5.
A boy of ten years had chickenpox. He is not expected to have the same disease for the rest of his life. Mention how it is possible. (CBSE 2009)
Answer:
The body will acquire active immunity as the antibodies formed will protect him from the attack of microbes of chickenpox.

Question 6.
What is it that prevents a child to suffer from a disease he/she is vaccinated against? Give one reason. (CBSE 2010)
Answer:

1. Antibodies
2. These antibodies neutralise the action of antigens.

Question 7.
Name the pathogen which causes Typhoid. Name the test that confirms the disease. (CBSE Delhi 2019 (C))
Answer:
Causative pathogen: Salmonella typhi Test: Widal test

Question 8.
Name two types of cells in which the HIV multiplies after gaining entry into the human body. (CBSE 2008)
Answer:

1. T-Lymphocytes
2. White Blood Corpuscles (Macrophages).

Question 9.
Why is a secondary immune response more intense than the primary immune response in human? (CBSE 2014)
Answer:
It is because the human body appears to have more memory of the first encounter.

Question 10.
When does a human body elicit an anamnestic response? (CBSE (Outside Delhi) 2013)
Answer:
The primary immune response is of low intensity; a subsequent encounter with the same pathogen elicits a highly intensified anamnestic or secondary response.

Question 11.
Name the two intermediate hosts which the human liver fluke depends on to complete its life cycle so as to facilitate parasitisation of its primary host. (CBSE Delhi 2014)
Answer:

1. Freshwater Snail
2. Fish

Question 12.
Indiscriminate use of X-rays for diagnoses should be avoided. Give reason. (CBSE (Delhi) 2015)
Answer:
X-rays cause mutation thus may lead to cancer.

Question 13.
Give the scientific name of the source organism from which the first antibiotic was produced. (CBSE Sample paper 2018-19)
Answer:
Penicillium Notatum

Question 14.
Name two diseases whose spread can be controlled by the eradication of Aedes mosquitoes. (CBSE 2018)
Answer:
Dengue and chikungunya

Question 15.
How do cytokine barriers provide innate immunity in humans? (CBSE 2018)
Answer:
Cytokine barriers: Cytokines inhibit viral replication. Virus-infected cells secrete proteins called interferons which protect non-infected cells from virus.

Question 16.
Name two recent incidences of wide-spread diseases caused by Aedes mosquitoes. (CBSE Delhi 2008)
Answer:

1. Dengue
2. Chikungunya

Question 17.
How does the human body respond when haemozoin produced by Plasmodium is released in its blood? (CBSE Delhi 2019 (C))
Answer:
As haemozoin is released in the blood, the patient shows symptoms of malaria such as restlessness, sleeplessness, muscular pain and chilliness. In response to chill, the body temperature rises.

Question 18.
How does saliva act in body defence? (CBSE Delhi 2004)
Answer:
Human saliva contains lysozyme, a lytic enzyme, which kills the germs in the food.

Question 19.
Name the type of cells that produce antibodies. (CBSE 2004)
Answer:
Lymphocytes which is a form of leucocytes (white blood cells) produce antibodies.

Question 20.
Why sharing injection needles between two individuals is not recommended? (CBSE Delhi 2013)
Answer:
Sharing of injection needles between two individuals may cause the transmission of AIDS and Hepatitis B.

Question 21.
How do monocytes act as a cellular barrier in humans to provide innate immunity? (CBSE Delhi 2018C)
Answer:
Monocytes kill bacteria by the process of phagocytosis.

Human Health and Disease Important Extra Questions Short Answer Type

Question 1.
Make a list of common infectious diseases.
Answer:
Common infectious diseases: Depending on the pathogen, infectious diseases are as follows:

Question 2.
Given below are pairs of pathogens and diseases caused by them. Which of these is not a matching pair and why?
(i) Virus Common Cold
(ii) Salmonella Typhoid
(iii) Microsporum Filariasis
(iv) Plasmodium Malaria
Answer:

1. (iii) is not matching.
2. Microsporum is a fungus which causes ringworm disease. Filariasis is caused by Wuchereria bancrofti and W. Malayi (roundworm).

Question 3.
Differentiate between antibodies and interferons.
Answer:
Differences between antibodies and interferons:

Antibodies	Interferons
1. They are slow-acting and long-lasting.	1. They are quick acting and temporary.
2. They act outside the cells.	2. They act inside the cells.
3. They act against bacterial and viral infections.	3. They act against the virus only.

Question 4.
(i) Name the source plants of heroin drug. How is it obtained from the plants?
Answer:
Papaver somniferum is the source plant of heroin drug. It is obtained by acetylation of morphine, which is extracted from the latex of poppy plant (Papaver somniferum).

(ii) Write the effects of heroin on the human body. (CBSE 2018)
Answer:
Heroin is depressant and slows down body functions.

Question 5.
Mention one application for each of the following:
(i) Passive immunisation
Answer:
(i) Passive Immunisation: When ready¬made antibodies are introduced into the body, it is called passive immunisation. Passive immunisation provides a quick immune response in the body.

(ii) Antihistamine
Answer:
Anti-Histamines: Anti-Histamines are the chemicals which are given against allergic reactions.

(iii) Colostrum (CBSE 2017, 2019)
Answer:
Colostrum: Colostrum is the yellow fluid produced during the initial days of lactation. It is rich in antibodies and is essential to develop resistance in a newborn baby.

Question 6.
What is a vaccine? (CBSE Delhi 2019 C)
Answer:
Vaccine: It is a preparation of dead or altered (weakened) germs of a disease which on entry into the body of a healthy person provide temporary or permanent active/passive immunity by inducing antibody formation. Thus antibody provoking agents are called vaccines. The vaccine provides artificial active immunity.

Question 7.
Name the primary and secondary lymphoid organs. (CBSE Delhi 2019 C)
Or
State the function of primary and secondary lymphoid organs. (CBSE Delhi 2011)
Answer:
Primary lymphoid organs:

• Bone Marrow
• Thymus.

Secondary lymphoid organs:

• Spleen
• Lymph nodes
• Tonsils
• Peyer’s Patches of the small intestine.

Or

Primary lymphoid organs are the sites where immature lymphocytes differentiate and become antigen-sensitive mature lymphocytes.

However, secondary lymphoid organs provide site/location for mature lymphocyte & antigen interaction.

Question 8.
Explain what is meant by metastasis. (CBSE 2009)
Answer:
Metastasis. Small pieces of primary tumour break off and are carried to other body parts by the blood or lymph where these form the secondary tumours. This process is called metastasis. So metastasis is the process of transference of cancerous cells from the site of origin to distant parts of the body. The most frequent sites of metastasis are lymph nodes, lungs, long bones, liver, skin and brain. Metastasis is the most feared property of malignant tumours.

Question 9.
A person shows strong unusual hypersensitive reactions when exposed to certain substances present in the air. Identify the condition. Name the cells responsible for such reactions. What precaution should be taken to avoid such reactions?
Answer:
The condition is called allergy. Mast cells are responsible for such reactions. To avoid such reactions, the following precautions must be taken:

• Use of drugs like antihistamine, adrenalin and steroids quickly reduces the symptoms.
• Avoid contact with substances to which a person is hypersensitive.

Question 10.
What are the symptoms of allergic reactions?
Answer:
Symptoms of allergic reactions.
The following are the symptoms of allergies:

• The person may suffer from high fever
• The mucous membrane of the lower part of the respiratory tract gets affected which leads to cough and asthma.
• Reddening of the skin, the appearance of blisters on the skin.
• Accumulation of tissue fluid below the skin.
• Watering of eyes and inability to breathe.
• Sneezing, running nose, etc.

Question 11.
In the metropolitan cities of India, many children are suffering from allergy asthma. What are the main causes of this problem? Give some symptoms of allergic reactions.
Answer:

1. Allergy is the exaggerated (hypersensitive) response of the immune system to certain antigens present in the environment. These certain antigens are called allergens. Our immune system responds to it by releasing histamines and serotonin from mast cells. Common allergens are mites in the dust, pollens and animal dander (material shed from animals),
2. Lifestyle in metro cities is making them sensitive to allergens.
3. The symptoms are sneezing, watery eyes, running nose and difficulty in breathing.

Question 12.
Drugs and alcohol give short-term ‘high’ and long-term ‘damages’. Discuss.
Answer:
Mostly stimulant drugs (caffeine) and alcohol (depressant) give a feeling of intoxication and euphoria for only a brief period soon after use. However, prolonged use for long-term causes permanent damage to vital body parts like liver, kidneys, lungs, cardiovascular system, etc.

Question 13.
List any two adaptive features evolved in parasites enabling them to live successfully on their hosts. (CBSE Delhi 2008)
Answer:
Adaptations of parasites:

1. Presence of adhesive organs or suckers to cling to the host.
2. Loss of unnecessary sense organs.

Question 14.
What is dengue fever? List two symptoms.
Answer:
Dengue fever: Dengue fever is caused by an RNA containing arbovirus of flavivirus group which also causes yellow fever (not found in India). Thus, the virus which causes dengue fever is a mosquito-borne flavi-ribo virus. The virus of dengue fever is transmitted by the bite of Aedes aegypti (mosquito). The incubation period is 3-8 days.

Symptoms:

• Abrupt onset of high fever.
• Severe frontal headache and pain behind eyes which worsens with eye movement.

Question 15.
Why is the structure of an antibody molecule represented as H₂L₂? Name any two types of antibodies produced in humans. (CBSE Delhi 2018C)
Answer:

• The antibody molecule is made up of four peptide chains-two small chains are called light chains and two longer chains are called heavy chains. Hence it is represented as H₂L₂.
• Ig G, Ig A, Ig M. and Ig E are the antibodies produced in humans.

Question 16.
What are the preventive measures of dengue fever? Is there any vaccine available?
Answer:
Prevention and treatment:

1. Mosquitoes and their eggs should be eliminated. Put wire mesh on doors and windows.
2. No specific treatment is available.
3. Symptomatic care including bed rest, intake of adequate fluid and pain killer medicines are recommended.
4. Do not take Aspirin and Aspirin. Give plenty of liquids to the patient.
5. No vaccine for Dengue fever is available.

Question 17.
Differentiate between the roles of B-lymphocytes and T-lymphocytes in generating immune responses. (CBSE Delhi 2019)
Answer:
Role of B-lymphocytes and T-lymphocytes in the immune response:

1. B-cells (B-lymphocytes) and T-cells (T lymphocytes) comprising the immune system are produced in the bone marrow. T-cells differentiate in the thymus.
2. B-lymphocytes produce antibodies in response to foreign substances (antigens) such as pathogens and pollen. Antibodies are immunoglobulins. They are specific for each antigen. There is more than one antibody for an antigen. Antibodies bind antigens but do not destroy them. This is attacked through other mechanisms. Allergens which are weak antigens cause allergy.
3. T-cells respond to pathogens by producing three types of cells: killer T-cells, helper T-cell and suppressor T-cells. T lymphocytes either help B-lymphocytes to produce antibodies or kill the pathogen directly (killer T-cells). Both B- and T-cells produce memory cells when stimulated. These have long lives and form the basis of acquired immunity.

Question 18.
Why is tobacco smoking associated with rising in blood pressure and emphysema? Explain. (CBSE Outside Delhi 2019)
Answer:
Nicotine, an alkaloid present in tobacco, stimulates the adrenal gland to release adrenaline and nor-adrenaline into blood circulation. Both these hormones increase blood pressure and heart rate.

Smoking causes emphysema. Tobacco smoke damages the air sacs (alveoli) of the lungs. Thus surface area for exchange of gases becomes less and disorder emphysema is caused.

Question 19.
Write the scientific names of the causal organisms of elephantiasis and ringworm in humans. Mention the body parts affected by them. (CBSE DeLhi 2012)
Answer:

Name of disease	Causative organism	Organ affected
1. Elephantiasis	(i) Wuchereria bancrofti (ii) Wuchereria malayi Fungi namely	Genital organs, swelling of lower limbs.
2. Ringworm	(i) Microsporum (ii) Trichophyton (iii) Epidermophyton	Skin, nails and scalps.

Human Health and Disease Important Extra Questions Long Answer Type

Question 1.
(i) How and at what stage does Plasmodium enter a human body?
Answer:
Sporozoite stage enters human body aLong with saLiva of female anopheLes mosquito as ii
bites to suck bLood.

(ii) With the help of a flow chart only shows the stages of asexual reproduction in the life cycle of the parasite in the infected human.
Answer:
Asexual phases of the life history of plasmodium in the body of a human

(iii) Why does the victim show symptoms of high fever? (CBSE Delhi 2008, 2013)
Answer:
When the parasite attacks red blood cells, it leads to its rupture with the release of haemozoin, which is a toxin. As the haemozoin is released into blood, symptoms (high fever) of malaria appear.

Question 2.
What is Immune system? Mention the two types of the immune system. (CBSE Delhi 2011)
Answer:
The system which protects our body from pathogens and other foreign invaders is called the immune system. It is of two types.

1. Innate
2. Acquired

Innate immunity is non-specific and is present by birth. It includes physical barriers, physiological barriers, cellular and cytokinin barriers.

Acquired immunity is pathogen-specific and is obtained with experience. It is of two types- Humoral and cell-mediated

Question 3.
Distinguish between B-cells and T-cells.
Answer:
Differences between B-cells and T-cells:

B-cells	T-cells
1. They are produced in cells of bone marrow and remain there and later migrate to lymphoid tissues.	1. They are produced in cells of bone marrow and migrate to the thymus and differentiate under the influence of thymus.
2. These crafts produce plasma cells, once triggered off by the antigens.	2. These cells are responsible for recognising a specific antigen and attack it by releasing chemicals.
3. They are part of a humoral system.	3. They are part of the cell-mediated immune system.
4. They act against viruses and bacteria and do not react against transplants and cancer cells.	4. They act against pathogenic microorganism, organ transplants and cancer cells.
5. No inhibitory effect on the immune system.	5. Suppressor cells inhibit the immune system.

Question 4.
(i) Name the infective stage of Plasmodium which Anopheles mosquito takes in along with the blood meal from an infected human.
Answer:
Gametocytes

(ii) Why does the infection cause fever in humans?
Answer:
Due to the release of haemozoin toxin in the blood.

(iii) Give a flow chart of the part of the life cycle of this parasite passed in the insect. (CBSE (Delhi) 2008, 2011)
Answer:

Question 5.
(i) Why do the symptoms of malaria not appear immediately after the entry of sporozoites into the human body when bitten by female Anopheles? Explain.
Answer:
As the sporozoites enter the human body along with saliva of female anopheles mosquito, these parasites pass through hepatic schizogony in liver cells and erythrocytic schizogony in RBCs. Haemozoin present in unused cytoplasm of RBC is released, followed by the appearance of malarial symptoms. This period is also called the incubation period.

(ii) Give the scientific name of the malarial parasite that causes malignant malaria in humans. (CBSE 2009)
Answer:
Plasmodium falciparum. Causes malignant malaria in human.

Question 6.
Give the scientific name of the parasite that causes malignant malaria in humans. At what stage does this parasite enter the human body? Trace its life cycle in the human body. (CBSE 2009, 2012)
Answer:

• Plasmodium falciparum
• Sporozoites enter the human body along with saliva of the female anopheles mosquito.
• The life cycle of Plasmodium in the human body

Life Cycle of Plasmodium

Question 7.
A 17-year-old boy is suffering from high fever with profuse sweating and chills. Choose the correct option from the following diseases which explains these symptoms and rule out the rest with adequate reasons.
(i) Typhoid
Answer:
If the boy is suffering from typhoid, then he should have sustained high fever (39° to40°C), weakness, stomach pain, constipation and headache. So it cannot be typhoid.

(ii) Viral Fever
Answer:
If the boy is suffering from viral fever, he will suffer from high fever, joint pain, weakness and headache. So it cannot be a viral fever.

(iii) Malaria (CBSE Sample paper 2018-19)
Answer:
If the boy is suffering from malaria, he should have high fever recurring with profuse sweating every three to four days associated with chills and headache. There is a possibility that he is suffering from malaria because high fever associated with chills is possible with malaria.

Question 8.
Medically it is advised to all young mothers that breastfeeding is the best for their newborn babies. Do you agree? Give reasons in support of your answer. (CBSE 2018)
Answer:
Yes, I do agree with the fact that breastfeeding is the best for newborn babies. Mammary glands start producing milk at the end of pregnancy. The milk produced during the initial few days of lactation is called colostrum which contains several antibodies. It helps in developing resistance for newborn baby against diseases. It helps the baby fight off viruses and bacteria. Thus breast milk is packed with a disease-fighting substance that protects newborn babies from illness. Breast milk also naturally contains many of the vitamins and minerals that a newborn requires. It is easily digested as well. There is no constipation, diarrhoea and upset stomach.

Question 9.
Name a human disease, its causal organism, symptoms (any three) and vector, spread by intake of water and food contaminated by human faecal matter. (CBSE 2017)
Answer:

• Amoebic dysentery [Amoebiasis]
• Causal Organism: Entamoeba historlytica, protozoa.

Symptoms:

• Abdominal pain
• Constipation
• Cramps.

Vector: Housefly.

Question 10.
(i) Why is there a fear amongst the guardians that their adolescent wards may get trapped in drug/alcohol abuse?
Answer:
Reasons for alcohol abuse in adolescents:
(a) Curiosity for adventure, excitement and experiment
(b) Social pressure
(c) To escape from stress, depression and frustration
(d) To overcome hardships of life
(e) Unstable or unsupportive family structure, etc.

(ii) Explain ‘addiction’ and dependence’ in respect of drug/alcohol abuse in youth. (CBSE 2017)
Answer:
Addiction is the psychological attachment to certain effects such as euphoria and a temporary feeling of well-being, associated with drugs and alcohol. The addicted person cannot manage him/herself without drug or alcohol.

Dependence: Dependence is the tendency of the body to manifest a characteristic and unpleasant withdrawal syndrome on abrupt discontinuation of a regular dose of drug/alcohol.

Question 11.
What is the basic principle of vaccination? How do vaccines prevent microbial infections? Name the organism from which the hepatitis B vaccine is produced.
Or
Principle of vaccination is based on the property of “memory” of the immune system. Taking one suitable example, justify the statement. (CBSE Delhi 2019)
Answer:
Principle of vaccination is based on the property of ‘memory’ of the immune system.

In vaccination, a preparation of antigenic proteins of pathogens or inactivated/live but weakened pathogens is introduced into the body. The antigens generate a primary immune response by producing antibodies along with forming memory B-cells and T-cells. When the vaccinated person is attacked by the same pathogens, the existing memory B-cells and T-cells recognise the antigen and overwhelm the invaders with massive production of lymphocytes and antibodies. The hepatitis-B vaccine is produced from yeast.

Question 12.
Prior to a sports event blood and urine samples of sportspersons are collected for drug tests.
(i) Why is there a need to conduct such tests?
Answer:
Drugs are consumed by sportspersons to enhance their performance. It is necessary to test the blood and urine of sportspersons to analyse the presence of any performance-enhancing drug.

(ii) Name the drugs the authorities usually look for.
Answer:
Narcotic analgesics, anabolic steroids, diuretics.

(iii) Write the generic names of two plants from which these drugs are obtained. (CBSE Delhi 2016)
Answer:
(a) Cocaine is obtained from Erythroxylum coca
(b) Caffeine is obtained from Coffea arabica and narcotics from Papaver somniferum.

Question 13.
Explain the following terms:
(i) Benign tumour
Answer:
A benign tumour (Non-malignant tumour). Such tumours grow slowly but become quite large. It remains restricted to the place of origin and does not spread to other areas of the body. Most tumours are of this type and do not give rise to cancer.

(ii) Cancerous tumour
Answer:
A cancerous tumour (Malignant tumour): It begins as a small tumour growth at first, grows slowly in the starting and more rapidly later on. The tumour ultimately spreads to the neighbouring tissue like the roots of a tree. Later on, cancerous cells separate off from the original site and migrate through the blood to the other sites and they divide and redivide to form a secondary tumour.

(iii) Metastasis.
Answer:
Metastasis: The stage when the secondary tumour is formed and accumulated by repeated division, is called metastasis. This stage is fatal and causes death sooner or later.

Question 14.
Why cannabinoids are banned in sports and games?
Answer:
Cannabinoids are hallucinogenic chemicals obtained from leaves, resins and inflorescence of Hemp plant, Cannabis sativa. They are used by sportspersons to increase their athletic performance. Intake of cannabinoids results in rapid heartbeat decreased vital capacity of the lung. But their misuse is associated with a number of problems in both sportsmen and sportswomen, e.g. these cause masculinisation, increased aggressiveness, mood swings, abnormal menstrual cycles, enlarged clitoris in sportswomen, while their misuse in sportsmen is known to cause acne, mood swings, reduced testicular size, decreased spermatogenesis, enlarged breasts and prostate gland, dysfunctioning of liver and kidney, etc.

Question 15.
The outline structure of a drug is given below:
1. Which group of drugs does this represent?
2. What are the modes of consumption of these drugs?
3. Name the organ of the body which is affected by the consumption of this drug.

Answer:

1. Cannabinoids.
2. By smoking or oral ingestion.
3. Cannabinoids generally affect the cardiovascular system of the body.

Question 16.
What is cannabis? List its main derivatives.
Answer:
Cannabis: It is the most ancient drug and is obtained from hemp plants.
The following three kinds of drugs are obtained from these plants (Derivative of Cannabis indica):

1. Hashish or Charas is obtained from flowering tops of female plants.
2. Bhang is obtained from dry leaves.
3. Ganja is obtained from small leaves and bracts of inflorescence.

Marijuana is another drug obtained from Cannabis sativa. The common reaction of these drugs is relaxation, euphoria, laughing tendency and rise in blood sugar level.

Question 17.
Why is using tobacco in any form injurious to the health? Explain. (CBSE Delhi 2008, Outside Delhi 2011)
Answer:
Tobacco is injurious to health:

1. Nicotine present in tobacco is toxic and addictive. It causes coronary diseases.
2. Heat irritants and carcinogens cause mouth cancer and lung cancer.
3. Tobacco leads to male infertility.
4. in pregnant women, nicotine causes decreased foetal growth and development.
5. Tobacco addiction often leads to gastric and duodenal ulcers.
6. It is an expensive habit causing staining of teeth and fingers and making breath unpleasant.
7. Swelling of respiratory tract leads to chronic bronchitis.

Question 18.
Give reasons for the following:
(a) Antibody-mediated immunity is called humoral immunity.
Answer:
(a) Antibodies produced by plasma cells are present in the blood, the response is called humoral, immunity response. Thus it is termed humoral immunity.

(b) How is a child protected from a disease for which he/she is vaccinated?
Answer:
The principle of vaccination is based on the property of the ‘memory’ of the immune system. As during vaccination, antigens are introduced in the body. In response to antigens, antibodies are produced in the body against them. They neutralise the pathogen during actual infection.

(c) Name the type of cells the AIDS virus enters after getting into the human body. (CBSE Outside Delhi 2019)
Answer:
HIV enters macrophages. Simultaneously HIV enters T helper- Lymphocytes.

Question 19.
(a) Write the scientific names of the source plants from where opioids and cannabinoids are extracted.
Answer:
Opioids are obtained from the opium plant Papaver somniferous. Cannabinoids are extracted from Cannabis sativa.

(b) Write their receptor sites in the human body. How do these drugs affect human beings? (CBSE Outside Delhi 2019)
Answer:
Receptors of opioids are present on the central nervous system and gastrointestinal tract. They are a depressant and slow down the body functions. Receptors of cannabinoids are present in the brain. They affect the cardiovascular system of the body.

