NCERT Exemplar Solutions for Class 10 Science Chapter 16 Management of Natural Resources

NCERT Exemplar Solutions for Class 10 Science Chapter 16 Management of Natural Resources

These Solutions are part of NCERT Exemplar Solutions for Class 10 Science. Here we have given NCERT Exemplar Solutions for Class 10 Science Chapter 16 Management of Natural Resources

NCERT Exemplar Solutions for Class 10 Science Chapter 16 Short Answer Questions

Question 1.
Prepare a list of items that you use daily in the school. Identify from the list five such items that can be recycled.
Answer:
Items. Rexin bag, steel lunch box, steel spoon, steel compass, steel dividers, paper, plastic box, pen, pencil, blade, eraser, handkerchief.
Recycleable Items. Steel lunch box, steel spoon, steel compass, steel dividers, blade, paper, plastic box.

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Question 2.
List the advantages associated with water harvesting at the community level. (CCE 2012)
Answer:
Water harvesting at the community level is capturing, collection and storage of rain water and surface run off for filling either small water bodies or recharging ground water. This is carried out through water shed management, check dams, earthen dams, roof top harvesting and filter wells in flood drains.
Benefits:

  1. It ensures water availability in non-rainy season,
  2. It reduces the chances of flooding during rainy season,
  3. Ground water level does not fall as it is regularly recharged,
  4. Ground water recharge is the best form of water harvesting as the water is filtered and free from contaminations. It also does not evaporate,
  5. Water becomes available for drinking as well as irrigation.

Question 3.
In a village in Karnataka people started cultivating crops all around a lake which was always filled with water. They added fertilizers to their field in order to enhance the yield. Soon they discovered that the water body was completely covered with green floating plants and fishes started dying in large numbers.
Analyse the situation and give reasons for excessive growth of plants and death of the fish in the lake.
Answer:
Fertilizer rich run off from fields must have passed into the lake. It caused nutrient enrichment of lake water. The result is excessive growth of algae and other aquatic plants which float on the water surface and produce water bloom. Old dead plants produce a lot of organic matter. The submerged plants are also killed due to shading. BOD of water increases. As more and more oxygen is consumed by decomposers little is left for respiration of aquatic animals. Therefore, fish begin to die. The phenomenon of nutrient enrichment of water body that causes formation of water bloom and subsequent killing of aquatic life is called eutrophication.

Question 4.
What measures would you take to conserve electricity in your house ? (CCE 2012)
Answer:

  1. Judicious use of electricity by switching off lights and electrical appliances not required,
  2. Replacement of incandescent bulbs with fluorescent, compact fluorescent ones and LED bulbs.
  3. Replacement of electricity or gas operated geysers with solar water heaters,
  4. Replacement of electricity generating sets with solar light,
  5. Having more natural light and ventilation with design supporting warming during winters and cooling during summer.

Question 5.
Although coal and petroleum are produced by degradation of biomass, yet we need to conserve them. Why ? (CCE 2012)
Answer:
Coal and petroleum have been produced from large amounts of biomass entrapped inside the earth under high temperature, pressure and anaerobic conditions. Such a situation develops only rarely like big upheavals on earth. At present no more coal or petroleum is being formed. All that is available has been formed millions of years ago. Being rich source of energy, coal and petroleum are being consumed in ever increasing amount in industry, transport, kitchens, etc. If the trend continues, soon they will be exhausted. Therefore, they must be conserved by developing more efficient machines, hybrid engines and using hydrogen as a fuel.

Question 6.
Suggest a few measures for controlling carbon dioxide levels in the atmosphere.
Answer:

  1. Increasing Vegetation Cover. It will increase utilisation of atmospheric CO2 in photosynthesis.
  2. Seeding of Oceans With Phytoplankton. Increased photosynthetic activity of oceans will result in decreasing CO2 concentration.
  3. Carbonation. CO2 released during combustion should not be allowed to pass into atmosphere. Instead, it can be changed into carbonates.
  4. Alternate Sources of Energy. Instead of fossil fuels, hydrogen fuel and solar energy should be used.
  5. Burning of Litter. Litter and crop residue should not be burnt but instead converted into manure.

Question 7.
(a) Locate and name the water reservoirs in figures (i) and (ii).
(b) Which has advantage over the other and why ?
NCERT Exemplar Solutions for Class 10 Science Chapter 16 Management of Natural Resources image - 1
Answer:
(a) Water reservoir in figure (i) is pond while it is underground water body (ground water) in figure (ii).
(b) Ground water is more advantageous than pond water.
For Benefits: 

  1. Prevents flooding,
  2. Checks soil erosion.
  3. Retains water underground and prevents drought,
  4. Increases life of downstream reservoirs and dams,
  5. Higher biomass production and income of water shed community,
  6. Maintenance of ecological balance.

NCERT Exemplar Solutions for Class 10 Science Chapter 16 Long Answer Questions

Question 8.
In the context of conservation of natural resources, explain the terms reduce, recycle and reuse. From among the materials that we use in daily life, identify two materials for each category.
Answer:
Three Rs — reduce, recycle and reuse.

  1. Reduce: It is to reduce consumption by preventing wastage.
    1. Switching off unnecessary lights, fans and other electrical appliances,
    2. Repair of leaky taps.
    3. Reducing food wastage,
    4. Walking down to nearby market instead of using vehicle.
  2. Recycle: Separation of recyclable wastes from non-recyclable wastes. The former are taken by rag pickers for sending them to industries involved in recycling, e.g., paper, plastic, metal, glass.
  3. Reuse: Carry bags, packing material, plastic containers and other reusable articles should not be thrown away if the same are uncontaminated. For example, plastic bottles and jars containing various food items brought from market can be washed and used for storing things in the kitchen.

Question 9.
Prepare a list of five activities that you perform daily in which natural resources can be conserved or energy utilisation can be minimised.
Answer:

  1. Judicious use of electricity by switching off lights and electrical appliances not required,
  2. Replacement of incandescent bulbs with fluorescent, compact fluorescent ones and LED bulbs.
  3. Replacement of electricity or gas operated geysers with solar water heaters,
  4. Replacement of electricity generating sets with solar light,
  5. Having more natural light and ventilation with design supporting warming during winters and cooling during summer,
  6. Reducing wastage of water, food and other articles.
  7. Separation of recyclable waste from non-cyclable waste prior to disposal.
  8. Increasing reuse of containers,
  9. Using cloth bags instead of polythene, plastic or paper bags.

Question 10.
Is water conservation necessary ? Give reasons.
Answer:

  1. Distribution of fresh water is highly uneven. Large tracts are deficient in rain as well as ground water,
  2. At most places more water is withdrawn from reservoir and underground source than their recharging
  3. Requirement in urban and industrial areas is nearly always higher than the availability,
  4. Further demand for water is rising by 4 – 8% annually in all fields, whether agriculture, industry or domestic use.