Question 20.
Briefly describe the life history of the malarial parasite.
Answer:

1. Malarial parasite (Plasmodium) completes its life cycle in two hosts., i.e. female anopheles mosquito and humans.
2. Sporozoites are the infective stage.
3. The sporozoites enter the human body, reach the liver through blood and multiply within the liver cells.
4. Such liver cells burst and release the parasites (Cryptomerozoites) into the blood.
5. Then they attack RBCs, multiply and cause their rupture.
6. The rupture of RBCs is associated with the release of a toxin called haemozoin, which is responsible for the high recurring fever and the chill/ shivering and causing malaria.
7. Sexual stages (gametocytes) develop in the red blood cells.
8. The parasite then enters the female Anopheles mosquito along with the blood when it bites the infected person.
9. Further development occurs in the stomach wall of the mosquito.
10. The gametes fuse to form a zygote. It takes the worm-like shape called ookinete as it pierces the wall of the stomach.
11. The zygote undergoes further development in the body of the mosquito to form sporozoites.
12. Sporozoites are transported to and stored in the salivary glands of mosquitoes and are transferred to a human body during the bite of the mosquito.
13. Female mosquito sucks human blood because it requires blood proteins for the development of its eggs.

Question 21.
Describe the effects of drug and alcohol abuse.
Answer:
Effects of drug/alcohol abuse:

1. The immediate effects of drugs/ alcohol abuse are manifested as reckless behaviour, vandalism and violence.
2. Excess doses can lead to coma and death due to cerebral haemorrhage, respiratory and heart failure.
3. A combination of drugs or their intake of alcohol leads to death.
4. The most common warning signals of drug/alcohol abuse include:
   (a) Drop in academic performance.
   (b) Lack of interest in personal hygiene.
   (c) Withdrawal and isolation from family and friends.
   (d) Aggressive and rebellious behaviour.
   (e) Lack of interest in hobbies.
   (f) Change in sleeping and eating habits.
   (g) Fluctuations in weight, etc.

Question 22.
Name the type of immunity that is present at the time of birth in humans. Explain any two ways by which it is accomplished. (CBSE 2008)
Answer:
Innate immunity: It is also called inborn or non-specific immunity. It is the first line of defence. It is composed of the following steps:
1. Anatomic barriers: The skin and mucous membranes secrete certain chemicals which dispose of pathogens. Specific cases of this defence are cited below: The oil and sweat secreted by sebaceous and sudoriferous glands contain lactic acid and fatty acids, which make the skin surface acidic (pH 3 to 5). This does not allow the microorganisms to establish.

2. Physiological barrier: Body temperature, pH and various body secretions like saliva prevent the growth of many pathogenic microorganisms. Pyrogens and interferons aid in fighting infections.

Question 23.
On what basis diagnosis of cancer is made?
Answer:
Diagnosis of cancer:

1. Blood and bone marrow tests are done for increased cell counts in case of leukaemia.
2. Histopathological study or biopsy: In a biopsy, a piece of the suspected tissue cut into thin sections is stained and examined under a microscope by a pathologist.
3. Radiography: X-rays are used to detect cancer of the internal organs
4. Computed tomography: It uses X-rays to generate a three-dimensional internal image of an object.
5. Resonance imaging: Non-ionising radiation and strong magnetic field are used in MRI to accurately detect pathological and physiological changes in the living tissue.
6. Monoclonal antibodies: Antibodies against cancer-specific antigens are also used for the detection of certain cancers.

Question 24.
Explain with the help of sketch the action of HIV in the body. (CBSE Delhi 2011)
Or
Name the cells HIV (Human Immuno Deficiency Virus) gains entry into after infecting the human body. Explain the events that occur in these cells. (CBSE Outside Delhi 2016)
Or
Trace the events that occur in the human body to cause immunodeficiency when HIV gains entry into the body. (CBSE 2011, 2014)
Answer:
The action of HIV in the body. After getting into the body of the person, the virus enters into macrophages where RNA genome of the virus replicates to form viral DNA with the help of the enzyme reverse transcriptase. This viral DNA gets incorporated into the host cell’s DNA and directs the infected cells to produce virus particles. The macrophages continue to produce virus and in this way acts as an HIV factory.

Simultaneously, HIV enters into helper (Th) T-lymphocytes (a type or subset of T-lymphocytes about which you have read above, in the immune system), replicates and produces progeny viruses. The progeny viruses released in blood attack other helper T-lymphocytes. This is repeated leading to a progressive decrease in the number of helper T-lymphocytes in the body of the infected person.

During this period, the person suffers from bouts of fever, diarrhoea and weight loss. Due to the decrease in the number of helper T-lymphocytes, the person starts suffering from an infection due to bacteria such as Mycobacterium, viruses, fungi and even parasite Toxoplasma. The patient becomes so much immunologically deficient and unable to fight against such infections.

The action of HIV in the body cells.

Question 25.
(a) If a patient is advised anti-retroviral drug, name the possible infection he/ she is likely to be suffering from. Name the causative organism.
Answer:
The person may be suffering from AIDS. It is caused by HIV (Human Immunodeficiency Virus).

(b) How do vaccines prevent subsequent microbial infection by the same pathogen?
Answer:
Antibody-provoking agents are called a vaccine. They prevent microbial infection by initiating production of antibodies to act against antigens to neutralise the pathogenic agents during later actual infection.
The vaccine also generates memory B-cells and T-cells that actually recognise the pathogen quickly in case of infection at later stages of life.

(c) How does a cancerous cell differ from a normal cell?
Answer:
Differences between the cancerous cell and normal cell:

Cancerous cells	Normal cells
1. These cells divide in an uncontrolled manner and rate of division is high.	1. These cells divide in a regulated and controlled manner.
2. These cells do not show contact inhibition.	2. These cells show contact inhibition.
3. These cells do not undergo differentiation.	3. These cells undergo programmed differentiation.
4. They have the ability to move in the body fluid and settle at different sites and divide thus show metastasis.	4. These cells don’t show metastasis.

(d) Many microbial pathogens enter the gut of humans along with food. Name the physiological barrier that protects the body from such pathogens. (CBSE Sample Paper 2020)
Answer:
The acid present in the stomach and saliva kills the microbial pathogens that enter along with food.

Question 26.
Write the source and the effect on the human body of the following drugs:
(i) Morphine
(ii) Cocaine
(iii) Marijuana (CBSE Delhi 2011)
Answer:

Name of drug	Source	Effects on the human body
1. Morphine	Opium plant	1. Depresses respiratory centre. 2. Causes fall in blood pressure. 3. Slow heartbeat. 4. Mild hyperglycaemia
2. Cocaine	Natural coca alkaloid obtained from Erythroxylon coca	1. It is a powerful stimulant of the central nervous system (CNS) 2. Increases heartbeat, blood pressure and body temperature.
3. Marijuana	Dried flowers and top leaves of female plant of Cannabis Sativa	1. It causes psychosis 2. Raises blood sugar and increases the frequency of urination

 

Here we are providing Class 12 Biology Important Extra Questions and Answers Chapter 5 Principles of Inheritance and Variation. Important Questions for Class 12 Biology are the best resource for students which helps in Class 12 board exams.

Class 12 Biology Chapter 5 Important Extra Questions Principles of Inheritance and Variation

Principles of Inheritance and Variation Important Extra Questions Very Short Answer Type

Question 1.
Name one trait that does not blend.
Answer:
Sex does not blend.

Question 2.
Give one example of a genetic trait for each of the following in humans:
1. Lethality
Answer:
Lethality: Homozygous sickle cell anaemia.

2. Multiple allelism.
Answer:
Example of Multiple allelism: ABO blood groups.

Question 3.
What for symbols AA and Aa stand?
Answer:

• AA: Homozygous dominant,
• Aa: Heterozygous dominant.

Question 4.
Name the plant that shows incomplete dominance in respect to the colour of its flower.
Answer:
Mirabilis jalapa.

Question 5.
Write the genotypes of a man with blood group A.
Answer:
l^Al^A, l^Al⁰

Question 6.
What is Mendel’s monohybrid ratio for phenotypes?
Answer:
3:1.

Question 7.
Write down Mendel’s dihybrid ratio for phenotypes.
Answer:
9: 3: 3: 1.

Question 8.
Who were the discoverers of Mendelism?
Answer:
Hugo de Vries, Karl Correns, Erich von Tschermak were the rediscoverers of Mendelism.

Question 9.
What are the real determinants of what an organism will become?
Answer:
The complex interaction between genes and their environment really determine what an organism will become.

Question 10.
Name the disorder in humans with the following karyotype:
(a) 22 pairs of autosomes + XO
(b) 22 pairs of autosomes + 21 st chromosome + XY (CBSE Outside Delhi 2019)
Answer:

Karyotype	Name of Disorder
(a) 22 pairs of autosomes + XO	Turner’s syndrome
(b) 22 pairs of autosomes + 21st chromosome + XY	Down’s syndrome (MongoLism inmate)

Question 11.
What wilt is the genetic makeup of an organism which suffers from sickle cell anaemia?
Answer:
Homozygous (Hb^S Hb^S).

Question 12.
Name the type of cross that would help to find the genotype of a pea plant bearing violet flowers. (CBSE Delhi 2017)
Answer:
Test cross.

Question 13.
What term is used for the two chromatids resulting from the interchange of segments during crossing over?
Answer:
Recombinants (cross overs).

Question 14.
Write one example of each of organisms exhibiting
(i) male heterogamety
Answer:
Male heterogamety: Drosophila and humans

(ii) female heterogamety. (CBS£ Delhi 2019 C)
Answer:
Female heterogamety: Birds and some reptiles

Question 15.
A geneticist is interested in study variations and pattern in living being preferred to choose an organism with the short life cycle. Provide a reason. (CBSE Delhi 2015)
Answer:
An organism with a shorter life cycle is helpful in rapid study and analysis of hereditary pattern in many generations, e.g. Drosophila, Neurospora.

Question 16.
Give an example of a human disorder that is caused due to a single gene mutation. (CBSE Delhi 2016)
Answer:
Phenylketonuria.

Question 17.
Write the sex of human having XXY chromosomes with 22 pairs of autosomes. Name the disorder this human suffers from. (CBSE Delhi 2016)
Answer:
The human is male (as Y chromosome is present). He is suffering from Klinefelter’s syndrome

Principles of Inheritance and Variation Important Extra Questions Short Answer Type

Question 1.
State the Mendelian principle which can be derived from a dihybrid cross and not from monohybrid cross.
Or
State Mendel’s Law of Independent Assortment. CBSE Sample Paper 2018-19)
Answer:
From the dihybrid cross, the law of independent assortment can be derived which states that, when two pairs of traits are combined in a hybrid, segregation of one pair of characters is independent of the other pair of characters.

Question 2.
In a cross between two tall pea plants, some of the offsprings produced pure dwarf. Show with the help of Punnett square how this is possible. (CBSE (Delhi) 2013)
Answer:

Question 3.
What is a dihybrid cross?
Answer:
Dihybrid cross. A cross in which two characters are taken into consideration during experimentation, such a cross is called dihybrid cross. A cross between a pea plant with yellow smooth seeds and a pea plant with green, wrinkled seeds is a dihybrid cross.

From the dihybrid cross, it can be derived that each gene is assorted independently of the other during its passage from one generation to the other or Law of independent assortment.

Question 4.
In order to obtain the E, generation, Mendel pollinated a pure breeding tall plant with a pure breeding dwarf plant. But forgetting the F₂ generation, he simply self-pollinated the tall F₁ plants. Why?
Answer:

1. He made crosses to study the pattern of inheritance of a few characters over generations.
2. Initially, he made pure lines.
3. To create a heterozygote or hybrid, he had to cross two different plants (pure lines).
4. To study the inheritance pattern; it is enough if the hybrids are self – pollinated, thus the segregation of factors can be studied.

Question 5.
A cross between a red flower-bearing plant and a white flower-bearing plant of Antirrhinum majus produced all plants having pink flowers. Work out across, to explain how is this possible? (CBSE Outside Delhi 2013)
Answer:

Question 6.
Differentiate gene and allele.
Answer:
Difference between gene and allele:
Allele (allelomorphs) refers to the alternate form of a gene pair present on the same loci in the homologous chromosome, whereas gene is the smallest unit of an organism capable of transmitting genetic information and expressing the same.

Question 7.
In Snapdragon, a cross between true-breeding red-flowered (RR) plants and true-breeding white-flowered (RR) plants showed a progeny of plants with all pink flowers.
(i) The appearance of pink flowers is not known as blending. Why?
Answer:
It is not a case of blending. In this case, R gene was not completely dominant over r gene and this made genotype Rr to distinguish as pink.

(ii) What is this phenomenon known as? (CBSE 2014)
Answer:
Incomplete dominance.

Question 8.
With the help of one example, explain the phenomena of co-dominance and multiple allelism in the human population. (CBSE 2014)
Answer:
In the case of co-dominance, two alleles for a trait are equally expressed.

Example: ABO blood groups are controlled by the gene I. The gene I have three alleles l^A, l^B and l^O. These alleles determine the type of sugar on the RBC surface. Alleles lA and lB are co-dominant and express the AB blood group.

Since there are three different alleles and express themselves on the basis of dominance recessiveness and co-dominance, it is a case of multiple allelism.

Question 9.
The child has a blood group of O. If the father has blood group A and mother has blood group B, work out the genotypes of the parents and the possible genotypes of the other offsprings. (CBSE Outside Delhi, 2015, 2019)
Answer:

1. Genotypes. Man (l^A l^O) Mother l^B l^O and child l^O l^O.
2. The blood group of the future offspring. A type, B type, 0 types and AB type. It is based on the following cross:

Inheritance of blood groups A, B, O, AB

Question 10.
Give examples of sex-linked inheritance in Drosophila. During his studies on genes in Drosophila that were sex-linked T.H. Morgan found F₂ population phenotypic ratios deviated from expected 9: 3: 3: 1. Explain the conclusion he arrived at. (CBSE 2010)
Answer:
Examples of sex-linked inheritance in Drosophila (Morgan’s conclusion).

1. Genes for white eye colour is located in the X-chromosome and Y-chromosome is empty carrying no normal allele for white eye colour.
2. The white-eyed female possesses a gene for white eye colour (W) on both of its X-chromosomes.
3. The white-eyed males receive X-chromosome with (W) gene from mother and (Y) from father with no gene.
4. The daughter receives one X-chromosome with (W) gene from mother and one X-chromosome with dominant (W+).

Question 11.
Briefly explain XX-XO (a type of sex determination).
Answer:
In the case of roundworms, true bugs, grasshoppers and cockroaches the females have two sex chromosomes XX, whereas the males have only one X-chromosome. The male has no second chromosome thus designated as XO. The sex ratio of 1: 1 is produced as shown in the figure below.

XX-XO determination of sex in the cockroach.

Question 12.
Explain the mechanism of ‘sex determination’ in birds. How does it differ from that of human beings? (CBSE Delhi 2018)
Answer:
Sex determination is of ZW-ZZ type in birds.
In this type, the males are homogametic and have ZZ sex chromosomes, and females are heterogametic with ZW pair of sex chromosomes.

In human beings, the chromosomal mechanism of sex determination is of XX- XY type. The human male is heterogametic and has XY sex chromosomes, whereas the human female is homogametic with XX sex chromosomes.

Question 13.
Write a note on ZO-ZZ type of sex determination.
Answer:
In case of ZO-ZZ type of sex determination the female produces two types of eggs. The one-half of eggs is with Z-chromosome and the other half without Z-chromosome. The male has homomorphic sex chromosomes and is homogametic. It forms only one kind of sperms each with Z-chromosome. On fertilisation by a sperm with Z-chromosome, the Z-containing egg gives rise to male offspring ZZ and Z- lacking egg produces female offspring ZO. Such type of sex determination is found in the case of butterflies and moths.

Question 14.
Give an example of an autosomal recessive trait in humans. Explain its pattern of inheritance with the help of a cross. (CBSE Delhi 2016)
Answer:
Autosomal recessive trait. Sickle-cell anaemia is caused by autosomal recessive trait. The disease is controlled by a single pair of alleles Hb^A and Hb^S. Only the homozygous individuals for HbsHbs show the disease. The heterozygous individuals are carriers (Hb^A Hb^s)

Question 15.
How would you find the genotype of a tall pea plant bearing white flowers? Explain with the help of a cross. Name the types of the cross you would use. (CBSE Delhi 201i 5)
Answer:
In order to find the genotype of a given plant, one has to breed it with plenty of oic recessive individual. It is called test CRC is. Tall and white plant TTww or Ttww / is crossed with dwarf white plant ttww TTww x ttww

(All tall white plants indicate that the genotype is TTww)

This ratio indicates that the genotype is Ttww

Depending on the resuLt we can determine the genotype of the flower.

Question 16.
How is polygenic inheritance different from pleiotropy? Give one example of each.
Answer:

polygenic inheritance	pleiotropy
It is a type of inheritance in which. a single dominant gene contributes a part of the trait. Thus dominant alleles have a cumulative effect.	It is a condition in which a single gene influence more than one trait.
Example: 1. Cob length in maize 2. Skin colour in human	Example: 1. In Drosophila, white eye mutant causes depigmentation in many parts of the body. 2. Sickle cell anaemia

Question 17.
Why is it not possible to study the pattern of inheritance of traits in human beings, the same way as it is done in pea plant? Name the alternate method employed for such an analysis of human traits.
Answer:

1. Control cross cannot be performed in human as in other organisms.
2. The generation time is long. Pedigree analysis is the alternative method to study the inheritance of human traits in several generations.

Question 18.
A man with blood group A married a woman with a B group. They have a son with AB blood group and a daughter with blood group 0. Work out the cross and show the possibility of such inheritance. (CBSE Delhi and Outside Delhi 2008)
Answer:

Blood groups of progeny A, B, AB and O.

Question 19.
A haemophilic father can never pass the gene for haemophilia to his son. Explain. (CBSE Delhi 2016)
Answer:
Haemophilia is a sex-linked recessive disorder where X chromosome carries the defective haemophilic gene and Y chromosome is healthy. And son inherits only the Y chromosome from his father which is not carrying the gene for haemophilia. Therefore, the haemophilic father can never pass haemophilia to his son.

Principles of Inheritance and Variation Important Extra Questions Long Answer Type

Question 1.
Study the given pedigree chart and answer the questions that follow:
1. Is the trait recessive or dominant?
Answer:
Dominant.

2. Is the trait sex-linked or autosomal?
Answer:
Autosomal.

3. Give the genotypes of the parents shown in generation I and their third child is shown in generation II and the first grandchild shown in generation III. (CBSE Sample Paper 2018-19)

Answer:
The genotype of parents in generation I – Female: aa and Male: Aa
The genotype of a third child in generation II-Aa Genotype of the first grandchild in generation III – Aa

Question 2.
Haemophilia is a sex-linked recessive disorder of humans. The pedigree chart given below shows the inheritance of Haemophilia in one family.

Study the pattern of inheritance and answer the questions given.
1.Give all the possible genotypes of the members 4, 5 and 6 in the pedigree chart.
2. A blood test shows that the individual 14 is a carrier of haemophilia. The member numbered 15 has recently married the member numbered 14. What is the probability that their first child will be a haemophilic male?
(CBSE 2009, CBSE Sample Paper 2018-19)

Answer:

1. Genotypes of member 4 – XX or XX^h Genotypes of member 5 – X^hY Genotypes of member 6 – XY
2. The probability of first child to be a haemophilic male is 50%.

Question 3.
Mention the advantages of selecting a pea plant for the experiment by Mendel.
Answer:
Advantages of selecting pea plant as experimental material:

Mendel selected pea plant (Pisum sativum) because:

1. Many varieties were available with observable alternative forms for a trait or a characteristic.
2. Peas normally self-pollinate; as their corolla completely encloses the reproductive organs until pollination is complete.
3. It was easily available.
4. It has pure lines for experimental purpose, i.e. they always breed true.
5. It has contrasting characters. The traits were seed colour, pod colour, pod shape, flower shape, the position of flower, seed shape and plant height.
6. Its life cycle was short and produced a large number of offsprings.
7. The plant can be grown easily and does not require care except at the time of pollination.

Question 4.
Differentiate between the following:
(i) Dominance and recessiveness
Answer:
Differences between dominance and recessiveness:

Dominance	Recessiveness
(1) Dominant gene or factor is able to express itself even in the presence of its recessive allele.	(1) Recessive gene or factor is unable to express itself in the presence of dominant allele.
(2) It expresses itself because it forms complete polypeptide or enzyme for expressing its effect.	(2) The recessive gene forms an incomplete or defective polypeptide or enzyme thus fails to express its effect.

(ii) Homozygous and heterozygous
Answer:
Differences between homozygous individual and a heterozygous individual:

homozygous individual	heterozygous individual
(1) In a homozygous individual (homo-zygote) the two genes for a particular character are identical (TT) or (tt).	(1) The heterozygous individual (hetero zygote) possesses contrasting genes of a pair çrt).
(2) They form identical gametes for a particular character.	(2) They form dissimilar gametes for a particular character.
(3) They breed true for a specific trait.	(3) They do not breed true.

Question 5.
Explain the law of dominance using a monohybrid cross.
Answer:
Law of Dominance. According to this law, when two factors of a character are unlike, one of them will manifest in the body and is called dominant while the other remains hidden and is termed recessive factor.

The law can be well explained by the monohybrid cross by studying the following crosses:
(i) Pure tall = TT, Hybrid tall = Tt

Gametes of TT parent = \(\frac { 1 }{ 2 }\)T + \(\frac { 1 }{ 2 }\)T
Gametes of Tt parent = \(\frac { 1 }{ 2 }\)T + \(\frac { 1 }{ 2 }\)t

The 50% are pure tall and 50% hybrid tall. Then pure tall plants will produce 100% tall in F₂ generation and hybrid plants will produce in the ratio of 1: 2: 1 in the F2 generation.

(ii) When the cross is made between pure tall and pure dwarf, we get results as follows (Fig.).

A Punnett square used to understand a typical monohybrid cross conducted by Mendes between true-breeding tall plants and true-breeding dwarf plants

Question 6.
Define and design a test cross.
Answer:
Test Cross: It is a cross between an organism of an unknown genotype and a homozygous recessive organism.

Results of a Test Cross: If the test cross yields offspring of which 50% show the dominant character and 50% show the recessive character, i.e. F1 ratio is 1: 1, the individual under test is heterozygous (see fig.). This is so because the individual showing the recessive trait (say white coat colour in the guinea pig, dwarf size in pea plant) must have received one recessive allele (b in a guinea pig, t in pea plant) from each parent.

Genetics of a test cross

If all the offspring of the test cross show the dominant trait, the individual being tested is homozygous dominant with genotype BB for a guinea pig and TT for pea plant (fig.).

Question 7.
When a cross is made between a tall plant with yellow seeds (TtYy) and tall plant with green seeds (Ttyy), what proportions of phenotype In the offspring could be expected to be
(i) tall and green
(ii) dwarf and green?
Answer:

Cross between a tall plant with yellow seeds

Question 8.
Differentiate back cross and test cross.
Answer:
Differences between the back cross and test cross:

Back cross	Test cross
1. It is the hybridisation process between F1 progeny and one of its parents.	1. It represents the hybridisation between F1 progeny with the homozygous recessive parent.
2. The ratio of F2 progeny maybe 1: 1.	2. The ratio of F2 progeny is 1:1.
3. It is used to develop a good hybrid particularly through recurring back cross.	3. It is used to testify the genotype of the F1 progeny.

Question 9.
Differentiate incomplete dominance and codominance.
or
Explain the following terms with an example:
(i) Codominance
(ii) Incomplete dominance (CBSE Outside Delhi 2008; Delhi 2011, 2019)
Answer:
Differences between incomplete dominance and codominance:

Incomplete Dominance	Codominance
(1) Effect of one of the two alleles is more prominent.	(1) The effect of both the alleles is equally prominent.
(2) It produces a fine mixture of the expression of two alleles.	(2) There is no mixing of the effect of the two alleles.
(3) The effect in hybrid is intermediate of the expression of the two alleles, e.g. pink coloured snapdragon obtained as a result of cross-pollination between red and white snapdragon flowers.	(3) Both the alleles produce their effect independently, e.g. IA and lB, HbS and HbA.

Question 10.
(i) Why is the human ABO blood group gene considered a good example of multiple alleles?
Answer:
A B O blood groups are controlled by a single gene: (I) The plasma membrane of the red blood cells has sugar polymers that protrude from its surface and is controlled by the gene. The gene (I) has three alleles l^A, l^Band l^O. Presence of more than two types of alleles at the same locus governing the same character is called multiple alleles.

(ii) Work out across up to F₂ generation only, between a mother with blood group A (Homozygous) and the father with blood group B (Homozygous). Explain the pattern of inheritance exhibited. (CBSE (Delhi) 2013)
Or
Describe the mechanism of a pattern of inheritance of ABO blood groups in human. (CBSE 2011)
Answer:
Patterns of inheritance of the ABO blood group.

F₁ generation. All with blood group AB. It is a case of co-dominance.

Question 11.
(i) What is polygenic inheritance? Explain with the help of a suitable example, (ii) How are pleiotropy and Mendelian pattern of inheritance different from the polygenic pattern of inheritance? (CBSE Outside Delhi 2016)
Or
Certain phenotypes in the human population are spread over a gradient and reflect the contribution of more than two genes. Mention the term used for the type of inheritance. Describe it with the help of an example in the human population. (CBSE Sample Paper 2019-20)
Answer:
(i) Polygenic inheritance. It is a type of inheritance controlled by three or more genes in which the dominant alleles have a cumulative effect. Each dominant allele expresses a part or unit of a trait. It is also called quantitative inheritance or multiple factor inheritance. The genes involved in such kind of inheritance are termed polygenes.

Examples:

1. Kernel colour in wheat
2. Cob length in maize
3. Skin colour in human
4. Human intelligence Human Skin Colour. It is caused by the pigment melanin.

The quantity of melanin is due to three pairs of polygenes (A, B and C). The genotype of black will be (AA BB CC) and white will have (aa bb cc). Marriage between two such persons will show variations. In progeny (Aa Bb CC) there will be 7 types of phenotypes i.e. very dark, 6 dark, 15 fairly dark, 20 intermediates, 15 family light, 6 light and have very light.

(ii) How are pleiotropy and Mendelian pattern of inheritance different from the polygenic pattern of inheritance? (CBSE Outside Delhi 2016)
Answer:

1. Pleiotropy and Mendelian pattern of inheritance: In the case of pleiotropy one gene has an effect on two on more traits. One effect is more evident in the case of one trait (major effect) and less evident in the case of others (secondary effect). The mendelian pattern of inheritance is monogenic.

2. In pleiotropism and monogenic inheritance no intermediates are produced and show discontinuous variations in the expression of a trait. Intermediates are quite common in polygenic inheritance and produce continuous variations in the expression of a trait.

Question 12.
(i) Write the scientific name of the organism Thomas Hunt Morgan and his colleagues worked with for their experiments. Explain the correlation between linkage and recombination with respect to genes as studied by them.
Answer:
Thomas Hunt Morgan and his colleagues worked with Drosophila melanogaster. They carried out several dihybrid crosses in Drosophila to study gens that were sex-linked.

Morgan and his group knew that the genes were located on the X chromosome and noticed that when the two genes in a dihybrid cross were situated on the same chromosome, the proportion of parental gene combinations were much higher than the non-parental type.

Morgan attributed this due to the physical association or linkage of th< two genes. He coined the term links to describe this physical associate of genes on a chromosome and t/ term recombination to describe t generation of non-parental age combination. Morgan and his also found that even when genes w grouped on the same chromos or some genes were very tightly linked, they showed very low recombine while others were loosely linked.

(ii) How did Sturtevant explain gene mapping while working with Morgan? (CBSE Delhi 2018)
Answer:
Alfred Sturtevant was Morgan’s student. He used the frequency of recombination between gene pairs on the same chromosome as a measure of the distance between genes and ‘mapped’ their position on the chromosome. Today genetic mappings are extensively used as a starting point in the sequencing of the whole genomes.

Question 13.
What is recombination? Discuss the applications of recombination from the point of view of genetic engineering.
Answer:
Recombination refers to the generation of a new combination of genes which is different from the parental types. It is produced due to crossing over that occurs during meiosis prior to gamete formation.

Applications of recombination:

1. It is a means of introducing new combinations of genes and hence new traits.
2. It increases variability which is useful for natural selection under changing environment.
3. It is used for preparing linkage chromosome maps.
4. It has proved that genes lie in a linear fashion in the chromosome.
5. Breeders have to select small or large population for obtaining the required cross-overs. For obtaining cross-overs between closely linked genes, a very large population is required.
6. Useful recombinations produced by crossing over are picked up by breeders to produce useful new varieties of crop plants and animals. Green revolution and white revolution were implemented using the selective recombination technique.

Question 14.
How is sex determined? (CBSE Delhi 2015)
Answer:
Determination of the sex of the child. Sex chromosomes determine sex in human beings. In males, there are 44+XY chromosomes, whereas in female there are 44+XX chromosomes. Here X and Y chromosomes determine sex in human beings.

Two types of gametes are formed in male, one type is having 50% X-chromosome, whereas another type is having Y-chromosome. In a female, gametes are of one type and contain X-chromosome. Thus females are homogametic and males are heterogametic. If male gamete having Y-chromosome (endosperm) undergoes fusion with female gamete having X-chromosome, the zygote will have XY chromosome and this gives rise to a male child.

If male gamete having X-chromosome (gymnosperm) undergoes fusion with female gamete having X-chromosome, the zygote will be having XX-chromosome and this gives rise to the female child.

Genetics of sex in human beings. The letter A represents autosomes.

Question 15.
Both haemophilia and thalassemia are blood-related disorders in human. Write their causes and the difference between the two. Name the category of genetic disorder they both come under. (CBSE Delhi 2017)
Answer:
Both haemophilia and thalassemia are Mendelian disorders:

• Haemophilia is a sex-linked recessive disorder. The gene for haemophilia is located on X-chromosome. The gene passes from a carrier female to her son.
• Thalassemia is an autosomal-linked recessive disease.
• It occurs due to either mutation or deletion resulting in the reduced rate of synthesis of one of the globin chains of haemoglobin.
• Difference between Haemophilia and Thalassemia. In haemophilia, clotting is affected, i.e. there can be a non-stop bleeding even after a minor cut.
• In Thalassemia anaemia is the characteristic of this disease. It is caused by faulty haemoglobin synthesis.

Question 16.
Differentiate male and female heterogamety. (CBSE Delhi 2015, 2019 C)
Answer:
Differences between male and female heterogamety:

Male heterogamety	female heterogamety
(1) Mate heterogamety refers to the phenomenon, where mates produce two (more than one) types of sperms.	(1) Female heterogamety refers to the phenomenon, where females produce two (more than one) types of ova.
(2) Sex of the individual is determined by the type of sperm fertilising the ovum.	(2) Sex of the individual is determined by the type of ovum that is fertilisers.
(3) XX female XY male	(3) ZZ male and ZW female.

Question 17.
Why Drosophila has been used extensively for genetical studies? (CBSE 2014, 2019 C)
Answer:
Advantages of using Drosophila as genetic material:
Drosophila is a very useful organism for genetical experiments because:

1. A very large number of offsprings are produced after each mating.
2. It can be cultured in large number in laboratory and animals can be easily examined under a hand lens.
3. Its life cycle is very short and is completed in 10-12 days. A new generation can be obtained every two weeks.
4. It has four pairs of chromosomes all different in size and easily distinguishable.
5. They produce numerous variants.
6. It has heteromorphic (XY) chromosomes in the male.
7. Female Drosophila flies can be easily differentiated from the males by the large body size and presence of ovipositor in the abdomen.

Question 18.
Mendel published his work on the inheritance of characters in 1865, but it remained unrecognised till 1900. Give three reasons for the delay in accepting his work. (CBSE Delhi 2014)
Answer:
Mendel’s work published as “Experiments on plant hybridisation” remained unnoticed and unappreciated for some 34 years due to:

1. Limited circulation of the “Proceedings of Brunn Natural Science Society” in which it was published.
2. He could not convince himself about his conclusions being universal since Mendel failed to reproduce the results on Hawkweed (Hieracium) undertaken on the suggestion of Naegeli. It was due to non-availability of pure lines.
3. Absence of aggressiveness in his personality.
4. The scientific world was being rocket^ at that time by Darwin’s theory c}f Natural Selection.

Question 19.
Compare in any three ways the chromosomal theory of inheritance as proposed by Sutton and Boveri with that of experimental results on pea pie int presented by Mendel. (CBSE Delhi 2019)
Answer:

Sutton and Boveri	Mendel
(1) Chromosomes occur in pairs.	(1) Factors occur in pairs.
(2) Chromosomes segregate during gamete formation such that only one of each pair is transmitted to a gamete.	(2) Factors segregate during gamete formation stage and only one of each pair is transmitted to a gamete.
(3) Independent pairs of chromosomes segregate independently of each other.	(3) One pair of factors segregate independently of another pair.

Question 20.
(a) Explain linkage and recombination as put forth by T.H. Morgan based on his observations with Drosophila melanogaster crossing experiment.
(b) Write the basis on which Alfred Sturtevant explained gene mapping. (CBSE Delhi 2019)
Answer:
(a) Linkage and recombination:

• Morgan is called the father of experimental genetics.
• Morgan used Drosophila for experiments of genetics.
• Linkage: It is the phenomenon of certain genes staying together during inheritance through several generations without any change or separation of these being present on the same chromosome. The two genes do not segregate independently of each other. So, F₂ generation deviates significantly from 9:3:3:1.
• Recombination: Loosely linked genes show a higher frequency of recombinant frequency which is around 37.2%. Tightly linked genes tend to show fewer recombinant frequency which is around 1.3%.

(b) Morgan’s student Alfred Sturtevant used the frequency of recombination between gene pairs on the same chromosome as a measure of the distance between genes and mapped their position on a chromosome.

Question 21.
ExplaIn how a test cross can be conducted to distinguish between a homozygous and heterozygous dominant genotype. What is the test cross? How can it decipher heterozygosity of a plant? (CBSE Delhi 2016)
Or
How will you find out whether a given plant is homozygous dominant? (CBSE 2008)
Or
You are given a tall pea plant and asked to find its genotype. How will you find it? (CBSE Outside Delhi 2019)
Answer:
Test Cross. When an individual is crossed to recessive parent it is called a test cross. The results can be easily analysed. If you follow the monohybrid cross where the FT is test crossed, a ratio of 1:1 will be obtained. On the same basis, you can work out that in a dihybrid case, the test cross ratio will be 1:1:1:1. Test cross can also be used for another purpose.

You must have understood by now that the homo and heterozygous genotypes for a dominant trait cannot be differentiated because they show the same phenotype. If we put them through a test cross, you will see that all homozygous dominant combinations will breed true but heterozygous genotypes will follow the segregation.

A test cross can be conducted to differentiate between a homozygous and heterozygous dominant genotype.

Question 22.
Explain the law of independent assortment with a dihybrid cross. (CBSE Outside Delhi, 2013, 2014)
Answer:
Law of independent assortment: According to this law, the factors of different pairs of contrasting characters do not influence each other. They are independent of one another in their assortment to form a new combination during gamete formation. Dihybrid cross. A cross in which two characters are taken into consideration during experimentation, such a cross is called dihybrid cross.

A cross between a pea plant with yellow smooth and a pea plant with green, wrinkled seeds is considered. Explanation. When a cross is made between pea plant having yellow smooth seeds (YYSS) and a pea plant with green wrinkled seeds (yyss). At the time of cross-pollination, yellow smooth (YYSS) produces gametes with genes (YS) and green wrinkled will produce gametes with gene (ys). Gametes unite at random. The seeds obtained when placed in the soil will grow to form plants and produce seeds which are yellow smooth (YySs) because yellow and smooth characters are dominant over green and wrinkled. These are called plants of F₁ generation.

When plants of F₁ generation are allowed to self-pollinate gametes formed YS, Ys, yS and ys by meiosis, they unite at random forming seeds. The plants thus obtained are called F₂ generation. They are Yellow smooth (YYSS, YySS, YySs, YYSs); yellow wrinkled (YYss, Yyss), green smooth (yySS, yySs) and green wrinkled (yyss) in the ratio of 9: 3: 3: 1. The result of a dihybrid cross can be shown in Fig. on the chequerboard.

Result of a dihybrid cross.

From the above dihybrid cross, it can be derived that each gene is assorted independently of the other during its passage from one generation to the other or law of independent assortment is justified.

Question 23.
In four o’clock plants, red colour (R) is incompletely dominant over white (r), the heterozygous having pink colour. What will be the offspring in a cross between a red flower and a pink flower? (CBSE Outside Delhi, 2013)
Answer:

1. In the monohybrid cross, red is incompletely dominant over white.
2. Red flowered plants have genotype RR and white-flowered plants have genotype rr.
3. Pink flowers have a genotype Rr.
4. Red flowering plants will form gametes with R genes and pink flowers will produce two types of gametes with R gene and r gene.
5. Arrangement of gametes in chequerboard.

Question 24.
Explain the pattern of inheritance of haemophilia in humans. Why is the possibility of a human female becoming a haemophilic extremely rare? Explain. (CBSE Delhi, 2008; Outside Delhi 2011)
Or
Why is human female rarely haemophilic? Explain how do haemophilic patients suffer? (CBSE Outside Delhi 2013)
Answer:
A pattern of inheritance of haemophilia:

1. It is the sex-linked recessive trait which is known as bleeder’s disease because the exposed blood does not readily clot due to deficiency of plasma thromboplastin (haemophilia B/ Christmas disease) or Antihaemophilia globulin (haemophilia A)
2. The defect has been inherited in the family of British Crown through Queen Victoria.
3. In females, haemophilia appears when both the sex chromosomes carry its recessive gene, X^h X^h. Such females die before birth.
4. A woman having a single allele of the trait appears normal but is a carrier of the disease XX^h
   
5. For sex-linked genes, human males are hemizygous. Therefore, X^h Y is haemophilic.
6. Marriage between haemophilic male and carrier female produces haemophilic sons (X^hY, 50%), normal sons (XY, 50%), carrier daughters (XX^h, 50%) and haemophilic daughters (X^hX^h, 50%, die before birth).
7. Haemophilic man (X^hY) and normal woman (XX) produce carrier girls (XX^h) and normal boys (XY).
   
8. Marriage between carrier woman and normal man produce 50% carrier girls (XX^h), 50% normal girls (XX), 50% normal boys (XY) and 50% haemophilic boys (X^hY).
   
   Sons- 50% normaL 50% heamophitic
   Daughters- 50% normaL 50% camer
9. The possibility of a female becoming haemophilic is very rare because the mother of such a female has to be at least a carrier and father should be haemophilic.

Question 25.
A colourblind child is born to a normal couple. Work out a cross to show how is it possible. Mention the sex of this child. (CBSE Delhi 2014, 2016)
Answer:
(a) Colourblindness is an X-linked recessive disease

So, the sex of the child is male.

Question 26.
1. How does a chromosomal disorder differ from a Mendelian disorder?
2. Name any two chromosomal aberra¬tion associated disorders.
3. List the characteristics of the disorders mentioned above that help in their diagnosis. (CBSE 2010)
Or
How does gain or loss of chromosome(s) take place in humans? Describe one example each of chromosomal disorder along with the symptoms involving an autosome and a sex chromosome. (CBSE Sample Paper 2019-20)
Answer:
1. Mendelian disorders are mainly determined by alteration or mutation in a single gene. These disorders are transmitted to the offspring on the basis of Mendelian inheritance, e.g. haemophilia, sickle cell anaemia. Chromosomal disorders are caused due to absence or excess or abnormal arrangement of one or more chromosomes. They are caused due to failure of segregation of chromatids during cell division or due to polyploidy. e.g. Down’s syndrome, Klinefelter syndrome.

2. Chromosomal aberration associated disorders.
(a) Down’s syndrome
(b) Klinefelter syndrome.

3. (a) Down’s syndrome. It is caused due to an additional copy of chromosome number 21 (Trisomy).
Symptoms: Short statured body, small rounded head, furrowed tongue, partially open mouth.

(b) Klinefelter syndrome. It is caused due to an additional copy of X-chromosomes (47 chromosome XXY).
Symptoms. Overall masculine development but the development of breast also occurs. These individuals are sterile.

Question 27.
A true-breeding pea plant, homozygous for inflated green pods (FFGG) is crossed with another pea plant with constricted yellow pods (ffgg). What would be the phenotype and genotype  F₁ and F₂ genotype? Give the phenotype ratio of F₂ generation. (CBSE Delhi 2008)
Answer:

Question 28.
A true-breeding pea plant homozygous for axial violet flowers (AAW) crossed with another pea plant with terminal white flowers (aaw).
(i) What would be phenotype and genotype of F₁ and F₂ generations
Answer:

(ii) Give the phenotype ratio of F₂ generations. (CBSE Delhi. 2008)
Answer:

Question 29.
A child suffering from Thalassemia is born to a normal couple. But the mother is being blamed by the family for delivering a sick baby.
(i) What is Thalassemia?
Answer:
Thalassemia: It is an autosomal recessive blood disease that appears in children of two unaffected carriers, heterozygote parents. The defect occurs due to mutation or deletion of the genes controlling the formation of globin chain (commonly a and P) of haemoglobin. Imbalanced synthesis of globin chains of haemoglobin causes anaemia. Thalassemia is of three types a, p, and 8.

(ii) How would you counsel the family not to blame the mother for delivering a child suffering from this disease? Explain.
Answer:
I would explain to the people around that this disease can be caused due to the presence of a defective gene in both the parents or it may be caused due to certain changes with the genetic setup.

(iii) List the values your counselling can propagate in the families. (CBSE Delhi 2013)
Answer:
People had a good understanding and had to realize the situation. They become supportive and made joint efforts to help the patients.

Question 30.
In a dihybrid cross, white-eyed, yellow-bodied female Drosophila was crossed with red-eyed, brown-bodied male Drosophila. The cross produced 1.3 per cent recombinants and 98.7 progeny with parental type combinations in the F2 generation. Analyse the above observation and compare with the Mendelian dihybrid cross. (CBSE Sample Paper 2018-19)
Answer:
Morgan observed that the two genes did not segregate independently of each other and the F2 ratio deviated vary significantly from the 9:3:3:1 ratio.

He attributed this to physical association or linkage of two genes and coined the term linkage and the term recombination to describe the generation of non-parental gene combinations.

Morgan and his group found that even when the genes are grouped on the same chromosome, some genes are very tightly linked (show very low recombination) while others were loosely linked (showed higher recombination). in the Mendelian dihybrid cross, the phenotypes round, yellow; wrinkled, yellow; round, green and wrinkled, green appeared in the ratio 9:3:3:1.

Wrinkled, yellow and round, green is possible because the distance between two genes is more. Therefore, recombination of parental type is possible.

Question 31.
Aneuploidy of chromosomes in human beings results in certain disorders. Draw out the possibilities of the karyotype in common disorders of this kind in human beings and its consequences in individuals. (CBSE Sample Paper 2018-19)
Or
A doctor after conducting certain tests on a pregnant woman advised her to undergo M.T.P., as the foetus she was carrying showed trisomy of 21st chromosome.
(a) State the cause of trisomy of the 21 st chromosome.
Answer:
(a) Down’s syndrome, Turner’s syndrome, Klinefelter’s syndrome are common examples of Aneuploidy of chromosomes in human beings.

• Down’s syndrome results in the gain of the extra copy of chromosome 21- trisomy.
• Turner’s syndrome results due to the loss of an X chromosome in human females- XO monosomy.
• Klinefelter’s syndrome is caused due to the presence of an additional copy of X- chromosome resulting in XXY condition.

(b) Why was the pregnant woman advised to undergo M.T.P. and not to complete the full term of her pregnancy? Explain. (CBSE Delhi 2019 C)
Answer:
Down’s Syndrome: The affected individual is

• short statured with small round head furrowed tongue and partially open mouth
• Palm is broad with characteristic palm crease
• Physical, psychomotor, and mental development is retarded.

Klinefelter’s Syndrome: The affected individual is

• a male with development of breast, i.e. Gynecomastia
• Such individuals are sterile.

Turner’s Syndrome: The affected individual shows the following characters:

• Females are sterile as ovaries are rudimentary
• lack of other secondary sexual characters

Very Important Figures:

XX-XO determination of sex in the cockroach.

Formation of recombinant as well as non-recombinant (parental type) gametes.
Forms of chromosomal mutations.

Answer:

S. No Blood groups of  parents	Blood groups possible in children	Blood groups not possible in children
1. O × O	O	A, B, AB
2. O × A	O, A	B, AB
3. O × B	O, B	A, AB
4. O × AB	A, B	O, AB
5. A × A	O, A	B, AB
6. A ×  B	O, A, B, AB	None
7. A  ×  AB	A, B, AB	O
8. B ×  B	O, B	A, AB
9. B  ×  AB	A, B, AB	O
10. AB  × AB	A, B, AB	O

Here we are providing Class 12 Biology Important Extra Questions and Answers Chapter 2 Sexual Reproduction in Flowering Plants. Important Questions for Class 12 Biology are the best resource for students which helps in Class 12 board exams.

Class 12 Biology Chapter 2 Important Extra Questions Sexual Reproduction in Flowering Plants

Sexual Reproduction in Flowering Plants Important Extra Questions Very Short Answer Type

Question 1.
Name the component cells of the egg apparatus in an embryo sac?
Answer:
One egg or oosphere and two synergids.

Question 2.
Name the part of gynoecium that determines the compatible nature of pollen grain?
Answer:
Stigma

Question 3.
Name the common function that cotyledons and nucellus perform?
Answer:
Nourishment (embryo by cotyledons and embryo sac by nucellus).

Question 4.
Complete the following flow chart. Pollen grain?
Answer:

A = Generative cell.

Question 5.
Name the structure formed the development of microsporangia?
Answer:
Pollen sac.

Question 6.
Why pollen grains can be preserved as fossils?
Answer:
It is due to the presence of sporopollenin present in exine.

Question 7.
Indicate the stage where meiosis occurs (1, 2 or 3) in the flow chart.

Answer:
1 = Meiosis

Question 8.
State the reason why pollen grains lose their viability when the tapetum in the anther is malfunctioning?
Answer:
As tapetum provides nutrition, the pollen loses its viability due to non-availability of nutrition.

Question 9.
In a case of polyembryony, if an embryo develops from the synergid and another from the nucellus, which is haploid and which is diploid?
Answer:
Synergid embryo is haploid (n) and nucellus embryo is diploid (2n).

Question 10.
Can an unfertilised, apomictic embryo sac give rise to a diploid embryo? If yes, then how?
Answer:
Yes, if the embryo develops from the cells of nucellus or integument, it will be diploid.

Question 11.
Why is an embryo sac diploid in agamospermy?
Answer:
The embryo sac is diploid because it is formed without reductional division.

Question 12.
How do drones develop in honeybees? Name the process.
Answer:
In honeybees, unfertilised eggs develop the drones. They are sterile male. The process is called parthenogenesis.

Question 13.
What is chalaza?
Answer:
Chalaza is the part of nucellus from where integuments arise.

Question 14.
What do you mean by agamospermy?
Answer:
Agamospermy is the formation of embryos by asexual reproductive processes.

Question 15.
What types of pollution occur in Vallisneria? (CBSE Delhi 2019)
Answer:
By water (Hydrophily)

Question 16.
Name a few plants which show viviparous germination?
Answer:
Rhizophora and Sonneratia.

Question 17.
A bilobed, dithecous anther has 100 microspore mother cells per microsporangium. How many male gametophytes this anther can produce? (CBSE 2010)
Answer:
100 × 4 = 400.

Question 18.
An anther with malfunctioning tapetum often fails to produce viable male gametophyte? Give one reason? (CBSE 2010)
Answer:
Tapetum provides nutrition. In the case of malfunctioning tapetum, due to absence of nutrition, it fails to produce viable gametophyte.

Question 19.
How many pollen grains and ovules are likely to be formed in the anther and the ovary of an angiosperm bearing 25 microspore mother cells and 25 megaspore mother cells respectively? (CBSE Sample Paper 2018-19)
Answer:
25 Microspore mother cells will form 100 pollen grains, whereas 25 megaspore mother cells will form 25 ovules respectively.

Question 20.
In the case of polyembryony, an embryo A develops from the synergids and the embryo B develops from the nucellus. State the ploidy of embryo A and B? (CBSE Sample Paper 2018-19)
Answer:
A-Haploid
B-Diploid

Question 21.
Write one advantage and one disadvantage of cleistogamy to flowering plants? (CBSE Delhi 2018C)
Answer:
Advantage:
It maintains pure lines.