Therefore, water conservation is necessary. Wastage of the resource should be prevented. Waste water should be recycled. Water harvesting involving recharging of ground water should be practised.

Question 11.
Suggest a few useful ways of utilising waste water.
Answer:
Waste or used water can also become a resource.

  1. Treated municipal water can be poured in irrigation channels for supply to crop fields,
  2. Treated waste water can be used in urban areas for watering gardens, lawns and washing vehicles,
  3. Industries can treat their waste water and recycle the same,
  4. Waste water passed into ponds recharges the ground water,
  5. Sewage sludge, separated from waste water is a source of manure, compost and biogas.

Question 12.
What is the importance of forests as a resource ?
Answer:
Economic Reasons:

  1. Food: Tribals obtain most of their food requirements from the forests, e.g., fruits, tubers, fleshy roots, leaves.
  2. Nuts: Pine Nut (Chilgoza), Almond, Walnut and Cashewnut are obtained from forests trees.
  3. Spices: Cardamom, Cinnamon, Nutmeg and Cloves are spices obtained from forest plants.
  4. Commercial Products: A number of forest products are of commercial importance, g., rubber, resin, tannins, tendu, lac, cork, camphor, essential oils, soap pod and drugs.
  5. Fuel Wood: Nearly two billion persons depend upon forests for fuel wood.
  6. Timber: Wood for the manufacture of furniture, household fitments and several other articles mostly comes from forests. Bamboo is called poorman’s timber as it is used in thatching huts, preparing baskets and a number of other articles including furniture.
  7. Paper: It is prepared from cellulose rich plants like bamboos, Boswellia, Eucalyptus, grasses and several

Protective Functions:                                                                                  i

  1. Forests provide shelter to wild animals. Over 40 million tribals and villagers live in forests.
  2. Plant roots hold the soil firmly. Vegetation protects the soil from action of wind and water. Forests, therefore, protect the soil from erosion and landslides.
  3. Pollution. Forests reduce atmospheric pollution by absorbing gases, collecting suspended particles and reducing noise.

Regulative Functions:

  1. Absorption and Retention of Water. Forests reduce run off, hold water like a sponge and allow slow percolation to form perennial springs and rivulets.
  2. Forests increase atmospheric humidity, increase frequency of rainfall and moderate temperature.
  3. Atmospheric Gases. Forests absorb large quantity^ of C02 from the atmosphere, reducing the threat of global warming. They also release a lot of oxygen.

Question 13.
Why are Arabari forests of Bengal known to be good example of conserved forests.
Answer:
Regeneration of Sal Forests — An Example of People’s Participation in the Management of Forests Despite best efforts, the West Bengal Forest Department could not revive the degraded Sal forests of Southwestern districts of the state. Excessive surveillance and policing of the degraded forests not only alienated the people but also resulted in frequent clashes between villagers and forest officials. This also fueled the militant peasant movement led by Naxalites. Realising the failure, the forest department revised its strategy in 1972. It allowed forest officer A.K. Banerjee of Arabari forest range of Midnapore to involve villagers in regeneration of 1272 hectares of badly degraded Sal forest. Banerjee provided employment to villagers in silviculture (cultivation of trees) and harvesting, 25% of final harvest and allowed collection of fuel wood as well as fodder at nominal fee. By 1983, the Arabari forest had been revived and was then valued at 12-5 crores.

Hope given NCERT Exemplar Solutions for Class 10 Science Chapter 16 Management of Natural Resources are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

Value Based Questions in Science for Class 10 Chapter 16 Management of Natural Resources

Value Based Questions in Science for Class 10 Chapter 16 Management of Natural Resources

These Solutions are part of Value Based Questions in Science for Class 10. Here we have given Value Based Questions in Science for Class 10 Chapter 16 Management of Natural Resources

Question 1.
Your father has a car. He can also afford to hire a driver. Even then he sends you in school bus. What is the rationale behind it ?
Answer:
It is saving on natural resources for which your father insists on your going to school in the school bus. The bus has to make trip to school. There will be no extra gasoline consumption if you go to school in the bus. Going by car will consume gasoline. If every student who can afford goes in a car, the consumption of gasoline will go up several times. It is because of this reason that many offices maintain cabs for bringing the employees to the work place. It is just similar to our campaign to save electricity (by putting off light and gadgets not in use) or water (by turning off the tap when water is not required).

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Question 2.
CFL is quite costly as compared to incandescent electric bulb. Even then we read that incandescent bulbs should be replaced by CFLs. Why so ?
Answer:
CFL or compact fluorescent lamp consumes one fifth of energy as compared to incandescent bulb. It also produces less heat and is therefore, environmental friendly. The extra money spent on purchasing a CFL will be recovered in the form of lesser energy bill for the consumer. Use of CFLs will help in less consumption of the resource resulting in its greater availability.

Question 3.
What is the social impact of technique developed by Rajinder Singh in Rajasthan ?
Answer:
Rajinder Singh, popularly known as “Water Man of Rajasthan” developed the technique of underground dams for storing run off and rain water. They were connected to surface water tanks as well as crop fields by means of underground channels. The stored water is used for irrigating crop fields throughout the year in areas where water availability is scarce even for drinking.

Question 4.
Your school keeps dust/garbage bins at many places outside the class rooms where the students and the teachers can dump their waste food, waste paper, used pens, pencil shavings, plastic bags, aluminium foils, empty mineral water bottles, etc. The garbage bins are emptied by the school sweeper in larger container of municipal committee for taking away to dumping ground. What improvement would you suggest ?
Answer:
Instead of common garbage bin, I will suggest keeping of two bins, green bin for easily biodegradable articles like waste food, and blue bin for slow decaying and nonbiodegradable articles. The green bins should not be emptied in the container of municipal committee but in a pit inside the school campus for preparing manure for the plants. The blue bins could be emptied in the municipal committee container.
While discussing about coal and petroleum, a teacher told the students about PCRA’s (Petroleum Conserva¬tion Research Association) guidelines to save the fossil fuels while driving vehicles. Deepa was going to her school with her mother who was driving car. At the traffic signal, when the light was red, Deepa suggested her mother to switch off the engine.