Disadvantage:
Only parental characters are preserved.

Question 22.
Why does the zygote begin to divide only after the division of the primary endosperm cell?
Answer:
Division and storage of food in primary endosperm cell forms endosperm which is pre-requirement for developing embryo, which is formed due to division of the zygote.

Sexual Reproduction in Flowering Plants Important Extra Questions Short Answer Type

Question 1.
What is inflorescence?
Answer:
The arrangement and distribution of flowers on a peduncle are called an inflorescence. The axis of the inflorescence is termed peduncle. The flattened peduncle is called the receptacle.

Question 2.
Differentiate between flower and inflorescence?
Answer:
Differences between flower and inflorescence:

Flowers	Inflorescence
1. It is a modified shoot.	1. It is an arrangement of flowers on the floral axis.
2. The stalk of flowers is called Pedicet.	2. The stalk of an inflorescence is called a peduncle.

Question 3.
List the functions of a flower?
Answer:
Functions of a flower:

1. Production of pollen and ovules.
2. Aids in pollination.
3. Fertilisation.
4. Development of seed and fruit.
5. Helps in the dispersal of seeds and fruits.

Question 4.
Name the various methods by which anther dehisces?
Answer:

1. By Longitudinal intros.
2. By Longitudinal dextrose.
3. By Apical pores.
4. Transverse dehiscence.

Question 5.
Geitonogamy flowering plants are genetically autogamous but functionally cross-pollinated? Justify? (CBSE 2013)
Answer:

1. Geitonogamy. It is a transfer of pollen grains from the anther to the stigma of another flower of the same plant.
2. Geitonogamy is functionally cross-pollination because it involves a pollinating agent, however genetically it is similar to autogamy since the pollen grains come from the same plant.

Question 6.
List the advantages of self-pollination?
Answer:
Advantages of self-pollination:

1. Parental characters can be preserved.
2. Self-pollination helps in maintaining pure lines.
3. No extra energy required, thus it is an economical process.
4. Even if smaller quantities of pollen grains are produced, there is a high chance of pollination.
5. Self-pollination avoids wastage of pollen grains.

Question 7.
What are the disadvantages of self¬pollination?
Answer:
Disadvantages of self-pollination:

1. There is a gradual decrease in the vigour of the plants produced through self-pollination.
2. The yield is decreased.
3. The size and number of seeds also go on decreasing generation after generation.
4. The plants become susceptible to diseases.

Question 8.
Give the characters of wind-pollinated flowers?
Answer:
Characters of wind-pollinated flowers:

1. The size of the flower is very small.
2. Bright coloured corolla, nectar glands and fragrance are absent.
3. Pollen grains are produced in large quantities.
4. Versatile fixation of anthers aids in shaking off pollen grains in the air.
5. Pollen grains are dry, smooth and very light, e.g. coconut palm, date palm, Cannabis (Bhang), maize and grasses.

Question 9.
Define ornithophily, chiropterophily and malacophilous?
Answer:

• Ornithophily: Pollination carried out by small birds is called ornithophily, e.g. Australian plants.
• Chiropterophily: It is pollination by bats, e.g. Sausage tree.
• Malacophily: Snails also bring pollination; it is termed malacophilous.

Question 10.
Give an account of the significance of double fertilisation? (CBSE 2010)
Answer:
Significance of double fertilisation:

1. After double fertilisation, the development of the endosperm starts when it is required by developing embryo.
2. It ensures that nutritive tissue is formed.
3. It is an advanced character over gymnosperms where endosperm develops before fertilisation. If fertilisation fails, the energy spent on endosperm development gets wasted; while in angiosperms it develops after double fertilisation.
4. Double fertilisation provides the characteristics of male plants as well as the nutritive tissue.

Question 11.
Describe the structure of the fruit?
Answer:
Structure of Fruit: True fruit is enclosed by a wall called the pericarp. When well developed and fleshy, it is differentiated (in most fruits) into three distinct parts-an outer epicarps, middle mesocarp and inner endocarp. In the ripe mango the outer, thin and leathery part (peel), which is usually discarded, is the epicarp.

The sweet, fleshy part that is edible is the mesocarp, and the innermost hard and woody part that encloses the seed is the endocarp. The nature of these three parts, however, varies in different fruits.

In dry fruits, the pericarp is dry, usually papery or woody, and is not distinguishable into the three parts.

Question 12.
(i) Suppose the haploid number of chromosomes in a flowering plant is 12. What will be the ploidy in the cells of integuments, nucellus, antipodals, endosperm and embryo of that plant?
Answer:

Name of the part	No. of Chromosomes
(a) Integument (2n)	12 × 2 = 24
(b) NuceLtus (2n)	12 × 2 = 24
(c) Antipodats (in)	12 × 1 = 12
(d) Endosperm (3n)	12 × 3 = 36
(e) Embryo (2n)	12 × 2 = 24

(ii) How many haploid cells are present in a mature female gametophyte of a flowering plant? Name them? (CBSE 2010)
Answer:
(a) 6 haploid cells
(b) 3 antipodals, 1 egg cell and 2 synergids.

Question 13.
What do you mean by monosporic development of female gametophyte?
Answer:
In monosporic development as in (Polygonum) the development of embryo sac, only one megaspore situated towards chalazal end remains functional. The remaining three megaspores gradually degenerate and finally disappear. The functional haploid megaspore enlarges in size and, by means of three successive mitotic divisions, gives rise to an eight- nucleate embryo sac.

Question 14.
(i) How are parthenocarpic fruit produced by some plants and apomictic seeds by some? Explain.
Answer:
Parthenocarpy is the production and development of seedless fruits without pollination and fertilisation. Parthenocarpic fruits are normal. Example: Banana, Pineapple, Guava, Grapes, etc.

Apomixis is the mode of reproduction which does not involve the formation of zygote through gametic fusion. Example: Some species of grass.

(ii) When do farmers prefer using apomictic seeds? (CBSE Outside Delhi 2016)
Answer:
Farmers prefer apomictic seeds because they are free from infection and avoid using hybrid seeds which are costly.

Question 15.
Write any two ways by which apomictic seeds may be developed in angiosperms? (CBSE Delhi 2019 C) Answer:
Parthenocarpy. In certain plants, the fruits are formed without the act of fertilisation. Such fruits are called parthenocarpic fruits and the phenomenon is known as parthenocarpy. Parthenocarpic fruits are either seedless or contain empty or non-viable seeds.

In these fruits, the stimulus (seed factor) for fruit growth is provided by the tissue of the ovary wall itself. Seedless varieties of grapes and oranges contain those of the seeded varieties. Most commonly cultivated varieties of banana and pineapple are parthenocarpic. Polyembryony: Formation of more than one embryo in the seed. Onions, groundnuts, mangoes lemons and oranges are some of the examples. Polyembryony is very common among conifers.

Question 16.
You are conducting artificial hybridisation on papaya and potato. Which one of them would require the step of emasculation and why? However, for both, you will use the process of bagging. Justify giving one reason? (CBSE Delhi 2019)
Answer:

1. Potato: Potato plant has a bisexual flower, which means it has both male and female reproductive parts in the same flower. And the plant is Monoecious. Hence it needs emasculation to prevent autogamy.
2. Papaya: In case of papaya plant, male and female flowers are present on separate plants, that is each plant is either male or female (dioecious). This condition prevents both autogamy and geitonogamy.

So for artificial hybridisation, both will require bagging to prevent contamination of stigma.

Question 17.
Normally one embryo develops in one seed but when an orange seed is squeezed many embryos of different shapes and sizes are seen. Mention how it has happened? (CBSE 2011)
Answer:
In many citrus varieties, some of the nucellar cells surrounding the embryo sac start dividing, protrude into embryo sac and develop into embryos. In such species, each ovule contains many embryos. The occurrence of more than one embryo in a seed is referred to as polyembryony.

Question 18.
A pollen grain in angiosperm at the time of dehiscence from an anther could be 2-celled or 3-celled. Explain. How are the cells placed within the pollen grain when shed at a 2-celled stage? (CBSE 2017)
Answer:
In the majority of angiosperms, pollens are released in a 2-celled stage. However, in other species, the generative cell divides into two male gametes and forms a 3-celled stage. When the pollen grain is shed at the 2-celled stage, it has two unequal cells, a bigger vegetative cell and a smaller generative cell.

Question 19.
Do you think apomixis can be compared with asexual reproduction? Support your answer, giving one reason. How is apomixis beneficial to farmers? Explain. (CBSE Delhi 2018C)
Answer:
A few flowering plants such as some species of Asteraceae and grasses have evolved a special mechanism to produce seeds without fertilisation. This is called apomixis. So apomixis is a form of asexual reproduction.

Production of hybrid seeds is costly; if hybrids with desirable characteristics can be made into apomicts, there is no segregation of characters in the hybrid progeny. The farmer can continue using hybrid seeds year after year and need not to buy new seeds.

Sexual Reproduction in Flowering Plants Important Extra Questions Long Answer Type

Question 1.
Give an account of a structure of typical anther?
Answer:
Structure of anther. A typical angiosperm anther is bilobed with each lobe having two cells or theca, i.e. they are dithecous. Often a longitudinal groove runs lengthwise separating the theca. The bilobed nature of an anther is very distinct in the transverse section of the anther. The anther is a four-sided (tetragonal) structure consisting of four microsporangia located at the corners, two in each lobe.

The microsporangia develop further and become pollen sacs. They extend longitudinally all through the length of an anther and are packed with pollen grains.

Question 2.
Write about the structure of microsporangium? (CBSE 2014)
Answer:
A microsporangium is more often circular in outline and is surrounded by a four-layered wall:

1. The outermost layer is the single layer of the epidermis.
2. The second layer is endothecium, where cells develop thickenings.
3. The middle layer is of 2-4 cells.
4. Tapetum, the innermost layer, is of large diploid/polyploid and binucleate or multinucleate cells.
5. There are four pollen sacs.
6. Each pollen sac has sporogenous tissue.

Question 3.
Describe the development of microspore in angiosperms?
Answer:
Microsporogenesis and formation of pollen grains:

1. Every cell of the sporogenous tissue is a potential pollen mother cell (PMC) and can give rise to microspore tetrad/ pollen grains.
2. But some of them forego this potential and differentiate into the pollen mother cells of microspore mother cells.
3. Each microspore mother cell undergoes meiosis to form a cluster of four haploid cells, called microspore tetrad.
   
4. As the anther matures, the microspores dissociate from the tetrad and develop into pollen grains.
5. The tetrad may be tetrahedral, isobilateral, T-shaped, L-shaped and linear.
6. The nucleus of the microspore undergoes mitosis to form large vegetative cell and a small spindle¬shaped generative cell that floats in the cytoplasm of the vegetative cell.

Question 4.
What is pollination? Name different types of pollination?
Answer:
Pollination: It is the transfer of pollen grains from the anther to stigma.

Question 5.
With a neat diagram, explain the 7-celled, 8-nucleate mature female gametophyte? (CBSE Delhi 2014, Outside Delhi 2019)
Answer:
Structure of mature female gametophyte. The female gametophyte is formed from the contents of megaspore. However, it always remains embedded within the membrane of the megaspore. The mature female gametophyte is 7-celled (an egg, two synergids, three antipodals and a central cell).

Out of the seven cells of mature female gametophyte, the egg cell fuses with male gamete to form a zygote, one synergid degenerates and the other synergid directs the pollen tube entry. The central cell fuses with the male gamete to form triploid primary endosperm nucleus and the three antipodals degenerate before or after fertilisation.

They sometimes act as antipodal haustoria:

Question 6.
Tabulate the differences between self-pollination and cross-pollination?
Answer:
Differences between self-pollination and cross-pollination:

Self-pollination	Cross-pollination
1. It is the transference of pollen grains from the anther to the stigma of the same flower.	1. It is the transference of pollen grains from the anther to the stigma of another flower of another plant.
2. Self-pollination always occurs through touch or wind.	2. Cross-pollination always occurs through an external agent.
3. Both anthers and stigmas mature simultaneously.	3. The anthers and stigmas mature at different times.
4. It can occur in closed flowers.	4. It occurs only when the flowers are open.
5. It gives rise to pure lines.	5. It gives rise to offspring having variations.

Question 7.
Briefly explain contrivances for self-pollination?
Answer:

Question 8.
What is bagging technique? How is it useful in plant breeding programmes?
Answer:
Bagging technique: It is a technique used during artificial hybridisation of plant breeding to ensure cross-pollination.

For this removal of anthers from the flower bud before the anther dehisces using a pair of forceps is necessary. This step is referred to as emasculation. Emasculated flowers have to be covered with a bag of suitable size, generally made up of butter paper, to prevent contamination of its stigma with unwanted pollen.

This process is called bagging. When the stigma of bagged flower attains receptivity, mature pollen grains collected from anthers of the male parent are dusted on the stigma, and the flowers are rebagged, and the fruits are allowed to develop.

If the female parent produces unisexual flowers, there is no need for emasculation. The female flower buds are bagged before the flowers open. When the stigma becomes receptive, pollination is carried out using the desired pollen and the flower rebagged.

Advantages of bagging technique:

1. It is necessary for cross-breeding for the crop improvement programme.
2. Commercially superior varieties can be obtained.

Question 9.
What are zoophily, zoophilous flowers and entomophilous flowers? List the characters of entomophilous flowers?
Answer:

• Zoophily: Pollination by animals is called Zoophily.
• Zoophilous flowers: The flowers which get pollinated with the aid of animals are called zoophilous flowers.
• Entomophilous flowers: Insect pollinated flowers are called entomophilous flowers.

Characters of Entomophilous flowers:

• The flowers are of large size.
• Corolla of flowers is brightly coloured.
• Some flowers are very fragrant.
• They bear nectar-secreting glands.
• The pollen grains are heavy with the rough and spiny surface.
• The stigmatic surface is sticky.

Question 10.
What are the advantages of cross-pollination?
Answer:
Advantages of cross-pollination:

1. It increases variability and certain new and useful characters appear in the offsprings.
2. Sometimes harmful characters are eliminated.
3. It leads to the production of new varieties.
4. Several disease-resistant varieties of important crop plants have been produced as a result of cross-pollination.
5. It increases the power of adaptation among the offsprings.
6. The number of seed production can be increased among useful cereal crops.

Question 11.
Differentiate between anemophilous and entomophilous flower? (CBSE Delhi 2008 (S))
Answer:
Differences between anemophilous and entomophilous flowers:

Anemophilous flower	Entomophilous flower
1. The flowers are small.	1. The flowers are either Large or if small the are grouped to form a mass.
2. Flowers are neither brightly coloured nor emit any odour.	2. The flowers are brightLy coLoured and emit odour.
3. The flowers are devoid of any nectar and edible pollen.	3. The flowers usually possess nectar or edible pollen.

Question 12.
How does the floral pattern of Mediterranean orchid Ophrys guarantee cross-pollination? (CBSE 2010, 2019)
Answer:
In many species of Mediterranean orchid Ophrys, the shape, colour marking and odour of flower are like the female moth Colpa.

The Ophrys employs sexual deceit to get pollination done by the Colpa. The male moth matures earlier than the female. It mistakes the Ophrys flower for female and tries to copulate. Thus it pollinates the flower.

Question 13.
Explain the events in the embryo sac during the process of fertilisation?
Answer:
Fertilisation. The fusion of male and female gametes is called fertilisation. The process was first discovered by Strasburger (1884).

Pollen tube enters through the micropyle and releases male gametes. This is called Porogamy. If pollen tube enters through chalaza, it is called chalazogamy and if pollen tube enters through integuments, it is called misogamy. One male gamete (1n) fuses with egg or oosphere to form oospore (2n) and second male gamete fuses with secondary nucleus (2n) to form the primary endosperm nucleus (3n).

In angiosperms where both male gametes are functional and bring about fertilisation of oosphere and secondary nucleus to form oospore and primary endosperm nucleus, is called double fertilisation.

Question 14.
What do you understand by double fertilisation? (CBSE Sample Paper) (CBSE Delhi (C) 2008)
Or
Where does triple fusion take place in a flowering plant? (CBSE 2010)
Answer:
In angiosperms both the male gametes are functional. Double fertilisation is a process in which the egg nucleus and secondary nucleus are fertilized at one time by the male gametic nuclei. The fusion of one male gamete nucleus (1n) with egg or oosphere (1n) is called syngamy and results in the formation of oospore (2n).

The second male gamete fuses with the secondary nucleus; it is called triple fusion which results in the formation of the primary endosperm nucleus (3n). Thus it takes place in the embryo sac. It was first discovered by Nawaschin (1898).

Question 15.
What is the fate of floral parts after fertilisation?
Answer:
After fertilisation, the transformation of parts of the flower is as follows:

Before fertilization	After fertilization
1. Calyx, Corolla, Androecium, Style, Stigma	Wither off
2. Ovary	Fruit
3. Ovary wall	Pericarp
4. Ovule	Seed
5. Integuments	Seed coats
6. Outer integument	Testa
7. Inner integument	Teg men
8. Micropyle	Macrophyte
9. Funicte	Stalk of seed
10. Nucellus (persistent)	Pensperm
11. Egg cell	Zygote (oospore)
12. Synergids	Disintegrate and disappear

Question 16.
Write an account of various types of fruits?
Answer:
Types of fruits:

• Simple fruit: Fruits develop from a single ovary.
• Aggregate fruit: Develops from the polycarpellary, apocarpous ovary. Composite fruit. Which develops from the inflorescence.
• Dry fruit: When mesocarp, epicarp and endocarp all are hard.
• Succulent fruit: When mesocarp is pulpy.

Question 17.
Mention two strategies evolved by flowers to prevent self-pollination? (CBSE 2014)
Answer:
Contrivances favouring cross-pollination In many plants there are devices which completely or partially prevent self-pollination and encourage cross¬pollination.

1. Unisexuality: The flowers are unisexual, i. e. stamens and carpels occur in different flowers. They may be present on the same plant, e.g. in maize or on different plants, e.g. in Papaya. The first condition is called monoecious and second is called dioecious.
2. Dichogamy: When stamens and carpels of bisexual flowers mature at different times, it is called dichogamy. If stamens mature first it is called a protandrous condition, or if carpels mature first it is called protogynous condition.

Question 18.
Draw a monocot endospermic seed? (CBSE 2012, 2019)
Answer:
Seeds of angiosperm:

Seeds of angiosperm.

Question 19.
Give a brief account of post-pollination events? (CBSE Delhi 2016)
Answer:
Post-pollination events:

1. The fusion of male and female gametes is called fertilisation. The process was first discovered by Strasburger (1884).
2. Pollen tube enters through the micropyle and releases male gametes. This is called Porogamy. If pollen tube enters through chalaza, it is called chalazogamy and if pollen tube enters through integuments, it is called misogamy.
3. One male gamete fuses with egg or oosphere to form oospore (2n) and second male gamete fuses with secondary nucleus (2n) to form the primary endosperm nucleus (3n).
4. In angiosperms where both male gametes are functional and bring about fertilisation of oosphere and secondary nucleus to form oospore and primary endosperm nucleus, is called double fertilisation.
5. Development of endosperm from the primary endosperm nucleus.
6. Development of embryo from a zygote,
7. Development of seed from the ovule.

Question 20.
(i) Can a plant flowering in Mumbai be pollinated by pollen grains of the same species growing in New Delhi? Provide explanations for your answer.
Answer:
Yes, it is possible by artificial hybridisation in which pollen grains of one flower is introduced artificially on the stigma of another flower. But there should not be self-incompatibility.

However, it is important to make sure that only the desired pollen grains are used for pollination and the stigma is protected from contamination (from unwanted pollen). This is achieved by emasculation and bagging techniques.

(ii) Draw the diagram of a pistil where pollination has successfully occurred. Label the parts involved in reaching the male gametes to its desired destination. (CBSE 2017)
Answer:

Question 21.
Differentiate between parthenocarpy and parthenogenesis. Give one example of each? (CBSE2018)
Answer:
Parthenocarpy is the process which produces fruits from unfertilised ovules in plants. Unfertilised ovules develop into fruits prior to fertilisation. Such fruits do not contain seeds.

However, parthenogenesis can be described as a process in which unfertilised ovum develops into an individual (virgin birth) without fertilisation. Therefore, it can be considered a method of asexual reproduction.

Such a type of reproduction is commonly shown by some invertebrates and lower plants, e.%. rotters, honeybees and some lizards and birds (turkey), etc.

Another key difference between parthenogenesis and parthenocarpy is parthenogenesis is shown by animals and plants while parthenocarpy is shown by plants only.

Question 22.
The embryo sac in female gametophyte is seven celled and eight nucleated structure. Justify the statement with the help of a labelled diagram? (CBSE Sample Paper 2018-19)
Answer:
A typical embryo sac has three cells that are grouped together at the micropylar end and constitute the egg apparatus. The egg apparatus, in turn, consists of two synergids and one egg cell.

Three cells are at the chalazal end and are cast the antipodals. The Large central cell has two polar nuclei.

Thus, a typical angiosperm embryo sac at maturity is 7-celled and 8-nucLeated.

Question 23.
List the changes that occur when an ovule matures into a seed? (CBSE Sample Paper 2018-19)
Answer:

1. Integuments of ovules harden and become tough protective seed coats.
2. The micropyle remains as a small pore in the seed coat.
3. As the seed matures, its water content is reduced.
4. Seeds become relatively dry. It has 10-15 percent moisture by mass.
5. The general metabolic activity of the embryo slows down.
6. The embryo may enter a state of inactivity called dormancy.

Question 24.
What are the various adaptations or contrivances met within angiosperms flowers which favour cross-pollination?
Answer:
Contrivances favouring cross-pollination: In many plants, there are devices which completely or partially prevent self-pollination and encourage cross-pollination.
1. Unisexuality: The flowers are unisexual, i.e. stamens and carpels occur in different flowers. They may be present on the same plant, e.g. in Three cells are at the chalazal end and are called the antipodals. The large central cell has two polar nuclei.

Thus, a typical angiosperm embryo sac at maturity is 7-celled and 8-nucleated.

Structure of typical embryo sac.

maize or on different plants e.g. in Papaya. The first condition is called monoecious and second is called dioecious. In monoecious plants, both self-and cross-pollination can occur but mostly there is cross-pollination as sex organs mature at different times. In dioecious only cross-pollination occurs.

2. Dichogamy: When stamens and carpels of bisexual flowers mature at different times it is called dichogamy.

If stamens mature first, it is called a protandrous condition, or if carpels mature first, it is called protogynous condition. Dichogamy prevents self-pollination and ensures cross-pollination.

3. Self-sterility: In orchids, pollen grains of one flower does not germinate on the stigma of the same flower. This is called self-sterility but pollen grain germinates on the stigma of some other plant and thus ensures cross pollination.

4. Heterostyly: In primrose, there are different lengths of styles which ensure cross-pollination.

5. Herkogamy (Herko-barrier): In bisexual flowers, e.g. in Salvia and pea, peculiarities of petals ensure insect pollination, thus aids in cross-pollination.

Question 25.
With a neat labelled diagram, describe the parts of a typical angiosperm ovule? (CBSE Delhi 2014)
Answer:
Structure of ovule. Each ovule consists of nucellus surrounded by two integuments and a stalk or funiculus.

1. Funiculus is a stalk-like structure by which ovule is attached to the placenta.
   
   v.s. of the mature ovule to show various parts.
2. Hilum: It is the point of attachment of the body of the ovule with the funiculus.
3. Raphe: It is the longitudinal ridge formed by the lengthwise fusion of funiculus with the body of ovule in a typical anatropous ovule.
4. Nucellus: It is a mass of diploid cell called megasporangium. It provides nourishment in the development of embryo sac.
5. Embryo sac: It is the female gametophyte which contains the egg apparatus.
6. Integuments from seed coats, i.e. testa and tegmen.
7. Micropyle: It is a small opening which is left by the integument in the ovule for the passage of pollen tube into the ovule.
8. Chalaza: The basal region of the ovule where the funiculus is attached is termed chalaza.

Question 26.
Describe the structure of typical embryo sac and the functions performed by its various constituents?
Or
Draw a schematic labelled diagram of fertilized embryo sac of angiosperm? (CBSE 2008, 2012, 2013)
Answer:
In the mature ovule, within the nucellus towards the micropylar end is a large cell called embryo sac. It is also called a female gametophyte. It contains cytoplasm, two free nuclei and six small cells. Two free nuclei fuse to form a secondary nucleus.

Out of these, three cells constitute egg apparatus (two synergids and one oosphere or egg cell). The other three cells lie at the chalazal end of embryo sac and are called antipodal cells. They are small and enclosed in thin cell walls.

In egg apparatus, egg fuses with male gamete to form zygote or oospore which later gives rise to the embryo. Synergids help in fertilisation. Secondary nucleus fuses with the second male gamete to form primary endosperm nucleus which later on forms endosperm.

The three antipodal cells degenerate:
A typical embryo sac has three cells that are grouped together at the micropylar end and constitute the egg apparatus. The egg apparatus, in turn, consists of two synergids and one egg cell.

Three ceLLs are at the chaLazaL end and are cast the antipodals. The Large centraL ceLL has two poLar nucLei.

Thus, a typical angiosperm embryo sac at maturity is 7-celLed and 8-nucLeated.

Question 27.
Describe the structure of typical microspore (pollen grain)?
Or
Name the organic material of exine and intine of an angiospermous pollen grain. Mention their role. (CBSE Delhi 2014) Answer:
Structure of pollen grains:

1. Pollen grains are normally spherical in outline.
2. Each pollen grain has a prominent two-layered wall.
3. The outer layer is called exine and the inner layer is called intine.
4. The exine is hard and made of sporopollenin. It shows a variety of architecture as per the characteristic of each species.
   
5. Intine is thin and it is made of cellulose and pectin.
6. At certain places, exine is either absent or very thin and such places are called germ pores. In monocots, there are germinal furrows.
7. A mature pollen grain has two cells-a vegetative cells and a generative cell.
8. The vegetative cell is larger, has abundant reserve food and a large irregular-shaped nucleus.
9. The generative cell is small, spindle¬shaped and floats in the cytoplasm of the vegetative cell.

Question 28.
Draw a well-labelled diagram of T.S. of the anther? (CBSE Sample paper 2009)
Or
Draw a labelled schematic diagram of the transverse section of a mature anther of an angiosperm plant. (CBSE Delhi 2013)

Answer:
T. S. of anther

(A) Transverse section of a tetra eusporangiate anther to show its various tissue;
(B) Enlarged view of one microsporangium showing wall layers.

Question 29.
Explain the development of the female gametophyte. Illustrate the answer with suitable diagrams? (CBSE Delhi 2019, Outside Delhi 2019)
Answer:
Development of female gametophyte:

1. The functional megaspore is the first cell of the female gametophyte of angiosperms.
2. It enlarges to form the female gametophyte, also called embryo sac.
3. Its nucleus undergoes a mitotic division and the two nuclei move to the opposite poles, forming the 2-nucleate embryo sac.
4. Two successive mitotic divisions in each of these two nuclei result in the formation of an 8-nucleate embryo sac.
   
   Fig. Development of embryo sac.
5. Cell wall formation starts at the eight-nucleate stage, resulting in the formation of a typical female gametophyte.
6. Three cells are grouped together at the micropylar end to form the egg apparatus, consisting of two synergids and a female gamete/egg cell.
7. Three cells are grouped together at the chalazal end. They are called antipodal cells.
8. The remaining two nuclei are called polar nuclei. They move to the centre of the embryo sac (now called a central cell) and fuse to form a diploid secondary nucleus.
9. Thus, a typical angiosperm embryo sac is 8-nucleate and 7-celled.

Question 30.
Show the germination of pollen grain with diagrams only? (CBSE 2011, 2019 C)
Answer:
Germination of Pollen Grain:

Germination of pollen grain and formation of male gametophyte in an angiosperm.

Question 31.
What do you mean by the development of the embryo? Support the answer with a diagram? (CBSE Delhi 2014)
Answer:
Development of embryo.
1. The zygote or oospore divides by a transverse wall into an upper suspensor cell and lowers embryonal cell.

2. The suspensor cell which lies towards the micropylar end divides by transverse divisions to constitute 7-10 cells called suspensor.

3. The upper cell of the suspensor filament towards the micropylar end is called a haustorial cell, whereas the cell lying above the embryo cell is called hypophysis.

4. The haustorial cell enlarges in size and attaches the suspensor to the tip of embryo sac.

5. The embryonal cell divides by second longitudinal division at a right angle to the first and then by transverse division to form an octant or eight- celled embryo.

6. Out of these eight cells, the lower four cells of octant away from the suspensor give rise to the plumule and the two cotyledons, while the above four cells of octant near the suspensor from the hypocotyl and stele of the radicle.

7. Then this octant divides by a periclinal division to form outer single-layered dermatogen from which arises the epidermis layer. The inner cells further divide to form periblem below the dermatogen and the central plerome.

8. The periblem forms the cortex while the plerome gives stele of the embryo.

9. The lowermost cell of suspensor, which is lying just above the octant cells is known as hypophysis. The hypophysis divides to give rise to the dermatogen and periblem of the radicle.

10. A fully developed embryo of dicotyledons has an embryonal axis differentiated into plumule, two cotyledons and radicle.

11. In the beginning, the embryo is globular. When two cotyledons differentiate from the sides with faint plumule in the centre, the embryo becomes heart¬shaped. Then the embryo undergoes rest and ovule is transformed into the seed.

Monocot embryo: Unlike the dicots where the embryonal mass is formed of eight cells, the anterior cells forming the plumule and the cotyledons, and the posterior forming hypocotyl, the development is much variable in monocots, i.e. grass family. In some cases, suspensor does not develop at all. Only one cotyledon appears in monocots as a terminal structure. The plumule always appears laterally from it.

Question 32.
Draw the stages of development of the embryo in a dicot angiosperm?
Answer:
Stages of embryo development in a dicot angiosperm:

Stages of embryo development in a dicot angiosperm.

Question 33.
Explain the role of tapetum in the pollen grain wall formation?
Answer:
Role of tapetum in pollen grain wall formation. During microsporogenesis, the cells of tapetum provide various enzymes, hormones, amino acids and other nutritive materials to the dividing microsporocytes.

The main functions of tapetum are:

1. Transportation of nutrients into anther locule at the time of meiosis in spore mother cells.
2. Secretion of enzymes and hormones.
3. Production of Ubisch bodies which are coated with sporopollenin to cause thickening of the exine.
4. Secretion of any oily material (Pollenkitt) outside of mature pollen.
5. Secretion of special proteins for pollen to recognise compatibility.

Question 34.
Describe in brief the various special modes of reproduction? Mention their economic significance?
Answer:
Special modes of reproduction:
1. Apomixis (Agamospermy): It is a modified form of reproduction in which seeds are formed without fusion of gametes. It includes the process whereby a diploid cell of nucellus develops into an embryo, giving a diploid seed with a genetic constitution identical to the parent. The organism that reproduces by apomixis is called apomict.

2. Parthenocarpy: In certain plants, the fruits are formed without the act of fertilisation. Such fruits are called parthenocarpic fruits and the phenomenon is known as parthenocarpy. Parthenocarpic fruits are either seedless or contain empty or non-viable seeds. In these fruits, the stimulus (“seed factor”) for fruit growth is provided by the tissue of the ovary wall itself. Seedless varieties of grapes and oranges contain those of the seeded varieties. Most commonly cultivated varieties of banana and pineapple are parthenocarpic.

3. Polyembryony: It is the formation of more than one embryo in the seed. Onion, groundnut, mango, lemon and oranges are some of the examples. Polyembryony is very common among conifers.

4. Sporophytic budding: It may occur in the nucellus and integuments, resulting in the development of an embryo. Examples: Orange, mango, onion, etc.

5. Micropropagation: In this method, tissue and organ culture is utilised. Tissue or organs grow on suitable medium containing hormones. Tissue proliferates to form a callus. From this callus, arise new plantlets. Each plantlet, when transferred to pot or soil, produces a new plant. Thus by this method, an indefinite number of plants can be raised from a small mass of partial tissue.

6. Plant tissue culture. It also helps in propagating plants to a great extent.

Question 35.
Fertilisation is essential for the production of seed, but in some angiosperms, seeds develop without fertilisation?
(i) Give an example of an angiosperm that produces seeds without fertilisation. Name the process.
Answer:
(a) Species of Asteraceae and grass.
(b) Process of formation of seeds without fertilization is called apomixis.

(if) Explain the two ways by which seeds develop without fertilisation. (CBSE 2009)
Answer:
Apomixis is a form of asexual reproduction that mimics sexual reproduction:
(a) The diploid egg cell is formed without reduction division and develop into an embryo without fertilisation.
(b) In some varieties of citrus and mango, some of the nucellar cells surrounding the embryo sac start dividing, produce embryo sac and develop into embryos. In such species, each ovule contains many embryones. Such a process is called polyembryony.

Question 36.
Write a note on the development of endosperm. Mention the types with examples?
Answer:
Development of endosperm: Endosperm develops after double fertilisation in angiosperms. It is triploid and develops from the primary endosperm nucleus.

In angiosperms three types of endosperm development are observed:
1. Nuclear endosperm. In nuclear endosperm development, the nucleus divides by free nuclear division, there is the appearance of the central vacuole, all the nuclei are pushed towards periphery then starts cytokinesis and results in the formation of cells but in coconut, vacuole persists which is filled with fluid.

2. Cellular endosperm. In cellular endosperm, each and every division is followed by cytokinesis, so endosperm is cellular from the very beginning, e.g. Datura, Petunia.

3. Helobial endosperm. It is intermediate between cellular and nuclear endosperm. The first division is followed by cytokinesis to form two unequal cells, micropylar cell and chalazal cell. Further divisions in each cell are free nuclear divisions. This type of endosperm is found in order Helobiales.

Types of endosperm development.

Question 37.
What are the advantages of seeds to plants and mankind? (CBSE Delhi 2014)
Answer:
1. Advantages of seeds to plants:
(a) Seeds have better adaptive strategies for dispersal to new habitats for better survival.
(b) Seeds have reserve food materials to nourish the seedlings during seed germination.
(c) The hard seed coat provides protection to the young embryo.
(d) Since seeds are formed after sexual reproduction, they show genetic recombinations leading to variations.
(e) Since seed formation does not depend on water (for fertilisation), their formation is more certain and they are the units of multiplication and continuity of the species.

2. Advantages of seeds to mankind:
(a) Seeds are stored and used as food throughout the year.
(b) Seeds are also used to raise the crop in the favourable seasons depending on their viability.

Question 38.
(i) Draw a diagrammatic sketch of a transverse section of an anther of an angiosperm. Label its different walls and the tissue forming microspore mother cells?
Answer:
T. S. of anther

(A) Transverse section of a tetra eusporangiate anther to show its various tissue;
(B) Enlarged view of one microsporangium showing wall layers.

(ii) Describe the process of microsporogenesis up to the formation of a microspore?
Answer:
Microsporogenesis and formation of pollen grains:

1. Every cell of the sporogenous tissue is a potential pollen mother cell (PMC) and can give rise to microspore tetrad/ pollen grains.
2. But some of them forego this potential and differentiate into the pollen mother cells of microspore mother cells.
3. Each microspore mother cell undergoes meiosis to form a cluster of four haploid cells, called microspore tetrad.
   
4. As the anther matures, the microspores dissociate from the tetrad and develop into pollen grains.
5. The tetrad may be tetrahedral, isobilateral, T-shaped, L-shaped and linear.
6. The nucleus of the microspore undergoes mitosis to form large vegetative cell and a small spindle¬shaped generative cell that floats in the cytoplasm of the vegetative cell.

(iii) Write the function of ‘germ pore’ in a pollen grain of an angiosperm? (CBSE Delhi 2018C)
Answer:
Germ pores allow the germinating of pollen tube with contents of the male gametes and vegetative cell to come out of the pollen grains.

Question 39.
(i) When a seed of orange is squeezed, many embryos instead of one are observed. Explain how it is possible?
Answer:
When a seed of orange is squeezed, many embryos instead of one are observed. It is due to polyembryony. Polyembryony is the occurrence of more than one embryo in a seed.

The nucellar cells, synergid or integument cells develop into a number of embryos of different sizes in orange.
Sometimes the formation of more than one egg in an embryo sac can lead to polyembryony.

(ii) Are these embryos genetically similar or different? Comment.
Answer:
These embryos are genetically similar because in such embryos parental characters are maintained. In this process, there is no segregation of characters in the offspring.

Question 40.
(i) Describe any two devices in a flowering plant which prevent both autogamy and geitonogamy?
(ii) Explain the events up to double fertilisation after the pollen tube enters one of the synergids in an ovule of an angiosperm? (CBSE 2018)
Or
Explain the post-pollination events up to double fertilization that occurs in angiosperm. (CBSE 2019 (c))
Answer:
(i) Autogamy: It is the transfer of pollen grains from the anther to the stigma of the same flower.

Geitonogamy: It is the transfer of pollen grains from the anther to the stigma of another flower of the same plant.

Two devices that prevent both autogamy and geitonogamy are:
(a) Self-incompatibility: This is a genetic mechanism which prevents self pollen from fertilising the ovules by inhibiting pollen germination or growth of pollen tube in the pistil.
(b) Dioecious plants: Male and female flowers are present on different plants.

(ii) The events seen after the pollen tube enters one of the synergids in an ovule is as follows:
(a) After reaching the ovary, pollen tube enters the ovule through the micropyle and thus enters one of the synergids through filiform apparatus.

(b) After entering one of the synergids, the pollen tube releases the two male gametes into the cytoplasm of the synergid.

(c) One of the male gametes moves towards the egg cell and fuses with its nucleus and results in the formation of the zygote (diploid cell). This is called syngamy.

(d) The other male gamete moves towards the two polar nuclei present in the central cell and fuses to form triploid primary endosperm nucleus (PEN) i.e., there is a fusion of three haploid nuclei and hence termed as triple fusion.

(e) Two types of fusions-syngamy and triple fusion-take place in an embryo sac. Hence the phenomenon is termed double fertilisation.

(f) After fertilisation, the primary endosperm nucleus becomes the primary endosperm cell (PEC) and develops into endosperm while zygote develops into an embryo.

Fig. (A) EnLarged view of an egg apparatus showing entry of poLLen tube into a synergy, (B) Discharge of male gametes into a synergid and the movements of the sperms, one Into the egg and the other Into the centraL celL.

Very Important Figures

Here we are providing Class 12 Biology Important Extra Questions and Answers Chapter 7 Evolution. Important Questions for Class 12 Biology are the best resource for students which helps in Class 12 board exams.

Class 12 Biology Chapter 7 Important Extra Questions Evolution

Evolution Important Extra Questions Very Short Answer Type

Question 1.
When did life appear on earth?
Answer:
Life originated sometimes 3600 million years ago.

Question 2.
Arrange the following substances in a proper sequence with regard to the formation of chemical constituents at the time of origin of life: Sugar, methane, nucleic acid, and amino acid.
Answer:
Methane-sugar-amino acid-nucleic acid.

Question 3.
Mention the type of nutrition in the cells that originated first during the origin of life.
Answer:
Heterotrophic nutrition.

Question 4.
Which group of organisms were responsible for the appearance of free oxygen in the atmosphere of the primitive earth?
Answer:
Oxygenic photosynthetic bacteria resembling the present-day blue-green algae or cyanobacteria.

Question 5.
Give the three key factors of the modern concept of evolution.
Answer:
Genetic variations, natural selection, and isolation.

Question 6.
What is the ultimate source of organic variation?
Answer:
Genetic variations due to mutations, recombination, and polyploidy.

Question 7.
What is proved by the phenomenon of resistance to DDT in mosquitoes?
Answer:
Natural selection.

Question 8.
Attempt giving a clear definition of the term species.
Answer:
The members of a species that resemble structurally and functionally are able to interbreed freely and produce fertile offspring of their own kind and share a common gene pool.

Question 9.
What causes speciation according to Hugo de Vries? (CBSE Delhi 2008)
Answer:
Mutations.

Question 10.
How did Charles Darwin express ‘fitness’? (CBSE Delhi 2019)
Answer:
Charles Darwin expressed ‘fitness’ as reproductive fitness. The adaptive ability of an organism is inherited. The best-adapted species increase their population by reproduction.

Question 11.
Name the scientist who disproved spontaneous generation theory. (CBSE 2010)
Answer:
Louis Pasteur.

Question 12.
Mention the type of evolution that has brought the similarity as seen in potato tuber and sweet potato. (CBSE 2009)
Answer:
Convergent evolution.

Question 13.
Briefly explain the theory of biogenesis. (CBSE 2012)
Answer:
According to this theory, life originated from pre-existing life forms.

Question 14.
Write the probable difference in eating habits of Homo habilis and Homo erectus. (CBSE Outside Delhi 2016)
Answer:
Homo habilis was carnivorous. Homo erectus was omnivorous.

Question 15.
How do we compute the age of a living tree?
Answer:
By determining the number of annual rings in the lower part of its trunk, called dendrochronology.

Evolution Important Extra Questions Short Answer Type

Question 1.
What are we referring to when we say “simpler organisms” or “complex organisms”?
Answer:
By “simpler organisms”, we mean those organisms which are primitive with simple organization and simple metabolic pathways, structural and functional. “By complex organisms”, we mean those organisms which are more evolved, have a complex level of structural and functional organization and complex metabolic pathways.

Question 2.
Louis Pasteur’s experiments, if you recall, proved that life can arise from only pre-existing life. Can we correct this as life evolves from pre-existent life or otherwise we will never answer the question as to how the first forms of life arose? Comment.
Or
State the two principal outcomes of the experiments conducted by Louis Pasteur on the origin of life. (CBSE Delhi 2019)
Answer:

1. Dismissed theory of spontaneous generation of life.
2. Yes, we can correct this as life evolves from pre-existent life.

The first life that appeared on the earth was apparently the result of chemical evolution, i.e. the life originated from inorganic molecules that formed organic molecules, further forming complex compounds.

This finally resulted in simple cells and then simple organisms, where-in complexity developed with time. However, once life originated, abiogenesis could not follow, and hence, life evolved further only through biogenesis, i.e. pre-existent life gave rise to new life.

Question 3.
What is convergent evolution?
Answer:
Convergent evolution. When adaptation for survival in similar habitats is similar, then this form of evolution is called convergent evolution or parallel evolution. Examples: Some of the marsupials of Australia resemble placental mammals that live in similar habitats to other continents. Australia separated about 50 million years ago. Marsupials arrived here before the separation from Antarctica and evolved in isolation earlier than placental mammals.

Question 4.
What are analogous organs? Give examples. (CBSE 2016)
Answer:
Analogous organs: The organs which are similar in appearance and perform the same function but differ in their fundamental structure and origin are called analogous organs.

Examples:

1. Wings of birds and insects.
2. Leaves of a plant and cladodes of Ruscus are also analogous organs.

Question 5.
What are vestigial organs? Give examples.
Answer:
Vestigial organs are non-functional organs in an organism that are functional in related animals and were functional in the ancestors. There are 90 vestigial organs in the human body and mainly include coccyx (tail bone); nictitating membrane (3rd eyelid); caecum and vermiform appendix; canines; wisdom teeth; body hair; auricular muscles; mammary glands in male; etc. Vestigial organs are also present in some other animals, e.g. splint bones in the horse; hind-limbs and pelvic girdles in python; wings and feathers in flightless birds; etc.

Question 6.
Write the significance of vestigial organs.
Answer:
Significance of vestigial organs. Organic evolution states that these vestigial organs were functional in the ancestral forms but have become non-functional due to changes in their function and may finally disappear. So the presence of vestigial organs is convincing evidence of organic evolution and is supported by Lamarck’s theory of use and disuse of organs.

Question 7.
What are fossils?
Answer:
Fossils. The remnants or impressions of living organisms from the remote past may be regarded as fossils. Fossil formation involves the burial of dead organisms. Layer after layer of sediment is laid above the dead organisms. It is only on this account that the oldest fossils are found in the deepest layers of the earth’s surface, while the fossils of recent origin are found in the upper layers. Thus by examining the various layers of the earth from the deepest to the most superficial strata for the fossil record, the story of life in the correct historical sequence can be known.

Question 8.
Why is Archaeopteryx called a connecting link between reptiles and birds?
Or
What is the significance of Archaeopteryx in the study of organic evolution?
Answer:
Importance of Archaeopteryx as connecting link. The fossil forms representing the characters of the two distinct groups of living animals are known as missing links. The best example of connecting link is afforded by a fossil bird, Archaeopteryx. It was the size of a crow. Archaeopteryx is decidedly a bird as it has feathers and a beak. But like reptiles, it has a long tail, jaws full of teeth, claws on forefingers, and keelless sternum. Thus it represents a stage between reptiles and birds through Archaeopteryx-like intermediate form.

Question 9.
What is adaptive radiation? (CBSE Delhi 2016)
Or
Describe one example of adaptive radiations. (CBSE Delhi 2008 S, 2010, 2015, 2019 C, Outside Delhi 2014)
Or
How did Darwin explain the existence of different varieties of finches on the Galapagos Islands? (CBSE Outside Delhi 2009, Delhi 2010)
Answer:
Adaptive radiation: It is the process of divergent evolution in which members of the same ancestral species of a large taxonomic group are evolved along different lines in different habitats of the same geographical area.

Example: Darwin’s Finches are an example of adaptive radiation.

There were many varieties of small blackbirds in the Galapagos Islands. Darwin reasoned that after originating from a common seed-eating stock, the finches must have radiated to different geographical locations in the same island and undergone adaptive changes, especially in the type of beak. Living in isolation for long, the new kinds of finches emerged that could survive and function in the new habitats.

Question 10.
List the main points of Lamarck’s theory.
Answer:
Lamarck’s theory of evolution:

1. Effect of environment.
2. Effect of use and disuse of organs.
3. The inheritance of acquired characters.
4. The origin of new species.

Question 11.
Give the main points of Darwin’s Theory of Evolution. (CBSE Outside Delhi 2019)
Answer:
Darwin’s Theory of Evolution may be summed up as follows:

1. Rapid multiplication/overproduction
2. Struggle for existence.
3. Variations.
4. Natural selection or survival of the fittest.
5. Inheritance of useful variations.
6. Origin of new species.

Alfred Wallace also arrived at the same conclusion as that of Charles Darwin.

Question 12.
Name the following:
(i) Who conceived the idea of the chemosynthetic hypothesis of the origin of life on earth?
Answer:
Oparin and Haldane

(ii) Who proved that spontaneous generation does not occur?
Answer:
Francesco Redi, Spallanzani, and Louis Pasteur

(iii) Who experimentally proved that life develops from pre-existing life only?
Answer:
Pasteur

(iv) Who gave the theory of organic evolution? (CBSE 2010)
Answer:
Charles Darwin.

Question 13.
Describe De Vries Mutation theory. (CBSE Delhi 2011)
Answer:
De Vries Mutation Theory: Hugo de Vries (1848-1935) was a Dutch Botanist. He performed experiments on the Evening Primrose (Oenothera Lamarckian). According to this theory, new species arise suddenly showing abrupt deviations in characters from the normal forms. These sudden deviations are because of mutation. Thus evolution is not a slow and gradual process but a sudden discontinuous and jerky process.

Question 14.
State a reason for the increased population of dark-colored moths coinciding with the loss of lichens (on tree barks/during industrialization period in England). (CBSE Delhi 2015)
Answer:
Soot evolved from coal-based industries deposited on tree bark of oak plants and darkened it, which is called industrial melanism. Dark-colored moth (Bistort Carbonaria) had more chances of survival so increased in number. Before industrialization, white-colored thick lichens grew on tree barks. In that background, white-winged moths survived but dark moths were picked out by predators.

But post-industrialization, lichens disappeared and tree trunks became dark due to the deposition of soot evolved from coal-based industries. Now white moths became easy prey compared to dark ones. Thus dark moths survived and increased their population.