Question 5.
After reading the above passage, answer the following questions :
(a) Fossil fuels are natural reserves, then why we need to conseve them ?
(b) List any two ways of saving the fossil fuels
(c) State two values exhibited by Deepa. (CBSE Foreign 2016)
Answer:
(a) Fossil fuels take millions of years for their formation. Their present stock is limited and hence exhaustible. They should be conserved to provide for their availability for future generations.
(b)

  1. Using public transport
  2. Walking short distances.
  3. Use of fuel efficient technology in vehicles.

(c) Deepa exhibited concern for

  1. Conservation of natural resource,
  2. Reduction in environmental pollution
  3. Assertion for global cause.

Question 6.
The activities of man had adverse effects on all forms of living organisms in the biosphere. Unlimited exploi¬tation of nature by man disturbed the delicate ecological balance between the living and nonliving compo¬nents of the biosphere. The unfavourable conditions created by man himself threatened the survival not only of himself but also of the entire living organisms on the mother earth. One of your classmates is an active member of “Eco Club” of your school which is creating environmental awareness amongst the school students, spreading the same in the society and also working hard for preventing ènvironmental degradation of the surroundings.
(a) Why is it necessary to conserve our environment ?
(b) State the importance of green and blue dust bins in the safe disposal of house hold waste.
(c) List two values exhibited by your classmate who is an active member of Eco Club of your school.  (CBSE A.I. 2016)
Answer:
(a) Conservation of Environment:

  1. Protection of air, soil and biota from pollutants,
  2. Maintenance of ecological balance,

(b) Importance of Green Blue Dust Bins. Green dust bins are meant for putting in biodegradable wastes while blue dust bins are used for non-biodegradable wastes. Segregation of the two types of wastes and putting them in separate dust bins helps in quicker disposal of wastes,
(c) Values Shown by Classmate:

  1. Concern for cleanliness of the surroundings.
  2. Quicker and proper disposal of wastes.
  3. Concern for environment.
  4. Civic sense.

Hope given Value Based Questions in Science for Class 10 Chapter 16 Management of Natural Resources are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

HOTS Questions for Class 10 Science Chapter 16 Management of Natural Resources

HOTS Questions for Class 10 Science Chapter 16 Management of Natural Resources

These Solutions are part of HOTS Questions for Class 10 Science. Here we have given HOTS Questions for Class 10 Science Chapter 16 Management of Natural Resources

Question 1.
What does the figure depict ? Identify A, B and C.
Answer:
Caption: Khadin system of water harvesting.
A – Catchment area
B – Khadin (cropped area)
C – Khadin bund
HOTS Questions for Class 10 Science Chapter 16 Management of Natural Resources image - 1

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Question 2.
Why is forest called biodiversity hotspot ?
Answer:
A biodiversity hotspot is an area having a large number of endemic species which are being threatened with extinction. Because of long exploitation of forest resources and pressure from industrialists, the natural biota is being replaced by commercially required trees.

Question 3.
What is Kattas ?
Answer:
It is a water storage system of Karnataka that involves raising an embankment over a draining line.

Question 4.
What is production plantation ?
Answer:
It is growing of commercially important plants over separate piece of land, generally a wasteland.

Question 5.
With the help of an example show that reuse strategy is better than recycling. (CBSE A.I. 2010, CCE 2011)
Answer:
Reuse is better than recycling as

  1. There is no need to send the used article to recycling unit,
  2. There is no consumption of energy as required for recycling.
  3. There is no need to remarket the produce. Instead of throwing away the used one and obtaining a new one after its recycling, a container or bottle can be reused several times, of course, each time after cleaning the same. This will save a lot of money and energy.

Hope given HOTS Questions for Class 10 Science Chapter 16 Management of Natural Resources are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

Value Based Questions in Science for Class 10 Chapter 12 Electricity

Value Based Questions in Science for Class 10 Chapter 12 Electricity

These Solutions are part of Value Based Questions in Science for Class 10. Here we have given Value Based Questions in Science for Class 10 Chapter 12 Electricity

Question 1.
In the house of Ram, there are 20 incandescent bulbs each of 100 W, three geysers each of 2000 W and 20 tubes each of 40 W. All these appliances work for 5 hours in a day. Every month, he pays heavy amount as electricity bill. His son Sham studying in X standard asked his father to replace all incandescent bulbs with CFL bulb each of 40 W to save electricity.

  1. How much units of electricity are saved per month (30 days) by replacing incandescent bulbs with CFL ?
  2. What values are shown by Sham ?

Answer:

  1. Electric energy consumed by 20 incandescent bulbs in 30 days = P x t = 20 x 100 x 5 x 30
    = 300000 Wh = 300 kWh
    = 300 units
    Electric energy consumed by 20 CFL bulbs = 23 x 40 x 5 x 30 = 120000 Wh
    = 120 kWh =120 units
    Units of electricity saved = 300 – 120 = 180 units.
  2. Sham helped his father to pay less electricity bill. He also believes that saving energy contributes for the development of our nation.

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Question 2.
Electricity plays an important role in the development of a country. Ram, a student of class X was studying in the library after school hours. When he left the library, he found that electric fans of all rooms were ‘ON’ although there was no one in the class rooms. He immediately switched ‘OFF’ all the fans and reported the matter to Principal of the school.

  1. Comment on the attitude of Ram.
  2. Why, Ram reported the matter to the Principal ?

Answer:

  1. Ram knows the importance of electricity. He believes that loss of electricity is the loss of school as well as the loss of nation. He is against the misuse of national resources.
  2. He reported the matter to the Principal so that the Principal may ask the peon to ensure that such incident should not occur in future.

Question 3.
A welder was asked by Mr. Sumit to weld an iron grill in his house. He started using electricity by connecting the wires of welding set directly with the transmission wires and not through the energy meter. Sumit’s neighbour objected the action of welder but Sumit sided with the welder. However, the son of Sumit appreciated the neighbour.

  1. Why was the action of welder objected by Sumit’s neighbour ?
  2. Why, Sumit supported the action of the welder ?
  3. Why, Sumit s son appreciated the action of his neighbour ?
  4. Write the commercial unit of electrical energy.

Answer:

  1. It is a crime to steal electrical energy and no honest person can support it.
  2. Sumit thought the welder was doing a favour to him.
  3. Sumit’s son knows that welder is doing wrong.
  4. Kilowatt hour (kWh).

Hope given Value Based Questions in Science for Class 10 Chapter 12 Electricity are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

NCERT Exemplar Solutions for Class 10 Science Chapter 15 Our Environment

NCERT Exemplar Solutions for Class 10 Science Chapter 15 Our Environment

These Solutions are part of NCERT Exemplar Solutions for Class 10 Science. Here we have given NCERT Exemplar Solutions for Class 10 Science Chapter 15 Our Environment

NCERT Exemplar Solutions for Class 10 Science Chapter 15 Short Answer Questions

Question 1.
Why is improper disposal of wastes a curse to environment ?
Answer:
An improper disposal of wastes means addition of pollutants into environment —air, water, soil. They will harm living beings, human assets and human beings. For example, passage of sewage into water body will cause eutrophication, stink, development of sludge, killing of animals and source of water borne pathogens.

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Question 2.
Write the common food chain of a pond ecosystem.
Answer:
NCERT Exemplar Solutions for Class 10 Science Chapter 15 Our Environment image - 1
Question 3.
What are the advantages of cloth bags over plastic bags during shopping ?
Answer:
Advantages of Cloth Bags

  1. Cloth bags are stronger and more durable as compared to plastic bags.
  2. They are washable.
  3. They are reused time and again.
  4. Cloth bags do not pollute environment.
  5. They are made of biodegradable material which can also be recycled.