Question 15.
Select the homologous structures from the combinations given below:
1. Fore-limbs of whale and bats
2. A tuber of potato and sweet potato
3. Eyes of Octopus and Mammals
4. Thorn of Bougainvillea and Tendril of Cucurbita. (CBSE Outside Delhi 2015)
Answer:

1. Because both of them share similarities in the pattern of bones of forelimbs, though they perform different functions like forelimb of whale helps in swimming, while that in bats it helps in flying.
2. Because both are modified stem branches (axillary buds) but are differently modified to perform different functions, e.g. thorns for protection from grazing animals and tendrils for climbing.

Question 16.
According to Hardy-Weinberg’s principle, the allele frequency of a population remains constant. How do you interpret the change of frequency of alleles in a population? (CBSE 2009)
Answer:
Disturbances in genetic equilibrium or Hardy-Weinberg equilibrium lead to a change of frequency of alleles in a population which results in evolution.

Question 17.
With the help of two suitable examples, explain the effect of anthropogenic actions on organic evolution. (CBSE Delhi 2013)
Answer:
Effect of anthropogenic actions on organic evolution:

1. Creation of breeds by artificial or selective breeding programs.
2. (a) Excess use of herbicides, pesticides, etc. has resulted in the selection of resistant varieties in a much lesser time.
   (b) Selection of drug-resistant microbes.
3. Survival of dark-winged (melanized) moths after industrialization in England.

Question 18.
Can we call human evolution adaptive radiation?
Answer:
No, we cannot call human evolution adaptive radiation. It is the case of descent with modification in which more advanced types are evolved from the simple forms. In the case of human evolution, there appears to be parallel evolution of the human brain and language.

Question 19.
State two postulates of Oparin and Haldane with reference to the origin of life. (CBSE Delhi 2017)
Answer:
Oparin and Haldane proposed that:

1. life originated from pre-existing non¬living organic molecules.
2. the diverse organic molecules were formed from inorganic constituents by chemical evolution.

Question 20.
Write the names of the following:
(i) A 15 mya primate that was ape-like
Answer:
Dryopithecus

(ii) A 2 mya primate that lives in East African grasslands (CBSE Delhi 2018)
Answer:
Australopithecus

Question 21.
(i) Write two differences between Homo erectus and Homo habilis.
Answer:
Differences between Homo erectus and Homo habilis:

Homo erectus	Homo habilis
1. Brain capacity is 900 cc.	1. Brain capacity is 900 cc.
2. Probably ate meat.	2. Probably ate meat.

(ii) Rearrange the following from early to late geologic periods: Carboniferous, Silurian, Jurassic. (CBSE Delhi 2019)
Answer:
Silurian, Carboniferous, Jurassic.

Evolution Important Extra Questions Long Answer Type

Question 1.
What are homologous organs? Give similar or different functions are catted examples. (CBSE 2016) homologous organs.
Answer:
Homologous organs: Organs that have a common origin, embryonic development, and the same fundamental structure but perform similar or different functions are catted homologous organs.

Examples of homologous organs:
1. The wings of bird and bat, flipper embryonic development, and same (fin) of whale and human forearm are fundamental structures but perform differently in forms because these have to perform different functions. Studies of the bones forming the skeleton of these organs would reveaL similarity in construction. In fact, these are the forms of forearms that have originated from pentadactyl forms and due to the different functions they are performing, they transformed into different forms.

2. In plants, the homologous organs may be a thorn of Bougainvillea or a tendriL of Cucurbita both arising in axillary position. Both have different forms depending on their function to perform.

Question 2.
How has the study of fossils helped in convincing scientists that organisms have come into existence through evolution? (CBSE Outside Delhi 2019)
Answer:
Fossils are important for man because of many reasons:

1. They provide evidence of past life.
2. They furnish direct and most convincing proofs in favor of organic evolution.
3. They afford some information of ancient environment and climate.
4. The most primitive forms of life are in the oldest rocks.
5. Ancient forms were simpler than those found today.
6. None of the plants and animals of the past were exactly similar to those found today.
7. A complete fossil record has been found in the evolution of horses.

Question 3.
Explain antibiotic resistance observed in light of Darwinian selection theory.
Answer:
Antibiotics were considered to be very effective against diseases caused by bacteria. But within two or three years of the introduction of antibiotics, new antibiotic-resistant bacteria appeared in the population. Sometimes a bacterial population happens to contain one or a few bacteria having mutations that make them resistant to the antibiotic. Such resistant bacteria survive and multiply quickly as the competing bacteria have died.

Soon the resistance-providing genes become widespread and the entire bacterial population becomes resistant. Some hospitals harbor antibiotic-resistant bacteria due to the extensive use of antibiotics.

Question 4.
How does natural selection operate according to Darwin’s theory of natural selection? (CBSE Delhi 2016, 2019 C)
Answer:
Natural selection operates in the following ways according to Darwin’s theory:

1. All plants and animals reproduce in a geometrical pattern. The number of organisms produced is much more than that can survive due to limited space and food.
2. Due to the same basic requirement, competition between organisms takes place and those who are better adapted to the environment survive while the rest die.
3. The individuals having useful variation overpower those without such variations. These variations are transmitted to future generations.

Question 5.
Distinguish between microevolution and macroevolution. Narrate the significance of population genetics in evolution.
Answer:
Evolution on the grand scale of geological time is called macroevolution, while evolution at the genetic level is microevolution. Microevolution is actually operative at genetic level change within a population. Significance of population genetics.

The gene frequency of a population is called population genetics. Evolution occurs within populations as the relative frequencies of different variations of DNA change over time. If genes change, then enzymes automatically change and represent two different forms of individuals and definitely result in evolution.

Question 6.
Compare and contrast the theories of evolution proposed by Darwin and Hugo De Vries. (CBSE Sample Paper 2018-19, Outside Delhi 2019)
Answer:

Darwin’s Theory of Natural Selection	De Vries Theory of Mutation
1. Minor variations cause evolution.	1. Mutation causes evolution.
2. Darwinian variations are small and directional.	2. Mutations are random and directionless.
3. Evolution is gradual.	3. Sudden mutations cause evolution.

Question 7.
How would the gene flow or genetic drift affect the population in which either of them happens to take place? (CBSE Delhi 2019)
Answer:
Gene flow is the transfer of genetic variations from one population to another. As a result of gene flow, the gene frequencies change in the original as well as in the new population. New genes or alleles are added to the new population and lost from the old population. If such a change in genes/alleles happens by chance, it is called genetic drift. In this case, the allelic frequency of the population will be affected. Such changes in allelic or gene frequencies lead to evolution, speciation, or founder effect.

Question 8.
Using the Internet and discussing with your teacher, trace the evolutionary stages of any one animal, say, a horse.
Answer:
The major evolutionary trend of horses:

1. General increase (with occasional decrease) in size.
2. The progressive loss of toes.
3. Lengthening of toes that are retained.
4. Lengthening of limbs in general.
5. Enlargement of the brain (especially cerebral hemisphere).
6. Increase in height.
7. Increase in the complexity of molar teeth and an enlargement of the last two and, eventually, the last three premolars until they came to resemble molars.

Question 9.
Summarise Milter’s simulation experiment for organic synthesis. Comment on its efficacy. (CBSE Delhi 2012)
Answer:
Miller’s experiment. Milter (1953) made the first successful simulation experiment to assess the validity of the claim for the origin of organic molecules. Miller sealed in a spark chamber a mixture of water, methane, ammonia, and hydrogen gas. He made arrangements for boiling water.

The trap in turn was connected with the flask for boiling water. After 18 days, a significant amount of simple major organic compounds, such as amino acids, such as glycine, alanine, and aspartic acid, and peptide chains, began to appear. Simple sugars, urea, and short-chain fatty acids were also formed. In the atmosphere, this spark is provided by U.V. light or other energy sources.

Stanley Miller’s Experiment in the artificial production of organic compounds.

Question 10.
With the help of an algebraic equation, how did Hardy-Weinberg explain that in a given population the frequency of occurrence of alleles of a gene is supposed to remain the same through generations? (CBSE Delhi 2018)
Or
Explain Hardy-Weinberg’s principle. (CBSE Delhi 2019 C)
Answer:
In a given population, one can find out the frequency of occurrence of alleles of a gene or a locus. This frequency is supposed to remain fixed and even remain the same through generations. Hardy-Weinberg’s principle stated it using algebraic equations. According to this principle, allele frequencies in a population are stable and are constant from generation to generation. The gene pool (total genes and their alleles in a population) remains constant. This is called genetic equilibrium.

Sum total of all the allelic frequencies is 1. Individual frequencies, for example, can be named as p, q, etc. In a diploid, p and q represent the frequency of allele A and allele a, respectively. The frequency of AA individuals in a population is simply p². This is simply stated in another way, i.e. the probability that an allele A with a frequency of p appears on both the chromosomes of a diploid individual is simply the product of the probabilities, i.e. p². Similarly of aa is q², of Aa 2pq. Hence, p² + 2pq + q² = 1. This is a binomial expansion of (p + q)². When the frequency measured is different from expected values, the difference (direction) indicates the extent of evolutionary change.

Disturbance in genetic equilibrium, or Hardy-Weinberg equilibrium, i.e. change of frequency of alleles in a population, would then be interpreted as resulting in evolution.

Question 11.
(i) Differentiate between analogous and homologous structures.
Answer:

Analogous organs	Homologous organs
(i) Organs that are structurally dissimilar but functionally similar are called analogous organs. Example: wings of birds and insects.	(i) Organs that are structurally similar but functional dissimilar are called homologous organs. Example: forelimbs of frog, lizard, bird, bat, horse, man, etc.
(ii) They lead to convergent evolution.	(ii) They lead to divergent evolution.

(ii) Select and write analogous structures from the list given below:
(o) Wings of butterfly and birds
(b) Vertebrate hearts
(c) Tendrils of Cucurbita and thorns of Bougainvillea
(d) Tubers of sweet potato and potato (CBSE Delhi 2018)
Answer:
(a) Wings of butterflies and birds.
(b) Tubers of sweet potato and potato.

Question 12.
Write thecharacteristicsofRamapithecus, Dryopithecus, and Neanderthal man. (CBSE Delhi 2017)
Answer:
Characteristics of Ramapithecus:

• They evolved around 15 mya.
• They were more man-like, walked more erect, and had teeth like modern men.

Characteristics of Dryopithecus:

• They evolved around 5 mya.
• They were ape-like, having hairy arms and legs of the same length, large brains. They used to eat soft fruits and leaves and walked like gorillas and chimpanzees.

Characteristics of Neanderthal Man:

• They evolved around 1,00,000-40,000 years ago.
• Fossil found in east and central Asia had brain size 1400 cc. They used hides to protect their body. They buried their dead.

Question 13.
How does the process of natural selection affect Hardy-Weinberg equilibrium? List the other four factors that disturb the equilibrium. (CBSE Outside Delhi 2013)
Or
Write Hardy-Weinberg principle.
Or
How can Hardy-Weinberg equilibrium be affected? Explain giving three reasons. (CBSE Delhi 2018C)
Answer:
Hardy-Weinberg Principle states that the sum of allelic frequencies in a population is stable and is constant from generation to generation, i.e. the gene pool (total genes and their alleles) in a population remains constant. This is called genetic equilibrium. The sum total of all the allelic frequencies is

Hardy-Weinberg’s Equilibrium p²+ q² + 2pq =

Five factors that influence these values are:
The five factors which affect Hardy- Weinberg’s equilibrium is as follows:

1. Gene migration: When some individuals of a population migrate to other populations or when certain individuals come into a population (i.e. migration and immigration), some genes are lost in the first case and added in the second.
2. Genetic drift: Random changes in the allele frequencies of a population occurring only by chance constitute genetic drift. The change in allele frequency may become so drastically different that they form a new species.
3. Mutations: The mutations are random and directionless. They are sufficient to create a considerable genetic variation for speciation to occur.
4. Recombination: New combinations of genes occur due to crossing over in meiosis during gametic formation.
5. Natural selection: It is the most critical evolutionary process that leads to changes in allele frequencies
   and favors adaptation as a product of evolution.

Question 14.
Define genetic drift. How does it produce the founder effect and genetic bottleneck?
Or
How does the original drifted population become a founder? (CBSE 2019 C)
Answer:
Genetic drift: Random change occurring in the allele frequency by chance alone is called genetic drift. It is due to habitat fragmentation, isolation, natural calamities, or any epidemics.

Founder effect: When a section of the population gets separated from the original population, then this section becomes genetically different from the original population due to a change in alleles frequency. The original population becomes the founder of the new population. This is called the founder effect which is the result of genetic drift, i.e. by chance. Genetic bottleneck.

When in a season one population died leaving few individuals of the population which become the founder of the new population, then it will produce only a few genes by selection only, i.e. by chance new population is emerged and it is similar to a bottle in which only certain population is allowed to flow as in the neck of a bottle.

Bottleneck effect

Question 15.
How does Darwin’s theory of natural selection explain new forms of life on earth? (CBSE 2008, 2016)
Answer:
Darwin’s Theory of evolution may be summed up as follows:
Darwin’s Theory of natural selection. Charles Darwin (1809 – 1882), a naturalist, proposed a theory to explain the process of evolution. His theory was published in his famous book “Origin of Species” published in 1858.

His theory of natural selection is termed Darwinism:

• Rapid multiplication
• Struggle for existence
• Variations
• Natural selection or survival of the fittest
• Inheritance of useful variations
• Origin of new species.

Evidence in favor of Darwin’s theory: Darwin’s theory is supported by natural selection, phenomena of mimicry and protective coloration, and the correlation between nectaries of flowers and proboscis of pollinating insects.

Darwin’s theory fails to explain the perpetuation of vestigial organs and over-specialization of organs.
Darwin’s theory has since been modified in the light of progress in genetics.

Question 16.
Describe the present-day concept of evolution.
Answer:
1. Modern concept of evolution: The modern concept of evolution is a modified form of Darwin’s theory of natural selection and is often called Neo-Darwinism. It comprises genetic variation, natural selection, and isolation.
(a) Mutations: These have been recognized as the ultimate source of biological changes and hence the raw material of evolution. The mutation in chromosomes may be due to changes in structure, number, or gene.

(b) Gene Recombination takes place during crossing over in meiosis. New combinations of genes produce new phenotypes.

(c) Hybridisation is the intermingling of the genes of the members of closely related species.

(d) Genetic drift is the elimination of the genes of some original characteristics of a species by extreme reduction due to different reasons.

In Monoparental reproduction, only chromosomal and gene mutation are sources of genetic variation,

2. Natural Selection: If differential reproduction (i.e. some individuals produce abundant offspring, some only a few, and some organisms none) continues for many generations, genes of the individuals which produce more offspring will become predominant in the gene pool of the population. Thus natural selection occurs through differential reproduction in successive generations. The migration of individuals from one to another population is an accessory factor for speciation (origin of new species).

3. Isolation: By selecting the most suitable genotypes, natural selection guides different populations into different adaptive channels. The reproductive isolation between the populations due to certain physical barriers or others leads to the formation of new species. Isolation plays a significant role in evolution.

Question 17.
(i) Name the primates that lived about 15 million years ago. List their characteristic features.
Answer:
Primates Dryopithecus and Ramapithecus lived about 15 mya.

Features:
(a) Hairy and walked like gorillas and chimpanzees. Height up to 4 feet but walked upright.

(ii) (a) Where was the first man-like animal found?
Answer:
Ethiopia and Tanzania

(b) Write the order in which Neanderthals, Homo habilis, and Homo erectus appeared on the earth. State the brain capacity of each one of them.
Answer:

• Homo habilis – 700 cc
• Homo erectus – 900 cc
• Neanderthals man – 1300-1600 cc

(c) When did modern Homo sapiens appear on this planet ? (CBSE Delhi 2011)
Answer:
Homo sapiens appeared about 34000 years ago.

Very Importance Figures:

(A) Foretimbs of vertebrates as homologous organs.
(B) AnaLogous organs. Wings of insect and bird.

Darwin finches

Adaptive radiations of Australian marsupials

Kinds of selection

Here we are providing Class 12 Accountancy Important Extra Questions and Answers Chapter 7 Issue and Redemption of Debentures. Accountancy Class 12 Important Questions and Answers are the best resource for students which helps in class 12 board exams.

Class 12 Accountancy Chapter 7 Important Extra Questions Issue and Redemption of Debentures

Issue and Redemption of Debentures Important Extra Questions Very Short Answer Type

Question 1.
What is meant by ‘Issue of Debentures as Collateral Security’ ? (CBSE Outside Delhi 2019)
Answer:
Debenture issued as secondary security/additional security over and above the primary security is known as Issue of Debentures as Collateral Security.

Question 2.
State the provision of the Companies Act, 2013 for the creation of Debenture Redemption Reserve. (CBSE Outside Delhi 2019)
Answer:
Where a company has issued Debentures, it shall create a DRR equivalent to at least 25% of the nominal value of debentures outstanding for the redemption of such debentures.

Question 3.
Profit arisen on account of buying an existing business at profit is transferred to which account?
Answer:
Capital Reserve.

Question 4.
Name the debentures which continue till the continuity of the company.
Answer:
Irredeemable.

Question 5.
Name the debenture which may be converted into equity shares at specified time.
Answer:
Convertible debentures.

Question 6.
Name the debentures which have charge on the company’s assets.
Answer:
Secured debentures (also known as mortgaged debentures).

Question 7.
When a debenture is issued at a price less than its face value or nominal value, what does such difference represent?
Answer:
Discount.

Question 8.
When debentures are redeemed more than the face value of debenture, What does the difference between face value of debenture and redeemed value of debenture is called?
Answer:
Premium on redemption of debentures.

Question 9.
Name the head under which ‘discount on issue of debentures’ appears in the Balance Sheet of a company.
Answer:
Head ‘Current Assets’ and sub-head ‘Other Current Assets’.

Question 10.
What does the repayment or discharge of liability on account of debentures is called?
Answer:
Redemption of debentures.

Question 11.
Under which head is the ‘Debenture Redemption Reserve’ shown in the Balance Sheet?
Answer:
‘Reserve & Surplus’.

Question 12.
When the company issues debentures to the lenders as an additional/secondary security, in addition to other assets already pledged/ some primary security. What does such issue of debentures is called? (CBSE 2018)
Answer:
Issue of dedentures as collateral security.

Question 13.
It is a written instrument acknowledging a debt under the common seal of the company, name the term.
Answer:
Debenture.

Question 14.
State an exception to the creation of Debenture Redemption Reserve as per Companies (Share Capital and Debentures) Rules 18(7). (CBSE Sample Paper 2014 Modified)
Answer:
Banking Companies

Question 15.
Mention the type of debentures whose ownership passes on mere delivery of debenture certificates.
Answer:
Bearer debentures.

Question 16.
Can ‘Securities Premium’ be used as working capital?
Answer:
No.

Question 17.
A company purchased net assets of another company worth ₹ 20,00,000 and issued debentures worth ₹ 19,00,000. What type of profit has the buying company made?
Answer:
Capital Profit.

Question 18.
Vikas Infrastructure Ltd. has issued 50,000, 10% debentures of ₹ 100 each at par redeemable after the end of 7th year. Mention the amount by which the company should create Debenture Redemption Reserve as per Companies (Share Capital and Debentures) Rules 2014 before starting redemption of debenture. Answer with giving reason.
Answer:
₹ 12,50,000.

Question 19.
Axis Ltd. has issued 8,000, 10% debentures of₹ 100 at a premium of ₹ 5 per debenture redeemable at the end of 5 years. The company has created Debenture Redemption Reserve with ₹ 4,00,000. After 5 years, the company redeemed all the debentures ₹ Where should the company transfer the amount of Debenture Redemption Reserve?
Answer:
General Reserve.

Issue and Redemption of Debentures Important Extra Questions Short Answer Type

Question 1.
Garvit Ltd. invited applications for issuing 3,000, 11% Debentures of₹ 100 each at a discount of 6%. The full amount was payable on application. Applications were received for 3,600 debentures. Applications for 600 debentures were rejected and the application money was refunded. Debentures were allotted to the remaining applicants.
Pass the necessary journal entries for the above transactions in the books of Garvit Ltd. (CBSE Delhi 2019)
Answer:

Question 2.
On 1st April 2015, P Ltd. Issued 6,000 12% Debentures of ₹ 100 each at par redeemable at a premium of 7%. The Debentures were to be redeemed at the end of third year. Prepare Loss on issue of 12% Debentures Account. (CBSE Delhi 2019)
Answer:

Question 3.
Unilink Ltd. (An unlisted company) had outstanding ₹ 12,00,000, 9% debentures on 1st April, 2020 redeemable at a premium of 8% in two equal annual instalments starting from 31st March, 2022. The company had a balance of₹ 1,20,000 in Debenture Redemption-Reserve on 31st March, 2020. Pass the necessary journal entries for redemption of debentures in the books of Unilink Ltd. for the year ended 31st March, 2022. . (CBSE Delhi 2019, Modified)
Answer:


Note: This question has been updated as per Companies (Share Capital and Debentures) Amendment Rules, 2019.

Question 4.
Krishna Ltd. (An unlisted company) had outstanding 20,000,9% debentures of₹ 100 each on 1st April, 2014. These debentures were redeemable at a premium of 10% in two equal instalments starting from 31 st March, 2021. The company had a balance of ₹2,00,000 in Debenture Redemption Reserve on 31 st March, 2020.
Pass necessary journal entries for redemption of debentures in the books of Krishna Ltd. for the year ended 31st March, 2018. (CBSE Delhi 2019, Modified)
Answer:

Note: This question has been updated as per Companies (Share Capital and Debentures) Amendment Rules, 2019.

Question 5.
On 1st April, 2013 Anushka Ltd. (An unlisted companies) issued ₹70,00,000, 9% debentures of ₹ 100 each at par, redeemable at a premium of 5% on 31 st march, 2021. The company created the necessary, minimum amount of debenture redemption reserve and purchased debenture redemption reserve investments. The debentures were redeemed on 31 st March, 20121. Pass necessary journal entries for the redemption of debentures, in the books of the company.
(CBSE Delhi 2019, Modified)
Answer:

Note: This question has been updated as per companies (Share capital and debentures) Amendment Rules, 2019.

Question 6.
Pass necessary journal entries and prepare 9% Debentures Account for the issue of 7,500,9% Debentures of ₹ 50 each at a discount of 6%, redeemable at a premium of 10%. (CBSE Delhi 2019, Modified)
Answer:

Question 7.
Krishna Ltd. had (an unlisted company) outstanding 20,000, 9% debentures of₹ 100 each on 1st April, 2014.. These debentures were redeemable at a premium of 10% in two equal instalments starting from 31st March, 2021.
The company had a balance of₹ 1,80,000 in Debenture Redemption Reserve on 31st March, 2020.
Pass necessary journal entries for redemption of debentures in the books of Krishna Ltd. for the year ended 31 st March, 2021. (CBSE Outside Delhi 2019, Modified)
Answer:


Note: This question has been updated as per companies (Share capital and debentures) Amendment Rules, 2019.

Question 8.
On 1 st April, 2013 Anushka Ltd. (unlisted company) issued ₹70,00,000, 9% debentures of ₹ 100 each at par, redeemable at a premium of 5% on 31 st march, 2021. The company created the necessary, minimum amount of debenture redemption reserve and purchased debenture redemption reserve investments. The debentures were redeemed on 31st March, 2021.
Pass necessary journal entries for the redemption of debentures, in the books of the company.
Answer:

Note: This question has been updated as per companies (Share capital and debentures) Amendment Rules, 2019.

Question 9.
Complete the following Journal Entries

Answer:

Question 10.
V K Limited purchased machinery from Modem Equipment Manufacturers Limited. The company paid the vendors by issue of some equity shares and debentures and the balance through an acceptance in then- favour payable after three months. The accountant of the company, while Journalising the above mentioned transactions, left some items blank. You are required to fill in the blanks.