Question 4.
Why are crop fields known as artificial ecosystems ?
Answer:
Crop fields are known as artificial ecosystems because they are raised, maintained, nourished and reaped by human beings.

Question 5.
Differentiate between biodegradable and non-biodegradable substances. Give examples.
Answer:

Biodegradable Wastes

Non-biodegradable Wastes

1. Origin. They are biological in origin. They are commonly man-made.
2. Degradability. The wastes are degraded by microorganisms. They are not degraded by microorganisms.
3. Accumulation. They do not accumulate in nature. They pile up and accumulate in nature.
4. Biomagnification. The biodegradable wastes do not show biomagnification. The soluble non-degradable wastes enter food chains and undergo biomagnification.
5. Resource. The wastes can be converted into resource. Some wastes can be recycled.
Examples. Garbage, livestock wastes, sewage. Examples. Plastic, polythene, glass, nickel, cadmium, several pesticides.

Question 6.
Suggest one word for each of the following statements/definitions.
(a) The physical and biological world where we live in.
(b) Each level of food chain where transfer of energy takes place.
(c) The physical factors like temperature, rainfall, wind and soil of an ecosystem.
(d) Organisms which depend on the producers either directly or indirectly for food.
Answer:
(a) Biosphere (also environment)
(b) Trophic level.
(c) Abiotic factors.
(d) Consumers (also heterotrophs)

Question 7.
Explain the role of decomposers in the environment. (CCE 2011)
Answer:
Decomposers are saprophytes which feed on organic remains by a process of external digestion and absorption of solubilised materials, e.g., many bacteria, fungi. In the process they perform the following functions :

  1. Cleansing the earth of organic remains and continuously creating space for newer generations of organisms.
  2. Release of minerals from organic remains. The phenomenon is called mineralisation. The released minerals become available to plants for utilization in synthesis of new organic matter. Decomposers, therefore, take part in biogeochemical recycling.

Question 8.
Select the mismatched pair in the following and correct it.
(a) Biomagnification: Accumulation of chemicals at the successive trophic levels of a food chain.
(b) Ecosystem: Biotic component of environment.
(c) Aquarium: A man-made ecosystem.
(d) Parasites: Organisms which obtain food from other living organisms.
Answer:
(b) Ecosystem: It is an ecological system consisting of a distinct biotic community and the physical environment (consisting of a number of abiotic factors) both interacting and exchanging materials between them.

Question 9.
We do not clean ponds or lakes but an aquarium needs to be cleaned. Why ?
Answer:
An aquarium is an artificial system which is also incomplete due to absence of producers, food chains and decomposers. There is no recycling and self cleaning. However, a pond or a lake is a self sustained, natural and complete ecosystem where there is perfect recycling of nutrients.

NCERT Exemplar Solutions for Class 10 Science Chapter 15 Long Answer Questions

Question 10.
Indicate the flow of energy in an ecosystem. Why is it undirectional ? Justify. (CCE 2014)
Answer:
An ecosystem does not have its own source of energy. It receives the same from sun. Green plants or producers trap the solar energy and change it into chemical form during synthesis of food. Herbivores obtain energy from the food they take. A lot of energy dissipates during transfer and utilization of food energy by herbivores (10% law). From herbivores the food energy passes to primary carnivores. However, only about 10% of herbivore energy is passed into body mass of primary carnivores.
The rest is dissipated. From primary carnivores the energy passes into secondary carnivores (10%), etc. It is ultimately lost as heat.
NCERT Exemplar Solutions for Class 10 Science Chapter 15 Our Environment image - 2
Since energy available decreases at every tophic level, very little of it is available at higher trophic levels. There is dissipation of energy at every step of its transfer and transformation. Hence it cannot flow in the reverse direction i.e., energy flow is unidirectional from sun to plants, plants to animals, animals to animals, organic remains to decomposers and dissipation as heat.

Question 11.
What are decomposers ? What will be the consequences of their absence in an ecosystem ?
Answer:
Definition: Decomposers or microconsumers are saprophytes which obtain their nourishment from organic remains by secreting digestive enzymes over the latter and absorbing the solubilised substances.
Absence of Decomposers:

  1. Organic remains will pile up leaving no space for new living beings,
  2. Biogeochemical cycling will stop so that raw materials will not be available to plants for manufacture of more food,
  3. In the absence of food, all living beings will die of starvation.

Question 12.
Suggest any four activities in daily life which are ecofriendly.
Answer:

  1. Use of cloth bags instead of polythene or plastic bags.
  2. Separation of biodegradable and non-biodegradable in green and blue coloured bins.
  3. Use of compact fluorescent lamps instead of incandescent lamps.
  4. Harvesting of rain water and preventing wastage of resources.

Question 13.
Give two differences between food chain and food web.
Answer:

Food Chain

Food Web

1. Units. It consists of a single unit of food relations. It is a complex formed by several units of food relations.
2. Sequence. It is a straight sequence of organisms. It is a network of many linkages among the connected food chains.
3. Populations. It has a maximum of 4-6 populations of different species. A food web consists of numerous populations of different species.
4. Food. Only one type of organism is used as food by a particular type of organism. An organism can use two to several types of organisms as food.
5. Disturbance. A disturbance in food chain is difficult to overcome. A disturbance is overcome after some time.
6. Endangered Species. It does not help in restoring population of endangered species. Rather it may decline further. A food web helps in increasing population of endangered species.

Question 14.
Name the wastes which are generated in your house daily. What measures would you take for their disposal ?
Answer:
Wastes :

  1. Vegetable and fruit peels and rind, stale food, food leftovers, used tea leaves.
  2. Milk pouches, polythene bags, empty cartons.
  3. Waste paper (newspaper, bags, envelopes), packing paper, empty bottles, torn cloth pieces, etc.
  4. Dust and other sweepings.

Disposal :

  1. Separation into biodegradable and non-biodegradable, recyclable and non-recyclable wastes.
  2. Recyclable wastes (waste paper, cloth, polythene or plastic bags, cartons, bottles, cans, etc.) can be given to rag pickers for recycling.
  3. Preparation of compost or vetmicompost from kitchen wastes for home garden (kitchen garden).
  4. In the absence of kitchen garden, the household garbage and other wastes can be given to waste collectors for disposal.

Question 15.
Suggest suitable mechanisms for waste management in fertilizer industries.
Answer:
Fertilizer industries produce mainly two types of wastes (a) Gaseous (b) Effluents. Additionally they may release heat and fuel waste if coal is being used as a source of energy.

  1. Gaseous Wastes: They are passed through wet scrubbers to dissolve the pollutant gases.
  2. Effluents: The effluents of the industry are tested for chemicals present in them. The same can be retrieved and made available to the market. Hot effluents are cooled. Acidic or alkaline nature can be corrected. Heavy metals and toxins can be separated. Only treated and harmless effluents are allowed to be discharged into surrounding environment.

Question 16.
What are the by products of fertilizer industries ? How do they affect the environment.
Answer:
The most common by product of fertilizer industries are axides of nitrogen and sulphur. They pass into atmosphere and spread to all nearby places. The gases have a corrosive effect on several items besides being harmful to living beings. They also give rise to acid rain. Acid rain is highly destructive to forests, crops and aquatic biota.

Question 17.
Explain some harmful effects of agricultural practices on the environment.
Answer:

  1. Soil: Fertilizer added to soil not only changes the chemistry of the soil but also kills many useful microbes.
  2. Ground Water: A part of fertilizer always leaches down into soil and reaches ground water. It raises the salt content of ground water.
  3. Eutrophication: Run-off from fields sprayed with fertilizer reaches water bodies. It results in their eutrophication.
  4. Pesticides: Pesticides sprayed over crops reach water bodies killing the biota. Persistent pesticides undergo biomagnification and prove highly harmful to higher organisms.
  5. Ground Water: Continued use of ground water in agriculture has resulted in lowering of water table at most of the places.
  6. Irrigation: It causes water-logging and salination of soils.
  7. Genetic Erosion: Use of only selected high yielding varieties has resulted in genetic erosion of the crop plants.
  8. Damage to Nature: Natural ecosystems and habitats have been damaged during clearing land for agriculture.

Hope given NCERT Exemplar Solutions for Class 10 Science Chapter 15 Our Environment are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

Value Based Questions in Science for Class 10 Chapter 7 Control and Coordination

Value Based Questions in Science for Class 10 Chapter 7 Control and Coordination

These Solutions are part of Value Based Questions in Science for Class 10. Here we have given Value Based Questions in Science for Class 10 Chapter 7 Control and Coordination

Question 1.
How do tendrils reach the support when they do not have any sensory structures.
Answer:
Tendrils do not have any sensory structures but still they are able to find their support just as we grope in the dark for finding the switch-board. Tendrils perform circumnutation from their apical regions. In this the terminal parts of tendrils move in all directions. Wherever they come in contact with a support, they stop performing cicumnutation. Instead, the contacted region shows little growth while the other side grows rapidly so that the tendril coils over the support.

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Question 2.
Name the nervous system which controls the functioning of internal organs. How does this system work ?
Answer:
Autonomous or visceral nervous system. The system does not consult the will of the individual. It works on its own inputs. Autonomous nervous system consists of only motor nerve fibres that innervate all organs and glands of the body. Depending upon the input, autonomous nervous system stimulates, slows down or stops the activity of an organ. For its working, autonomous or visceral nervous system has two components, sympathetic and parasympathetic. Sympathetic nervous system originates from thoracico-lumbar region, forms two ganglionic chains which send out long nerve fibres to various organs. The sympathetic nerve fibres activate the organs by release of nor-adrenaline. Parasympathetic nervous system is called cranio-sacral as it originates from some cranial and sacral nerves. It has long preganglionic fibres and ganglia attached to organs that are innervated. Its post ganglionic fibres secrete acetylcholine into organs for moderating or reducing their activity.

Question 3.
Which system is working when you start sweating during exercise ? What is its function ?
Answer:
Reflex activity of the nervous system. Actually 90% of nervous activity is performed through reflexes. It is automatic, involuntary and spontaneous response to a stimulus without consulting the will of the individual. Exercise increases body temperature. This can be harmful. Reflex action stimulates the sweat glands for releasing their secretion. Part of the sweat evaporates and cools, down the body.

Question 4.
You can become moody by simply switching on night bulb daily. How can this happen ?
Answer:
Night bulb reduces the secretion of melatonin hormone. Melatonin controls our day-night or circadian rhythm, healthy digestive and immune system, sexual cycle and moods. A reduced secretion causes insomnia and mood changes besides affecting health of our digestive and immune system.

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HOTS Questions for Class 10 Science Chapter 7 Control and Coordination

HOTS Questions for Class 10 Science Chapter 7 Control and Coordination

These Solutions are part of HOTS Questions for Class 10 Science. Here we have given HOTS Questions for Class 10 Science Chapter 7 Control and Coordination

Question 1.
What type of plant movement is seen in the diagram of coiling of tendril ?
HOTS Questions for Class 10 Science Chapter 7 Control and Coordination image - 1

                                                                  Or

How do auxins promote the growth of a tendril around a support? Describe in brief. (CCE 2012)
Answer:
Thigmotropism or curvature movement that occurs in response to contact. Less auxin is present in the region of contact. The free side having more auxin shows more growth. This causes the tendril to coil over the support.

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Question 2.
Identify and label the parts shown as A and B in the accompanying figure.
HOTS Questions for Class 10 Science Chapter 7 Control and Coordination image - 2
Answer:
Dorsal view of thyroid an parathyroid.
A – Thyroid,
B- Parathyroid.

Question 3.
What are the hormones involved in providing milk to the suckling infant ?
Answer:
1. Prolactin (Maternity Hormone). Production of milk.
2. Oxytocin Ejection of milk.

Question 4.
How does pancreas control glucose level of blood ?
Answer:
Pancreas produces two hormones

  1. Insulin from P-cells of islet of Langerhans and
  2. Glucagon from a- cells of islets of langerhans.

Insulin is produced when glucose level of blood rises. Insulin helps the cells to withdraw glucose from blood. It also converts glucose into glycogen in liver and muscles.

Question 5.
Glucagon is secreted when glucose level of blood falls. It mobilises reserve food like glycogen into glucose. What is pregnancy hormone ? Why is it known so ?
Answer:
Progesterone is called pregnancy hormone. It helps in maintaining pregnancy by non-formation of new ova, promoting thickening and secretory activity of uterine wall and attachment of embryo to the uterine wall.

Question 6.
What is dormin ?
Answer:
Dormin is the other name of plant hormone abscisic acid. The hormne induces dormancy in buds and seeds. So it has been called dormin.

Question 7.
(a)

  1. Name the parts labelled A and B in the neuron drawn above.
  2. Which part acquires the information in the neuron ?
    HOTS Questions for Class 10 Science Chapter 7 Control and Coordination image - 3
  3. Through which part does the information travel ?
  4. In what form does this information travel ?
  5. Where is the impulse converted into a chemical signal for onward transmission ?

(b) Name the hormone secreted by thyroid. What is the function ?
(c) Why is the use of iodised salt advisable ?
(CBSE A.I. 2008 Compt.)
Answer:
(a)

  1. A-Dendrite, B-Axon
  2. Dandrite.
  3. Dandrite to cell body or cyton to axon.
  4. Electrical impulse
  5. In the region of synapse.

Impulse stimulates the release of chemical neurotransmitter from the surface of presynaptic knob or bouton of axon terminal. Neurotransmitter (e.g. acetylcholine) comes in contact with chemoreceptor sites of post-synaptic membrane of the next neuron and generates a fresh impulse.