Answer:

Question 11.
‘sangam Wooilens Ltd’, Ludhiana, are the and exporters of garments. The company decided to distribute free of cost oUes. garments to 10 villages of lahual and spiti district of Himachal Pradesh. The company also decided to employ 50 young persons from these villages in its newly established factory. The company issued 40,000 equity shares of’ 10 each and 1,000 9% debentures of’ 100 each to the vendors for the purchase of machinery of’ 5,00,000.
Pass necessary Journal Entries. (Dehli 2015, Modified)
Answer:

Question 12.
Anirudh Limited (Listed company) has 4,000, 8% debentures of₹ 100 each due for redemption on March 31, 2022. The company has a DRR of ₹ 20,000 on that date. Assuming that no interest is due. Record the necessary journal entries at the time of redemption of debentures.
Answer:

Note: This question has been updated as per companies (Share capital and debentures) Amendment Rules, 2019.

Question 13.
R. Ltd. offered 20,00,000,10% Debenture of₹ 200 each at a discount of redeemable at premium of 8% after 9 years. Record necessary entries in the book of R. Ltd.
Answer:

Question 14.
Journalise the following:
(i) A debenture issued at ₹ 95, repayable at ₹ 100;
(ii) A debenture issued at ₹ 95, repayable at ₹ 105; and
(iii) A debenture issued at ₹ 100 repayable at ₹ 105;
The face value of debenture in each of the above cases is ₹ 100.
Answer:

Question 15.
A Company issues the following debentures:
(i) 10,000,12% debentures of₹ 100 each at par but redeemable at premium of 5% after 5 years;
(ii) 10,000,12% debentures of₹ 100 each at a discount of 10% but redeemable at par after 5 years;
(iii) 5,000,12% debentures of₹ 1,000 each at a premium of 5% but redeemable at par after 5 years;
Answer:

Question 16.
X Ltd. invited applications for issuing 1000,9% debentures of₹ 100 each at a discount of 6%. Applications for 1,200 debentures were received. Pro-rata allotment was made to all the applicants. Pass necessary Journal Entries for the issue of debentures assuming that the whole amount was payable with applications. [Delhi 2017]
Answer:

Question 17.
Z Ltd. purchased machinery from K Ltd. Z Ltd paid K Ltd as follows:
(i) By issuing 5,000 equity shares of ₹ 10 each at a premium of 30%.
(ii) By issuing 1000, 8% Debentures of₹ 100 each at a discount of 10%.
(iii) Balance by giving a promissory note of ₹ 48,000 payable after two months.
Pass necessary journal entries for the purchase of machinery and payment to K Ltd. in the books of Z Ltd. [Delhi 2017]
Answer:

Question 18.
K K Limited obtained a loan of₹ 10,00,000 from State Bank of India @ 9 % interest. The company issued ₹ 15,00,000, 9 % debentures of₹ 100/- each, in favour of State Bank of India as collateral security. Pass necessary Journal entries for the above transactions:
(i) When company decided not to record the issue of 9 % Debentures as collateral security.
(ii) When company decided to record the issue of 9 % Debentures as collateral security. (CBSE Sample Paper 2018-19, 2017-18)
Answer:

Question 19.
Explain with an imaginary example how issue of debenture as collateral security is shown in the balance sheet of a company when it is recorded in the books of accounts. (CBSE Sample Paper 2016, 2017)
Answer:
Alfa Ltd. obtained Loan of 1,00,000 from Indian Bank and issued 1200, 10% Debentures of 100 each as Collateral security.
Treatment: An extract of Balance sheet of Alfa Ltd.

Question 20.
KTR Ltd., issued 365, 9% Debenture of 7’1,000 each on 4.3.2016. Pass necessary journal entries for the issue of debenture in the following situations : (CBSE Outside Delhi 2016)
(i) When debentures were issued at per redeemable at a premium of 10%.
(ii) When debentures were issued at 6% discount redemable at 5% premium.
Answer:

Question 21.
VKR Ltd. issued 975; 9% Debentures of 7 500 each on 4.3.2016. Pass necessary journal entries for the issue of debentures under the following situations:
(i) When debentures were issued at a premium of 10% redeemable at a premium of 6%.
(ii) When debentures were issued at a par redeemable at 9% premium. (CBSE Outside Delhi 2016)
Answer:

Question 22.
BG. Ltd. issued 2,000, 12% debentures of (100 each on 1st April 2012. The issue was fully subscribed. According to the terms of issue, interest on the debentures is payable half-yearly on 30s1 September and 31st March and the tax deducted at source is 10%. Pass necessary journal entries related to the debenture interest for the half-yearly ending 3151 March, 2013 and transfer of interest on debentures of the year to the Statement of Profit & Loss. . (CBSE Delhi 2014, Set I, II)
Answer:


Question 23.
Jan Dhan Bank, an All India Financial Institution, had 10,000,12% debentures of₹ 100 each, outstanding as at 31st March, 2022. These debentures were due for redemption on 30th June, 2023. Pass necessary Journal Entries for redemption of debentures. Also, state the amount of Debenture Redemption Reserve to be created for the purpose of redemption. (CBSE Sample Paper 2018-19, Modified)
Answer:

Note:
According to Section 71(4) of the Companies Act, 2013 and Companies (Share Capital & Debentures) Amendment Rules, 2019, an All India Financial Institution is not required to create Debenture Redemption Reserve.

Question 24.
Raghuveer Limited created 10,00,000, 8% debentures stock which was issued as follows to:
1. Sundry subscribers for cash at 90%
2. Creditors for ₹ 2,00,000 capital expenditure in satisfaction of his claim
3. Bankers as collateral securities for a bank loan
worth ₹ 20,00,000 for which principal security is business premises worth
The issue (1) and (2) are redeemable at the end of 10 years at par. State how the debenture stock be dealt with while preparing the balance sheet of a company.
Answer:

Question 25.
Hassan Limited took a loan of ₹ 30,00,000 from a bank against primary security worth ₹ 40,00,000 and . issued 4,000, 6% debentures of₹ 100 each as a collateral security. The company again after one year took a loan of ₹ 50,00,000 from bank against plant as primary security and deposited 6,000, 6% debentures of₹ 100 each as collateral security. Record necessary journal entries and prepare balance sheet of the company.

Answer:

Question 26.
Meghnath Limited took a loan of ₹ 1,20,000 from a bank and deposited 1,400, 8% debentures of ₹ 100 each as collateral security along with primary security worth ₹ 2 Lakhs. Company again took a loan of ₹ 80,000 after two months from a bank and deposited 1,000, 8% debentures of ₹ 100 each as collateral security. Record necessary journal entries and prepare a balance sheet of a company.
Answer:

Question 27.
Diwakar Enterprises Ltd. issued 10,00,000, 6% debentures on April 1, 2008. Interest is paid on September 30, 2012 and March 31, 2013.
Record necessary journal entries assuming that income tax is deducted @ 30% of the amount of interest.
Answer:

Question 28.
Laser India Ltd. issued 7,00,000, 8%. debentures of₹ 100 each at par. Company deducts income tax from the interest of these debentures at source. Interest is to be paid on these debentures half yearly on September 30 and March 31, every year. Amount of income tax deducted half yearly is ₹ 2,80,000.
Answer:

Question 29.
B. Ltd. purchased assets of the book value of ₹ 4,00,000 and took over the liability of ₹ 50,000 from Mohan Bros. It was agreed that the purchase consideration settled at ₹ 3,80,000 be paid by issuing debentures of₹ 100 each.
What journal entries will be made in the following three cases, if debentures are issued: (a) at par; (b) at a discount of 10%, (c) at a premium of 10%₹ It was agreed that a fraction of debentures be paid in cash.
Answer:

Question 30.
B. Ltd. issued 1,000,12% debentures of₹ 100 each on January 01,2008 at a discount of 5% redeemable at a premium of 10%.
Give journal entries relating to the issue of debentures and debentures interest for the period ending December 31,2008 assuming that interest is paid half yearly on June 30 and December 31 and tax deducted at sources is 10%. B. Ltd. follows calendar year as its accounting year.
Answer:

Issue and Redemption of Debentures Important Extra Questions Long Answer Type

Question 1.
Journalise the following transactions
(a) Mehar Ltd. issued ₹ 1,00,000, 12% Debentures of ₹ 100 each at a premium of 5% redeemable at a premium of 2%
(b) 12% Debentures • were issued at a discount of 10% to a vendor of machinery for payment of ₹ 9,00,000
(c) Issue of 10,000 11% debentures of₹ 100 each as collateral in favour of State Bank of India. Company
opted to pass necessary entry for issue of debentures. (CBSE Sample Paper 2019-20)
Answer:

Question 2.
Faith and Belief Ltd has total redeemable debentures of₹ 5,00,000. It decides to redeem these debentures in two instalments of₹ 3,00,000 and ₹ 2,00,000 on December 31st 2021 and March 31st 2023 respectively. Assuming that the Company has sufficient funds in Debenture Redemption Reserve Account, pass necessary journal entries for the year ending March 31st 2020. (CBSE Sample Paper 2019-20, Modified)
Answer:


Note:
This question has been updated as per companies (Share capital and debentures) Amendment Rules, 2019.

Question 3.
On 1st April, 2016, Ganesh Limited (An Unlisted Company) acquired assets of₹ 6,00,000 and took over liabilities of₹ 70,000 of Sohan Ltd. at an agreed value of₹ 6,60,000 Ganesh Ltd. issued 12% Debentures of ₹ 100 each at a premium of 10% in Ml satisfaction of purchase consideration. The debentures were redeemable after three years at a premium of 5%. The company decided to transfer the minimum required amount to Debenture Redemption Reserve of 31st March, 2022. It also made the required investment in Government securities earning interest @ 10% p.a. on IstApril, 2022. Tax was deducted on interest earned @ 10%.
Ignoring entries relating to writing off loss on issue of debentures and interest paid on debentures, pass the necessary journal entries to record the issue and redemption of debentures. (CBSE Compt. 2019, Modified)
Answer:

Question 4.
On 1st April, 2016 X Ltd. (An unlisted company) issued 1000; 9% debentures of₹ 100 each at a premium of ₹ 5 per debenture and redeemable on 31 st March, 2022 at a premium of ₹ 8 per debenture. The company created the minimum amount of debenture redemption reserve as per the amended provisions of the Companies Act, 2013 on 31 st March, 2021 and made investments in 8% p.a. fixed deposits in State Bank of India on 1 st April, 2021.
Excluding the entries for writing off loss on issue of debentures and interest on debentures, pass necessary journal entries for the above transactions in the books of X Ltd. (CBSE Compt. 2019, Modified)
Answer:


————-

Question 5.
Nena Limited issued 50,000, 10% debentures of₹ 100 each on the basis of the following conditions:
(a) Debentures issued at par and redeemable at par.
(b) Debentures issued at discount @ 5% & redeemable at par.
(c) Debentures issued at a premium @ 10% & redeemable at par.
(d) Debentures issued at par & redeemable at premium @ 10%.
(e) Debentures issued at discount of 5% and redeemable at a premium of 10%.
(f) Debentures issued at premium of 6% and redeemable at a premium of 4%.
Record necessary journal entries in the above mentioned cases at the time of issue and redemption of debentures.
Answer:

Question 6.
Z. Limited (An unlisted company) issued, 2,000, 14% debentures of₹ 100 each on January 01, 2020 at a discount of 10%, redeemable at a premium of 10% in equal annual Drawings in 4 years out of profits. Give journal entries both at the time of issue and redemption of debentures.
(Ignore the treatment of loss on issue of debentures and interest.)
Answer:

Question 7.
On 1-4-2015 K.K. Ltd. issued 500, 9% Debentures of ₹ 500 each at a discount of 4%, redeemable at a premium of 5% after three years.
Pass necessary Journal Entries for the issue of debentures and debenture interest for the year ended 31 -3-2016 assuming that interest is payable on 30th September and 31 st March and the rate of tax deducted at source is 10%. The company closes its books on 31st March every year. [Delhi 2017]
Answer:

Question 8.
X. Ltd. issued 15,000, 10% debentures of₹ 100 each. Give journal entries and the Balance Sheet in each of the following cases:
(i) The debentures are issued at a premium of 10%.
(ii) The debentures are issued at a discount of 5%.
(iii) The debentures are issued as a collateral security to bank against a loan ₹ 12,00,000.
(iv) The debentures are issued to a supplier of machinery costing ₹ 13,50,000.
Answer:

Question 9.
On 1st April, 2018, KK Ltd. (An unlisted company) invited applications for issuing 5,000 10% debentures of₹ 1,000 each at a discount of 6%. These debentures were payable at the end of 3rd year at a premium of 10%. Applications for 6,000 debentures were received and the debentures were allotted on pro-rata basis to all the applicants. Excess money received with applications was refunded. The directors decided to transfer the minimum amount to Debenture Redemption Reserve on 31.3.2020. On 1.4.2020, the company invested the necessary amount in 9% bank fixed deposit as per the amended provisions of the Companies Act, 2013. Tax was deducted at source by bank on interest @ 10% p.a. Pass the necessary journal entries for issue and redemption of debentures. Ignore entries relating to writing off loss on issue of debentures and interest paid on debentures. (CBSE 2018, Modified)
Answer:

Question 10.
Ruchi Ltd (An unlisted company) issued 42,000,7% Debentures of 100 each on 1st April, 2015, redeemable at a premium of 8% on 31st March 2021. The Company decided to create required Debenture Redemption Reserve on 31st March 2020. The company invested the funds as required by law in a fixed deposit with State Bank of India on 1st April, 2021 earning interest @ 10% per annum. Tax was deducted at source by the bank on interest @ 10% per annum. Pass necessary Journal Entries regarding issue and redemption of debentures.
(CBSE Sample Paper 2016, 2017, Modified)
Answer:

Question 11.
(Lump-sum Method): Alibaba Ltd. (An unlisted company) issued 20,000, 9% debentures of ₹ 50 each on April 1, 2022 redeemable at par on March 31, 2022. All the debentures were subscribed and allotted. Investment of the required amount in securities is subject to deduction of 10% tax at source. Pass journal entries for issue and redemption of debentures assuming required investments were made in 6% specified securities.
Answer:

Question 12.
(Lump-sum Method): On April 1, 2020, Nelson and Tubro Ltd. (An unlisted company) issued 10,000, 10% debentures of₹ 100 each redeemable at 5% premium on March 31, 2022. Debentures were fully subscribed and allotted. Pass necessary journal entries for issue and redemption of debentures assuming necessary amount was invested in 7 % specified securities.
Answer:


Note: This question has been updated as per companies (Share capital and debentures) Amendment Rules, 2019.

Question 13.
(Instalments or Draw a Lot Method): Neelgiri Limited issued 6,000, 10% debentures of ₹ 100 each on April 01, 2018 redeemable in 3 three equal instalments commeucing with March 31, 2021. The board of directors decided to transfer the required amount to Debenture Redemption Reserve in 2 equal instalments. Company also complied with Companies (Share Capital and Debentures) Amendment Rules, 2019.
Answer:

Here we are providing Class 12 Business Studies Important Extra Questions and Answers Chapter 9 Financial Management. Business Studies Class 12 Important Questions are the best resource for students which helps in class 12 board exams.

Class 12 Business Studies Chapter 9 Important Extra Questions Financial Management

Financial Management Important Extra Questions Short Answer Type

Question 1.
What are the various factors affecting Financial Planning?
Answer:
A financial plan should be prepared very carefully because it has a long-term impact on the working of an enterprise. A financial plan is affected by a number of factors. All these factors should be’ taken into consideration while preparing a financial plan.

1. Nature of Business: The nature of business plays a decisive role in formulating a financial plan. A manufacturing business requires more amount of long-term funds than a trading business. In addition to it, the factors such as stability and regularity of income, future prospects of growth, seasonal fluctuations, assets structure, etc. affect the financial requirements as well as sources of finance.

2. Degree of Risk: The risk involved in the business also plays an important role while planning the sources of finance. A firm whose sales and earnings are subject to wide fluctuations runs the risk of not being able to meet the required payments in respect of interest and repayment of loans. Clearly, such firms should use more amount of their own funds and rely less on debt. On the other hand, the enterprises with stable sales and earnings can employ more amount of debts and hence can take the advantage of trading on equity.

3. Standing of the concern: Credit standing of concern among investors affects financial planning to a great extent. The credit standing of concern is determined by a number of factors such as the age of the firm, its past performance, size, market area, the reputation of management, etc.

4. Plans for future Growth: The plans for growth and expansion of the firm in near future are considered while formulating a financial plan. The financial plan should be developed in such a way as to facilitate required funds without much difficultly.

5. Alternative Sources of Finance: Since finance can be procured from a number of sources, the pros and cons of all the sources should be properly considered while choosing the proper sources of finance. The sources should be able to provide adequate funds to meet the requirements of the business.

6. Attitude of Management: The attitude of management towards risk and control of the business affects financial planning to a great extent. If the management is of risk-taking nature, it would employ more amount of borrowed funds. On the contrary, if it is of conservative nature it will employ more amount of equity capital. From the control point of view, if the management desires to keep full control of the enterprise, it will not issue fresh equity shares so that the new shareholders may not control the enterprises.

7. Government Policies and Control: The financial plan of a company is affected by the rules and regulations framed by the Government stock exchanges and financial institutions from time to time. The terms of issue of shares and debentures, interest rates, dividend payments, etc. are governed by the rules framed by the government periodically. Permission of the Securities and Stock Exchange Board of India (SEBI) is also required for the issue of shares and debentures.

8. Changes in Technology, Consumer Tastes, and Competitive Factors: Rapid innovations are taking place in every field nowadays. A financial plan is adequately affected by changes in technology, consumer preferences, degree of competition, and general economic conditions.

Question 2.
Explain in brief the various steps in financial planning.
Answer:
Following steps should be taken for preparing a financial plan:
1. Determination of Financial Objectives: For the purpose of preparing an effective financial plan first of all the financial objectives of a firm should be clearly determined. The financial objectives should be divided into short-term objectives as well as long-term objectives. The short-term objectives may include maintaining the liquidity of funds, maintaining the market standing of the firm and proper maintenance of sales, etc.

On the other hand, the long-term objectives may include the achievement of maximum efficiency of factors of production at minimum cost and the maximization of shareholder’s wealth. The objectives should be clearly defined so that they can be used as guidelines for determining the 1 policies and procedures.

2. Formulation of Financial Policies: The second step in financial planning is the formulation of financial policies. Financial policies act as guidelines for the f procurement, allocation, and effective utilization of funds of the organization. Financial policies are framed by the top management with the advice of the financial manager. The policies may be regarding capitalization, capital structure, trading on equity, fixed assets management, working capital management, dividend distribution, etc.

3. Formulation of Procedures: The policies laid down must be clarified in the form of detailed procedures. Each subordinate must know what he is required to do. Procedures are essential to ensure the consistency of actions. In financial procedures, financial executives decide about the control system, establish the standards of performance and compare the actual performance with the standards to ascertain the deviations and their causes. Thereafter, necessary steps are taken to control the deviations.

4. Provision of Flexibility: The objectives, policies, and procedures laid down as above constitute the financial plan of a business. Financial planning is a continuous process and hence there should be proper flexibility in the financial objectives, policies, and procedures so that these may be revised or thoroughly overhauled according to the changing circumstances.

Question 3.
Explain the major characteristics or Principles of a sound financial plan.
Answer:
An ideal financial plan must be based on the principles or qualities mentioned below:
1. Simplicity: Financial plan should be so simple that it may be easily understood by everyone. It should have a simple capital structure capable of being managed easily. The type of securities issued should be kept at a minimum because various types of securities will create unnecessary suspicion in the minds of investors.

2. Foresight: The financial plan should be prepared to keep in view the future needs of the business. It should take into consideration the future demand of the company’s products, the future scale of operations, technological innovations, and various other changes. A financial plan should be able to meet the future requirements of fixed as well as working capital.

3. Optimum use of Funds: An ideal financial plan should always aim at the best possible and intensive use of all available resources of finance. The business should neither be starved of funds nor it should have a surplus or idle funds. Unnecessary idle funds are as bad as inadequate funds. A proper balance should also be kept between the short-term and long-term funds of the business.

4. Flexibility: A financial plan should be sufficiently flexible. It should be possible for a company to change its financial plan with minimum cost and delay if warranted by changed circumstances. The company should be able to substitute one form of financing for another to economize the use of funds. The financial plan should allow a scope for adjustments as and when a new situation arises like recession, boom, etc. A rigid financial plan can easily become a burden rather than a 1 technique of financial management.

5. Liquidity: Liquidity is the ability of the enterprise to pay off its day-to-day expenses and other short-term liabilities on time. The financial plan should provide sufficient liquidity of funds as it will ensure the creditworthiness and goodwill of the enterprise. Adequate liquidity in the \ financial plan increases its flexibility also.

6. Economical: Financial plan must be prepared in such a way that the cost of capital is minimum. The average cost of capital will be minimum when a fair 1 balance is maintained between debt funds and owned capital. Also, the financial plan should involve minimum expenses on the issue of capital such as underwriting Commission, brokerage, etc.

7. Contingencies: A financial plan should keep-in view the requirement of funds for contingencies. Contingencies mean the requirement of funds for unseen: events.

8. Adequate system of Control: A financial plan should establish and maintain a proper system of financial control.

9. Suitable to the Organisation structure: A financial plan should be in accordance with the size and organizational structure of the firm.

Question 4.
Define the nature and types of working capital.
Answer:
Along with the fixed capital, almost every business requires working capital though the extent of working capital requirement differs in different businesses. Working capital is needed for running the day-to-day business activities. When a business is started, working capital is needed for purchasing raw materials. The raw’ material is then converted into finished goods by incurring some additional costs on it.

Now goods are sold. Sales do not convert into cash instantly because there is invariably some credit sales. Thus, there exists a time, lag between sales of goods and receipt of cash. During this period, expenses are to be incurred for continuing the* business operations.

For this purpose working capital is needed, Therefore, sufficient working capital is needed which shall be involved from the purchase of raw materials to the realization of cash.

The time period which is required to convert raw materials into finished goods and then into cash is known as the operation cycle or cash cycle. The need for working capital can also be explained with the help of the operating cycle.

The operating cycle of a manufacturing concern involves five phases:

1. Conversion of cash into raw material
2. Conversion of raw material into work-in-progress
3. Conversion of work-in-progress into finished goods
4. Conversion of finished goods into debtors by credit sales
5. Conversion of debtors into cash by realizing cash from them.

Thus the operating cycle starts from cash, finishes at cash, and then again restarts from cash. The need for working capital depends upon the period of the operation cycle. Greater the period, more will be the need for working capital. The period of operation cycle in a manufacturing concern is greater than a period of operating cycle in a trading concern because in trading units cash is directly converted into finished goods.

Diagram: Operating Cycle (Nature of Working Capital)

Because of the time involved in an operating cycle, there is a need, for working capital in the form of current assets. Firms have to keep I adequate stock of raw materials to avoid the risk of non-availability of raw materials. Similarly, the concern must have adequate stock of finished goods to meet the demand in the market on a continuous basis and to avoid being out of stock. Concern also has to sell finished goods on credit due to competition which necessitates the money tied up in debtors. Y and bills receivables. In addition to all these, concerns have to necessarily keep cash to pay the manufacturing expenses, etc., and to meet the contingencies.

Permanent and Temporary Working Capital Working Capital in a business is needed because of the operating cycle.

But the need for working capital does not .come to an end after the cycle is completed. Since the operating cycle is a continuous process, there remains a need for a continuous supply of working capital. However, the amount of working capital required is not constant. throughout the year, but keeps fluctuating.

On the basis of this concept, working capital is classified into two types:
(a) Permanent Working Capital: The need for working capital or current assets fluctuates from time to time. However, to carry on day-to-day operations of the business without any obstacles, a certain minimum level of raw- materials, work-in-progress, finished goods and cash must be maintained on a continuous basis. The amount needed to maintain current assets on this minimum level is called permanent or regular working capital. The amount involved as permanent working capital has to be met from long-term sources of finance, e.g., capital, debentures, long-terms loans, etc.

(b) Temporary or Variable Working Capital: Any amount over and above the permanent level of working capital is called temporary, fluctuating, or variable working capital. Due to seasonal changes, the level of business activities higher than normal during some months of the year, and therefore, additional working capital will be required along with the permanent working capital. It is so because during peak season, demand rises and more stock is to be maintained to meet the demand.