(b) Thyroxine:
Function of Thyroxine. It controls

  1. Basal metabolic rate
  2. Metabalism of carbohydrates, fats and proteins
  3. Consumption of energy in physical activity and body temperature
  4. Development and differentiation.

(c) Iodised Salt: Salt is iodised to provide iodine to thyroid for synthesis of thyroxine which is iodine containing hormone.

Question 8.
(a) What are plant hormones ? Give one example each of a plant hormone that

  1. promotes growth
  2. inhibits growth.
  3. promotes cell division
  4. promotes the growth of a tendril around a support. (CCE 2011)

(b) Name the parts labelled A, B and C in the diagram given below. Write one function of each part. (CBSE A.I. 2008 Comptt. Delhi 2008 Comptt.)
HOTS Questions for Class 10 Science Chapter 7 Control and Coordination image - 4
Answer:
(a) Plant Hormones:
Phytohormones are chemical substances other than nutrients produced naturally in plants which regulate growth, development, differentiation and a number of physiological processes, e.g., auxin, gibberellins, abscisic acid, cytokinins.

  1. Hormone That Promotes Growth. Auxin/Gibberellin.
  2. Hormone That Inhibits Growth. Abscisic acid or ABA
  3. Hormone That Promotes Cell Division. Cytokinin.
  4. Hormone That Promotes Growth of a Tendril Around a Support. Auxin.

(b) A-Pons Function: Relay centre, pneumotaxic area of respiratory centre.
B-Medulla Function: Reflex centre, cardiac centre, respiratory centre.
C-Cerebellum Function: Maintains equilibrium and coordinates muscular activities

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NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination

In this chapter 7 Control and Coordination, students will learn about the nervous system of animals, reflex actions, the human brain, how tissues are protected and how nervous tissues cause action, coordination in plants, hormones in animals.

NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination

These Solutions are part of NCERT Solutions for Class 10 Science. Here we have given NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination. Learn Insta provides you the Free PDF download of NCERT Solutions for Class 10 Science (Biology) Chapter 7 – Control and Coordination solved by Expert Teachers as per NCERT (CBSE) Book guidelines. All Chapter 7 – Control and Coordination Exercise Questions with Solutions to help you to revise complete Syllabus and Score More marks.

NCERT Questions

In Text Questions

Question 1.
What is the difference between reflex action and walking ?
Answer:

Reflex Walking/Voluntary
1.      Origin. Reflex action is inborn and present in an individual right from birth.

2.      Control. It is automatic. An individual cannot control it.

3.      Intensity. It cannot be changed.

4.      Value. It has survival and protective value.

It is acquired through learning.

It is under control of the will or brain.

It can be changed.

It has various functions, generally other than survival and protection.

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Question 2.
What happens at the synapse between two neurons ?
Answer:
NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination image - 1
At synapse, axon terminal is expanded to form presynaptic knob. The dendrite terminal that lies close to it is slightly broadened and depreseed to form post-synaptic depression. A fluid filled narrow space, called synaptic cleft, occurs between the two. When an impulse reaches the presynaptic knob, it stimulates the release of neurotransmitter into synaptic cleft. Neurotransmitter comes in contact with chemoreceptor sites of the membrane of postsynaptic depression. This generates an electrochemical signal or impulse in the dendrite part of second neuron.

Question 3.
Which part of brain maintains posture and equilibrium of the body ?
Answer:
Cerebellum.

Question 4.
How do we detect the smell of an agarbatti (incense stick) ?
Answer:
Burning of an agarbatti emits smoke having very large number of odorant molecules. They enter the nose along with inhaled air. The odorant molecules are trapped in mucus present over olfactory epithelium. Olfactory receptor cells have a number of non-motile olfactory hair containing special protein molecules. Contact between the two forms cyclic AMP that generates an impulse in the receptor cells. Nerve fibres coming out of the cells carry the information to olfactory bulbs which transmit the same to temporal lobes of cerebrum for interpretation.

Question 5.
What is the role of brain in reflex action ? (CCE 2010, 2015)
Answer:
It functions as a relay centre for transferring impulse from sensory to motor neurons in several reflex actions called cerebral reflexes, e.g, closure of eyes exposed to flash of light, salivation at the sight or smell of food. In spinal reflexes it acts as information collecting and evaluation centre without any direct involvement in reflex action.

Question 6.
What are plantohormones ?
Answer:
Phytohormones are chemical substances other than nutrients produced naturally in plants which regulate growth, development, differentiation and a number of physiological processes, e.g., auxin, gibberellins, abscisic acid, cytokinins.

Question 7.
How is movement of leaves of Sensitive Plant different from movement of shoot towards light ? (CCE 2015)
Answer:
Movement in the leaves of Sensitive Plant (Mimosa pudica) is haptonastic movement which occurs due to turgor changes in the cells of pulvinules and pulvinus. Movement of a shoot towards light is. phototropic movement that is caused by differential growth.

Question 8.
Give an example of a plant hormone that promotes growth ?
Answer:
Indole 3-acetic acid or IAA (auxin).

Question 9.
How do auxins promote the growth of a tendril around a support ? (CCE 2015)
Answer:
Less auxin occurs on the side of contact as compared to the free side. More growth occurs on the free side.
As a result of more growth on the free side, the tendril coils around the support.

Question 10.
Design an experiment to demonstrate hydrotropism. (CBSE 2010, CCE 2011)
Answer:
Apparatus: Trough with perforated base, saw dust, water, seeds of Pea/Gram, wooden support.
Procedure: Take a trough with perforated base. Fill it with saw dust. Moisten the same. Sow several seeds of Pea or Gram. Place the trough in slanting position by means of a wooden block. Keep the saw dust moist by sprinkling water at intervals. Observe after 2-3 days.
Observation: As the radicles come out of the seeds, they are seen to move towards the perforations. They come out of the pores and hang downwardly for some time under the influence of gravity. However, after some growth they bend back and enter the perforations to reach moist saw dust in complete disregard of gravity (Fig. 2.11).
NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination image - 2
Inference: Bending of radicles back into moist saw dust is hydrotropic movement. It occurs despite being against the force of gravity.

Question 11.
How does chemical coordination take place in animals ?
Answer:
In animals, chemical coordination is achieved through the agency of hormones which function as chemical messengers or informational molecules. Hormones are secreted by ductless glands in response to specific conditions or nervous stimulation. Timing and amount of a hormone released are regulated by feed-back mechanism. After a meal, sugar level of blood rises. It is detected by pancreas. Pancreas responds by producing hormone insulin from (3-cells of islets of Langerhans. Insulin causes glucose to be absorbed by all cells as well as get stored in liver and muscles in the form of glycogen. As the level of glucose falls in blood, insulin secretion is reduced.

Question 12.
Why is the use of iodised salt advisable ? (CCE 2011, 2015)
Answer:
Iodine is essential for synthesis of hormone thyroxine in thyroid gland. Thyroxine controls basal metabolic rate, physical activity, body temperature, heart beat, mental, physical and sexual development besides regulating carbohydrate, protein and fat metabolism. Deficiency of thyroxine disturbs metabolic, physical and mental activities besides causing disorders of simple goitre, cretinism and myxedema. Therefore, it is always advisable ^ to take iodised salt so that there is no deficiency of iodine.

Question 13.
How does our body respond when adrenaline is secreted into blood ?
Answer:
Adrenaline/emergency hormone/triple F hormone

  1. Reduces blood supply to peripheral blood vessels and gastrointestinal tract,
  2. More blood flows to skeletal and heart muscles.
  3. Increases breathing and gives more oxygen to muscles,
  4. Increases heart rate,
  5. Mobilises more glucose to muscles for higher activity.

Question 14.
Why are some patients of diabetes treated by giving injections of insulin ?
Answer:
Diabetes mellitus is of two types, insulin dependent and insulin independent. In insulin dependent diabetes, pancreas is unable to produce required quantity of insulin. As a result blood sugar continues to rise and part of sugar is excreted through urine resulting in diabetes. This is kept under check by regular injection of insulin. Availability of insulin will help the cells to take up glucose while liver and muscles are induced to store excess of glucose as glycogen.

NCERT Chapter End Exercises

Question 1.
Which of the following is a plant hormone ?
(A) Insulin
(B) Thyroxine
(C) Oestrogen
(D) Cytokinin.
Answer:
(D).

Question 2.
The gap between two neurons is called
(A) Dendrite
(B) Synapse
(C) Axon
(D) Impulse.
Answer:
(B).

Question 3.
The brain is responsible for
(A) Thinking
(B) Regulating the heart beat
(C) Balancing
(D) All the above.
Answer:
(D).

Question 4.
What is the function of receptors in our body ? Think of situation where receptors do not work properly. What problems are likely to arise ? (CCE 2011)
Answer:
Receptors are specialised cells, tissues, organs and nerve endings which are able to pick up specific stimuli, e.g., photoreceptors, gustatoreceptors, thermoreceptors, photoreceptors, statoreceptors, tangoreceptors, pain and pressure receptors. Receptors provide sensory input about external and internal environment. Without them, an animal will not able to observe, handle and taste food. It will not be aware of an approaching enemy. The animal may not be able to correct its position and fall down repeatedly if its statoreceptors are damaged. Therefore, the animal will not be able to perform the activities connected with the defective receptors.

Question 5.
Draw the structure of a neuron and explain its functions. (CCE 2011, 2013)
Answer:
NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination image - 3
Functions:

  1. Dendrites. Picking up sensations and transmitting the same to cell body.
  2. Cell Body,
    1. Sustaining structure and function of dendrites and axon,
    2. Functioning as passage¬way for transmission of sensation or impulse to axon.
  3. Axon. Carrying impulse to another neuron, muscle, gland and organ. A single impulse can be transmitted to several structures with the help of axon terminals.

Mechanism of Impulse Transmission:
Impulse is a self propagated electrical current that travels from one end to another of a neuron for the passage of a message.

The pathway is stimulus ——— >dendrite ——- > cell body ——- > axon——– > axon terminal ——– > passage of stimulus.

A stimulus received by a neuron travels through it in the form of an electrical disturbance. During rest the outer surface of a neuron is positively charged while the interior has negative charge. Stimulus causes opening of ion channels which makes the outer surface negatively charged while the interior becomes positively charged. This creates the impulse which moves forward. The posterior region returns to the condition of rest. At the end of the neuron, the impulse is passed on to the next neuron, an organ, muscle or gland in the form of a neurotransmitter. Neurotransmitter is a chemical secreted by axon terminal for transmission of impulse to the next neuron, muscle, gland or organ, e.g., acetylcholine, noradraneline, glutamic acid.

Question 6.
How does phototropism occur in plants ?
Answer:
It is directional growth movement of curvature which occurs in response to unidirectional exposure to light. The region of photoperception is sho.ot apex while the region of response is in the area of elongation. The light effective in phototropic response is blue light. The photoreceptor is a flavoprotein called phototropin. Leaves are essential for producing the response.
Stems generally bend towards the direction of light. They are positively phototropic. Leaves generally come to lie at right angles to light. They are diaphototropic. Roots are either neutral (non-phototropic) or negatively phototropic. Positively phototropic heads of Sunflower perform solar tracking as they move from east to west along the direction of sun.
Phototropic movement is generally caused by increased auxin on the dark side and lesser auxin on the illuminated side. It causes more growth on the dark side of stem causing it to bend towards the source of light. The opposite happens in root where less auxin stimulates growth while higher auxin inhibits growth.
In the plant growing in the open, sunlight is received from above. Auxin diffuses equally on all sides so that the stem does not bend but grows straight vertically.

Question 7.
Which signals will get disrupted in case of spinal cord injury ?
Answer:

  1. Sensory impulses from the area innervated by injured portion,
  2. Transmission of motor impulses through the injured portion,
  3. Reflex action in the area of injury. Sensations and movements are restricted.

Question 8.
How does chemical coordination occur in plants ?
Answer:
Plants produce a number of hormones which control and coordinate their functioning. Amount of hormone depends upon the environment and other stimuli. Its effect is also regulated by its antagonistic * hormone, e.g., auxin and abscisic acid. The effect is enhanced by synergic presence of another hormone, e.g., auxin and gibberellin.

Question 9.
What is the need for a system of control and coordination in an organism ?
Answer:
The body of a multicellular organism consists of a number of components and sub-components, each specialised to perform a particular fonction. However, all the components are not required to fonction all the time at the same speed. A system of controls is required to allow them to perform or not to perform, slow down or speed up their working. Further, most activities require the simultaneous or sequential functioning of a number of parts, stopping some and stimulating others. During feeding, eyes locate the food, nose registers its smell, hands pick up the food and take it to mouth, mouth opens to receive the food, teeth and muscles take part in its mastication and saliva moistens it. Tongue perceives its taste. It moves the food below the teeth. Later it pushes the crushed food into pharynx. All this is possible only through a system of coordination.

Question 10.
How are involuntary actions and reflex actions different from each other ?
Answer:
Refex actions are involuntary in nature which are carried out to meet emergencies. However, all involuntary actions are not reflex actions. They fulfill critical life processes, e.g., circulation of blood, movement of food in food pipe.

Question 11.
Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
Answer:
Nervous system controls and coordinates many body functions as it has a well spread network of neurons. Messages travel very fast, in the form of electrical impulses. However, it has limitations,

  1. Nerve impulses do not reach each and every cell of the body,
  2. The effect of nerve impulse is of short duration,
  3. Nerve impulses cannot pass continuously.