Similarly, the amount of debtors increases due to excessive sales. Additional working capital thus needed is known as temporary working capital because once the season is over, the additional demand will be no more.’The need for temporary working capital should be met from short-term sources of finance, e.g. short-terms loans, etc. So that it can be refunded when it is not required.

Both types of working capital are necessary to run the business smoothly. The distinction between permanent and temporary working capital is illustrated in the following diagram:

Diagram: Showing Permanent and Temporary Working Capital.

The above diagram shows that permanent working capital remains the same throughout the year, while temporary working capital is fluctuating in accordance with seasonal demand.

However, in case of an expanding concern, the need for permanent working capital may not be constant and it would be increasing.

Therefore, the permanent working capital line also may not be horizontal and it will go on rising as illustrated in the following diagram:

Diagram: Showing Permanent and Temporary Working Capital in a Growing Concern

Question 5.
Define the term ‘Cost of Capital’. Also, explain the Significance of the cost of capital.
Answer:
The cost of capital of a firm is the minimum rate of return expected by its investors. The capital used by a firm may be in the form of equity shares, preference shares, debts, and retained earnings. The cost of capital is the weighted average cost of these sources of finance used by the firm. The concept of cost of capital occupies a very important role in financial management because investment decisions are based on it. If a firm is not able to achieve its cost of capital the market value of its shares will fall.

Definition:
Cost of capital for a firm may be defined as the cost of obtaining the funds, i.e., the average rate of return that the investors in a firm expect, for investing funds in the firm.

It is also referred to as cut-off rate,-target rate, hurdle rate, the minimum required rate of return, etc.

Some of the important definitions of cost of capital are stated below:

• “The cost of capital is the minimum required rate of earnings or the cut-off rate of capital expenditures.” – Ezra Salomon
• “The cost of capital is the minimum rate of return which a firm requires as a condition for undertaking as an investment.” – Milton H. Spencer
• “Cost of Capital represents a cut-off rate for the allocation of capital to investments of projects. It is the rate of return on a project that will leave unchanged the market price of its securities.” – James C. Van. Horne
• “The Cost of Capital is the rate of return a company must earn on an investment to maintain the value of the company.” – M. J. Fordon
• “A firm’s so-called cost of capital – commonly expressed as an annual percentage figure – is simply that rate of return which its assets must produce in order to justify raising the funds to acquire them.” – W. G. Lawpllen

Thus, on the basis of the above definitions, we can say that cost of capital is the minimum rate of return that a firm, must and, is expected to earn on its investments so as to maintain the market value of its shares.

Significance of the Cost of Capital: The concept of cost of capital is very important in making all the financial decisions of the firm. No financial decision is possible without the use of the cost of capital. Some important uses of cost of ’ capital are:
1. Helpful in Designing the Capital Structure: The concept of cost of capital plays a vital role in designing the capital structure of a company. The capital structure of a company consists of different sources of capital such as equity capital, retained earnings. Preference capital and debt capital. These sources differ from each other in terms of their respective costs. As such a company will have k to design such a capital structure that minimizes the cost of capital. Hence, the calculation of the cost of capital of different sources of capital is very essential to design an optimum capital structure.

2. Helpful in taking Capital Budgeting Decisions Capital budgeting is the process of decision making regarding the investment of funds in long-term projects of the company. The concept of cost of capital is very useful in making capital budgeting decisions $ because the cost of capital is the minimum required rate of return on an investment project. Also, a Finn must not invest in those projects which generate a return less than the cost of capital incurred for its financing.

Net Present Value (NPV) and Internal Rate of Return (IRR) are two important methods used in capital budgeting. Both of these methods are dependent upon the use of the cost of capital. In the NPV method, a project is accepted if its NPV is positive. The project’s NPV is calculated by discounting its cash flows at the cost of capital rate. Under the IRR method, the cost of capital is used as a minimum required rate of return. Hence, the cost of capital serves as a decision criterion for taking capital budgeting decisions.

3. Helpful in Evaluation of Financial Efficiency of Top Management: The concept of cost of capital can be used to evaluate the financial efficiency of top management. Such an evaluation will involve a comparison of the projected overall cost of capital with the actual cost of capital incurred by the management. Lower the actual cost of capital better is the financial performance of the management of the firm.

4. Helpful in Comparative Analysis of Various Sources of Finance: Cost of capital to be raised from various sources goes on changing from time to time. Calculation of cost of capital is helpful in the analysis of the usefulness of various sources of finance. A particular source of finance may be encouraged or discouraged on the basis of its changed cost.

5. Helpful in taking other Financial Decisions: The cost of a capital concept is also useful in making other financial decisions such as dividend policy, rights issue, working capital decisions, and capitalization of profits.

Question 6.
Explain the various factors affecting working capital requirements.
Answer:
Factors affecting working capital requirements:
1. Nature of Business: The basic nature of business influences the amount of working capital required. A trading organization usually needs a lower amount of working capital compared to a manufacturing organization. This is sales can be effected immediately upon the receipt of materials, sometimes even before that. In a manufacturing business, however, raw material needs to, be converted into furnished goods before any sales become possible. Other factors remaining the same, trading business requires less working capital. Similarly, service industries that usually don’t have to maintain inventory require less working capital.

2. Scale of operations: For an organization that operates on a higher scale of operations, the quantum of inventory, debtors that are required is generally high. Such organizations, therefore require a large amount of working capital as compared to the organizations which operate on a lower scale.

3. Business Cycle: Different phases of business cycles affect the requirement of working capita! by a firm. In case of a boom, the sales, as well as production, are likely to be higher, and therefore higher amount of working capital is required. As against this, the requirement for working capital will be lower during the period of depression as the sales as well as production will below.

4. Seasonal factor: Most businesses have some seasonality in their operations. In peak season, because of a higher level of activity, a higher amount of working capital is required. As against this, the level of activity, as well as the requirement for working capital, will be lower during the lean season.

5. Production Cycle: The production cycle is the time span between the receipt of raw materials and their conversion into finished goods. Some businesses have a longer production cycle while some have a shorter one. Duration and the length of the production cycle affect the number of funds required for raw materials and expenses. Consequently working capital requirement is higher in firms with longer processing cycles and lower in firms with shorter processing cycles.

6. Credit Allowed: Different firms allow different credit terms to their customers. These depend upon the level of competition that a firm faces as well as the creditworthiness of its clientele.

A liberal credit policy results in a higher amount of debtors, increasing the requirement of working capital.

7. Credit Availed: Just as a firm allows credit to its customers it also may get credit from its suppliers. To the extent, it avails the credit on its purchases, the working capital requirement is reduced.

8. Operating Efficiency: Firms manage their operations with varying degrees of efficiency. For example, a firm managing its raw materials efficiently may be able to manage with a smaller balance. This is reflected in a higher inventory turnover ratio. Similarly, a better debtors turnover ratio may be achieved reducing the amount tied up in receivable. Better sales effort may reduce the average time for which finished goods inventory is held. Such efficiencies may reduce the level of raw materials, finished goods, and debtors resulting in the lower requirement of working capital.

9. Availability of raw material: If the raw materials and other required materials are available freely and continuously, lower stock levels may suffice. If however, raw materials do not have a record of uninterrupted availability, higher stock levels may be required. In addition, the time lag between the placement of the order and actual receipt of the materials (also called lead time) is also relevant. The higher the lead time, the higher the quantity of material to be stored and the higher is the amount of working capital requirement.

10. Growth Prospects: If the growth potential of concern is perceived to be higher, it will require a higher amount of working capital so that it is able to meet higher production and sales target whenever required.

11. Level of Competition: A higher level of competitiveness may necessitate higher stocks of finished goods to meet urgent orders from customers. This increases the working capital requirement. Competition may also force the firm to extend liberal credit terms.

12. Inflation: With rising prices, higher amounts are required even to maintain a constant volume of production and sales. The working capital requirement of a business thus becomes higher with a higher rate of inflation. It must, however, be noted that an inflation rate of 5%, does not mean that every component of working capital will change by the same percentage. The actual requirement shall depend upon the rates of price change of different components (e.g. raw materials,’ labor cost, finished goods.) as well as their proportion in the total requirement.

Financial Management Important Extra Questions Long Answer Type

Question 1.
Explain the various determinants of the financial needs of a business?
Answer:
Determination of Financial Needs of a Business
or
Assessing Funds Requirements
Answer:
Estimating or determining the financial requirements of the business is one of the main objectives of financial planning. Before raising funds, it is essential that the requirement of funds be correctly estimated. In the absence of correct estimates, the firm may suffer either from inadequate or surplus funds. If the funds are short of its requirements, the firm will not be able to meet its day-to-day expenses and pay the short-term and long-term liabilities on time.

On the other hand, if the funds are in excess of the requirements of the business, they will remain idle and will reduce the profitability of the business. Hence, the estimates should be made in a way that all financial requirements are properly satisfied.

Funds requirements of a business can broadly be classified into two main categories. They are:

1. Fixed Capital Requirements, and
2. Working Capital Requirements.

Assessment of Fixed Capital Requirements: Fixed capital is the capital that is meant for fulfilling the permanent or long-term needs of the business. In the words of Shubin, “Fixed capital is the funds required for the acquisition of those assets that are to be used over and over for a long period.”

Fixed capital is required for acquiring fixed assets. Fixed assets may include the following:

1. Tangible assets such as land, buildings, plant and machinery, furniture, etc.
2. Intangible assets such as goodwill, patents, copyrights, etc.

A certain amount of fixed capital is also required for meeting certain expenditures not leading to the creation of an asset like research expenses, promotional expenditure incurred for the establishment of business, share issue expenses, underwriting commission, etc. The requirement of funds for these expenditures is long-term and hence the funds required in respect thereof are also included under fixed capital.

Every business needs a fair amount of fixed capital to be invested in fixed assets so as to create production or business facilities. For a new business, the fixed capital is needed in the beginning because fixed assets are needed at the time of promoting or establishing the business. For an existing business fixed capital is required for the development and expansion of the business. Hence, it is essential to have an adequate amount of fixed capital in the business.
The assessment of fixed capital requirements for a new business can be made by preparing a list of fixed assets needed by the business.

The list is prepared by the promoters by studying similar units and by taking advice from technical experts. The estimation of cost of land can be made from property dealers, estimation regarding the cost of building can be made with the help of building contractors and the cost of machinery can be ascertained from the suppliers of the machinery. Similarly, the amount to be paid for goodwill, patents, trade-marks, etc. can also be estimated.

Factors Affecting the Estimation of Fixed Capital/Fixed Assets Requirements: Factors that affect the estimation of Fixed Capital or Fixed assets requirements can be studied under two heads
(a) Internal Factors and
(b) External Factors.

(a) Internal Factors:
1. Nature of Business: Certain types of businesses require heavy investment in fixed assets, while others do not. Usually, the manufacturing concerns require more fixed assets than trading concerns. Similarly, public utility undertakings like railway, electricity, water supply, etc. require huge funds to be invested in fixed assets.

2. Size of Business: Larger the size of a concern, the greater will be the requirement of fixed capital. Also, in larger concerns, most of the activities are performed with the help of automatic machines. As such, they require a huge investment in fixed assets.

3. Types of Products: A concern that manufactures simple consumer products such as soap, oil, etc. will need a lesser amount of fixed capital in comparison to a concern that manufactures complicated products such as motorcycles, cars, etc.

4. Activities Undertaken by the Enterprise: A concern that is engaged in the manufacturing of all parts of a product by itself will require a greater amount of fixed capital as compared to a concern that gets most of the parts manufactured from outside and merely assembles them. Similarly, if a concern itself manufactures and markets its products, it will require more amount of fixed capital as compared to a concern that is engaged only in the manufacturing or only in marketing activities.

5. Mode of Acquisition of Fixed Assets: If some of the fixed assets are available on the lease or on hire, a lesser amount of fixed capital will be required. On the contrary, if all the fixed assets are to be purchased on immediate cash payment, a larger amount of fixed capital will be needed.

6. Acquisition of Old Assets: In certain industries, old plant and machinery may be available at sufficiently reduced prices and which can be used ‘satisfactorily. It would reduce the requirement of fixed capital to a great capital to a great extent. But the old plant and machinery should be used in the industries where the technological changes are moderate or slow.

7. Availability of Fixed Assets of Concessional Rate: In some areas, the Government provides land and other equipment at concessional rates to promote balanced industrial growth. In such a case, the requirement of fixed capital is reduced.

(b) External Factors:
1. General Economic Outlook: If the economy is recovering from depression and the level of business activity is expected to rise, the requirement for fixed assets will also rise and hence the need for fixed capital will also rise.

2. Technological Changes: If rapid technological innovations are taking place in an industry, the need for fixed capital will be larger because the old and out-dated machinery will have to be replaced by new ones.

3. Degree of Competition: The degree of Competition also affects the Fixed Capital-requirements. If there is a lot of competition in some industries, the need for fixed capital will be more because if some firms go on adopting the new technology, the others have to follow them.

4. Shift in Consumer Preferences: If the consumer preferences go on changing in some industries, the need for fixed capital will be more because the firm will have to produce new varieties accordingly, which require more investment in fixed assets.

Assessment of Working Capital Requirements: After the assessment of fixed Capital, funds required for working capital are assessed. The term ‘Working Capital’ is used in two ways.

In one sense it denotes the ‘total current assets’ whereas in another sense it is regarded as the excess of current assets over current liabilities. Current assets include cash, receivables (i.e., debtors and bills receivables), stock, etc. The amount required to be invested in current assets differs from one business to another. The amount depends on various factors such as nature and size of the business, duration of the production cycle, rapidity of turnover, credit policy, the quantity of stock, seasonal fluctuations, rate of growth, etc.

Working capital may be fixed or fluctuating. Fixed working capital refers to the minimum amount which would always be invested in raw materials, work-in-progress, finished goods, receivables, and cash balance. This amount is absolutely essential throughout the year on a continuous basis to maintain a desirable level of business activity. The amount required for fixed working capital mainly depends on the duration of the production cycle.

The cycle starts from the purchase of raw material; then the raw material is converted into finished goods by incurring labor and other costs. On sale, these finished goods are converted into debtors and lastly, the firm will again have cash when the debtors pay. The length of the production cycle (i.e., the length of time between the purchase of raw material and receiving cash from debtors) will determine the quantum or requirements of fixed working capital. The longer the cycle, the higher will be the requirements of fixed working capital.

The requirement of working capital over and above the fixed working capital is known as fluctuating working capital. It keeps on fluctuating from time to time according to the change in the level of business activities. For instance, during peak season, due to intensive sales, more funds are blocked in stocks and debtors and thus more amount will be required for fluctuating working capital.

The total amount of working capital can be estimated by estimating the needs of working capital for the following:

1. For maintaining adequate stock
2. For receivables.
3. For paying day-to-day expenses
4. For contingencies

1. For maintaining adequate stock: Every industrial undertaking is required to maintain a minimum stock of raw materials, work in progress, and finished goods. The requirement of the stock is determined by various factors like volume of production, the length of the production cycle, and the period for which the finished goods have to remain in a warehouse before they are sold.

2. For receivables: Finished goods may be sold for cash or on credit. Credit sales take the form of receivables (i.e., debtors and bills receivables). The amount is tied up in receivables until cash is realized from them. The amount tied up in receivables depends upon a number of factors such as quantum of credit sales, credit period allowed, the efficiency of the debt collection system, etc. For example, if a firm changes its credit period from 30 days to 60 days, the amount tied up in debtors will go up, and consequently, the need for working capital will also increase by a similar amount.

3. For paying day-to-day expenses: A firm has to carry some minimum cash balance to make payment for wages, salaries, and other expenses throughout the year. A proper cash balance is also maintained to avail of the cash discounts facilities offered by proper cash balance is also maintained to avail of the cash discounts facilities offered by the suppliers.

4. For contingencies: A minimum cash balance is also maintained for meeting unseen contingencies so that the business successfully sails through the period of crisis.

Thus, the overall financial needs of a business can be determined, by assessing the needs for fixed capital and working capital separately and then by adding the two.

Question 2.
Define the term ‘Over-Capitalisation’ and ‘Under Capitalisation’ and their causes?
Answer:
Over Capitalisation: Quiet often, the term ‘Over-Capitalisation’ is misunderstood to mean the excess of capital. But in actual practice, over-capitalized concerns have been found short of funds.

In fact, over-capitalization refers to that state of affairs where a company earns less than what should have earned at a fair rate of return on the capital invested in it. In other words, if a company is continuously unable to earn a fair rate of return on its capital, it is termed an over-capitalized company.

In the words of Bonneville Dewey, ” When a business is unable to earn a fair rate of return on its outstanding securities, it is over¬capitalised.”

According to Gerstenberg, “A corporation is over-capitalized when its earnings are not large enough to yield a fair return on the number of stocks and bonds that have been issued or when the amount of securities outstanding exceeds the current value of assets.”

The same view has been expressed by Harold Gilbert in these words, “When a company has consistently been unable to earn the prevailing rate of return o.n its outstanding securities (considering the earning of similar companies in the same industry and the degree of risk involved) it is said to be over-capitalized.”

It is clear from the above definitions that the situation of over¬capitalisation arises due to a fall in the earning capacity of the business. On account of this, the earnings will not be sufficient to give a reasonable return on capital employed in it. For example, a company is earning a profit of Rs. 8,00,000 on a total capital investment of Rs. 80,0, 000. In case the normal, rate of return prevailing in the market is 10%, this company will be said to be fairly capitalized. However, if it earns only Rs. 2,20,000 while the normal rate is 10%, the company will be said to be over-capitalized because it will be able to give a return of only 6% on the total capital employed.

In order to ascertain whether a company is earning a fair return or not, the rate of return earned by the company should be compared with similar firms in that industry. If the company’s rate of return is t .substantially less than the average rate earned by other firms, will indicate that the company is unable to earn a fair return on the capital 1 employed in it. It may also be noteworthy that a company will be said to be over-capitalized only when it is continuously unable to earn fair income over a long period of time. If its earning is reduced temporarily, owing to the occurrence of abnormal events like strikes, lockouts, etc. the company will not be called over-capitalized.

Causes of Over-Capitalisation:
Following are some of the important causes of over-capitalization:-
1. Over-Issue of Capital: If a company raises more capital than it can profitably use, there will be a large number of idle funds will the company. Because of idle funds, the earning capacity of the company will be reduced. This leads – to the situation of over-capitalization because the company will have to pay dividends on idle capital too. Hence, the rate of dividend will fall which in turn leads to a fall in the market price of its shares.

2. Promotion of the Company with Inflated Assets: A company will fall prey to over-capitalization if it is promoted with assets purchased at excessive prices, the reason is that such prices of the assets do not fear any relation to their earning capacity. Such a situation arises particularly when a partnership firm or private company is converted into a public company and in that process, their assets may be transferred to the public company at price higher than their real values. Sometimes, the promoters also transfer their property to the new company at inflated prices.

3. Promotion or Expansion of the Company during Boom Period: If a company is formed or expanded during the boom period, it; may becomes a victim of over-capitalization. The reason is that the price paid for assets will be quite high. When the boom disappears the real value of such assets will decline to a great extent whereas they will be shown in the books at their original values. Such a company is over-capitalized because its earning will fall due to depression but the assets and capital will be shown in the books in previous figures.

4. High Promotion Expenses: A certain degree of over-capitalization may be caused due to the. fact that the promoters have incurred heavy expenses on the promotion. of the company, a huge amount may have been spent on issue and underwriting of shares and the promoters may have taken a fabulous. remuneration for the services rendered by them. A major part of the earnings of the company will be utilized to write off these expenses and consequently, the company will not be able to pay fair dividends on its shares.

5. Over-estimation of Earnings at the Time of promotion: In case of a new concern,-the amount of capitalization is determined on the basis of estimates of future earnings. However, if it is found that the actual earning is less than the estimated earning, it will lead to a situation of over-capitalization. For example, if a company’s annual earnings were estimated at Rs, 50,000 and its current rate of return (or N capitalization rate) is 10% its, capitalization will be fixed at Rs. 5,00,000. Subsequently, it was found that the company actually earned (Rs. 40,000. On this basis, the company’s capitalization should have been: fixed at Rs. 4,00,000. Thus, the company will be over-capitalized by 4 Rs. 1,00,000.

6. Under-estimation of Rate of Return at the Time of Promotion: A concern may have correctly estimated the number of its earnings, but it may have under-estimated its rate of return (i.e., capitalization, rate). For example, a company’s annual earnings were estimated at ‘ Rs. 50,000 and the rate of return were fixed at 10%. By applying this rate the company’s capitalization was worked out at Rs. 5,00,000. Subsequently, it was found that the actual rate of return was 12.5%, and hence the amount of capitalization should have been fixed at Rs. i.e., Rs. 50,000 × 100. 12.5 Obviously, there is over-capitalization to the extent of Rs.1,00,000.

7. Shortage of Capital: Sometimes, the shortage of capital may also lead to over-capitalization. It may happen when the promoters underestimate the requirements of capital and raise less capital in relation to the needs of the business. In such a case the company will be forced to borrow a large sum of money at an unreasonably high rate of interest. A major part of the earnings will be absorbed by the amount of interest, leaving little for the shareholders. This will bring down the value of shares leading to over-capitalization.

8. Inadequate Depreciation: If a company does not make sufficient provisions for depreciation and replacement of assets, it will find after some time that the earning capacity of the assets is diminished leading to a fall in its earnings. This is yet another case of over-capitalization.

Under-capitalization: The term ‘under-capitalization’ does not mean a shortage or inadequacy of capital. The term is just reverse to over-capitalization. In the words of Greenberg:

“A corporation may be under-capitalized when the rate of profits, it is making on total Capital, is exceptionally high in relation to the return enjoyed by similarly situated companies in the same industry, or when it has too little capital with which to conduct its business.”

In simple words, under-capitalization is a state of affairs when the capital or resources of the company are being utilized more efficiently. As a result, the company succeeds in continuously earning an abnormally high rate of return on the capital employed in it. Such a company declares a high rate of dividend in comparison to the prevailing rate and the market value of its shares exceeds their book value. Thus under-capitalization refers to the sound financial position and good management of the company.

Causes of Under-Capitalisation:
The following are the important causes of under-capitalization:
1. Under-Estimation of Capital Requirements: At the time of promotion, the promoters may under-estimate the capital requirements of the company. This results in a situation of under-capitalization at later stages when more capital is required.

2. Under-Estimation of Earnings: Sometimes at the time of promotion, the future earnings of the company are under-estimated and the company is capitalized accordingly. If afterward it is found that the actual earnings are far in excess of the estimates, the company may find itself in a situation of under-capitalization.

3. Over-Estimation of Rate of Return at the Time of Promotion: Sometimes a concern estimates its income correctly but it over-estimates its rate of return (i.e„ capitalization rate). For example if a company’s earnings were estimated at Rs. 60,000 and the rate of earnings were fixed at 15%. By applying this rate the capitalization was fixed at‘Rs. 4,00,000 (i.e., Rs. 60,000 × \(\frac{100}{15}\)). Subsequently, it was ascertained that the actual rate was 10% and hence the amount of capitalization should have been Rs, 6,00,000 (i.e., Rs. 60,000 × \(\frac{100}{10}\)). Thus, the company is under-capitalized by Rs. 2,00,000.

4. Promotion of Company During Deflation: Companies that are floated under recessionary conditions often experience under-capitalization after the recession is over. This is because of two reasons. Firstly, during recession assets are purchased at a price that is must lower in comparison to their earning capacity. Secondly, companies established during a recession are capitalized at a low figure anticipating low earnings but when the recession is over earnings increase and the company becomes under-capitalized.

5. Conservative Dividend Policy: Certain companies follow a policy of declaring low dividends and plowing back a major part of their earnings. They build up large funds for replacement, renovation, and expansion. The result of such a policy is reflected in high earnings which is a situation of under-capitalization.

6. High Level of Efficiency: In a company where the management is very efficient, the company may operate on a high efficiency even with a meager amount of capital. Over a period, earning the position of the company will improve and it will become under-capitalized.