A small gap is required between two impulses. These short-comings are overcome in endocrine system. Here, the stimulated glandular cells secrete chemicals that diffuse throughout the body. Cells have receptors for picking up chemical information. The information can pass persistendy. The passage of information is, of course, slower. It, however, influences all the cells of the target. A multiple effect can also be produced. Adrenaline reduces blood supply to skin and digestive system but increases the same to skeletal or voluntary muscles. There is increase in breathing rate and heart beat. The body becomes ready to deal with an emergency. Further, endocrine system controls and coordinates many processes of the body where nervous system has no role, e.g., cell permeability, cell division, cell growth, cell differentiation, development of sex organs, secondary sex characters and several other activities. Any discrepancy can lead to a disorder, e.g, dwarfism and gigantism, hypothyroidism (simple goitre, cretinism, myxedema), hyperthyroidism (exophthalmia).

Question 12.
What is the difference between the manner in which movement in Sensitive Plant and movement in our legs takes places ?
Answer:

NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination image - 4

Selection Type Questions

Alternate Response Type Questions
(True/False, Right(√)/Wrong (x), Yes/No)

Question 1.
Fore brain is centre of intelligence, control of movements, hearing, smell and sight.
Question 2.
Chewing cud is a movement of growth.
Question 3.
Immediate response to stimulus is shown by Mimosa pudica.
Question 4.
Rise in sugar level in blood stops secretion of insulin by pancreas.
Question 5.
Control and coordination are functions of nervous and endocrine systems.
Question 6.
Stems are positively geotropic while roots are negatively geotropic.
Question 7.
Major part of taste is smell.
Question 8.
I withdrew my hand back from hot plate reflexly.

Matching Type Questions

Question 9.
Match the articles in columns I and II (single matching) :

Column I

Column II

(a)   Cell growth

(b)   Wilting

(c)   Emergency

(d)    Electrical impulses

(i) Abscisic acid

(ii) Nerve conduction

(iii) Adrenaline

(iv) Auxin.

Question 10.
Match the contents of columns I, II and III (double matching) :

Column I Column II Column III

(a)    Thyroid

(b)    Shoot tip

(c)     Receptor

(d)    Motor end plate

(i)     Reflex arc

(ii)  Neuromuscular junction

(iii) Thyroxine

(iv) Auxin

p.   Iodine

q.  Acetylcholine

r.  Apical dominance

s.  Effector

Question 11.
Name the control — voluntary (V), involuntary (I) and endocrine (E) in the following (Key or Check list Items) :
Action                                         Control
(i) Peristalsis                             ………………..
(ii) Lifting of arms                     ……………….
(iii) Growth                               ……………….
(iv) BMR                                   ………………..

Question 12.
Match each stimulus with appropriate response :

Hormone Dwarfism
(A)
Cretinism
(B)
Pregnancy
(C)
Calcium level (D) Dilute urine (E) Mammary glands
(F)

(i) Thyroxine

(ii) Growth hormone

(iii) Parathormone

(iv)  Prolactin

(v)    Vasopressin

(vi)  Progesterone

Fill In the Blanks

Question 13. A ………………… mechanism regulates the action of hormones.
Question 14. An axon terminal passes the electrical stimulus to a dendrite of next neuron through …………………. reaction.
Question 15. Reflex arc formed in spinal cord also sends information input to ………………… .
Question 16. ……………………….. coordinates the activity of picking up pencil for writing.
Question 17. Positive geotropism of root is due to greater growth on ……………………… side as compared to ………………… side.

Answers:
NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination image - 5

NCERT Solutions for Class 10 Science Chapter 7 – Control and Coordination

Hope given NCERT Solutions for Class 10 Science Chapter 7 are helpful to complete your science homework.

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NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes

NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes

These Solutions are part of NCERT Exemplar Solutions for Class 10 Science. Here we have given NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes

NCERT Exemplar Solutions for Class 10 Science Chapter 6 Short Answer Questions

Question 1.
Name the following :

    1. The process in plants that links light energy with chemical energy.
  1. Organisms that can prepare their own food.
  2. Cells that surround a stomatal pore.
  3. The cell organelle where photosynthesis occurs.
  4. Organisms that cannot prepare their own food.
  5. An enzyme secreted by gastric glands in stomach that acts on proteins.

Answer:

  1. Photosynthesis
  2. Autotrophs
  3. Guard cells
  4. Chloroplast
  5. Heterotrophs
  6. Pepsin.

More Resources

Question 2.
“All plants give out oxygen during day and carbon dioxide during night.” Do you agree with the statement ? Give reason.
(CCE 2010)
Answer:
Yes. Respiration is going on throughout day and night. Photosynthesis occurs only during the day. Rate of photosynthesis is several times the rate of respiration. All the CO2 produced in respiration is also consumed in photosynthesis during the day time. Therefore, during day time, plants give out oxygen, which is a product of photosynthesis. However, during night when there is no photosynthesis, plants liberate carbon dioxide.

Question 3.
How do the guard cells regulate opening and closing of stomatal pores ? (CCE 2010, 2012)
Answer:
Opening and closing of stomata is regulated by gain or loss of turgidity of their guard cells. During opening of stomata, guard cells withdraw K+ ions from surrounding epidermal cells, followed by absorption of water from them. As a result, guard cells swell up and become turgid. Their outer thin and elastic walls bend outwardly followed by outward movement of thicker inner walls. The latter creates a pore in between the two guard cells.
During closure movement of stomata, guard cells send out K+ ions. Water also passes out. Guard cells become flaccid. Their inner thick walls come to touch each other. The stomatal pore gets closed.

Question 4.
Two green plants are kept separately in oxygen free containers, one in dark and the other in continuous light. Which one will live longer ? Give reasons. (CCE 2010)
Answer:
Plant kept in continuous light will live longer due to

  1. Manufacture of food and hence its availability to the plant for maintenance and growth,
  2. Production of oxygen in photosynthesis and its availability for respiration of the plant. Plant kept in oxygen free container kept in dark will die within a few days due to non-availability of food and oxygen.

Question 5.
If a plant is releasing carbon dioxide and taking in oxygen during the day, does it mean that there is no photosynthesis occurring ? Justify your answer.
Answer:
A plant releases carbon dioxide and takes in oxygen only when photosynthesis is either absent or too small as not to compensate for respiration.
(In photosynthesis, plants absorb CO2 and release O2. The normal rate of photosynthesis is many times the rate of respiration. As a result, CO2 produced during respiration is consumed and a lot of more is absorbed from outside. Oxygen produced during photosynthesis is much more than required for respiration. Therefore, oxygen passes out.)

Question 6.
Why do fishes die when taken out of water ?
Answer:
Fish taken out of water die due to

  1. Inability to obtain oxygen from air
  2. Collapsing of gill lamellae so that no space is left for gaseous exchange.

Question 7.
Differentiate between an autotroph and a heterotroph.
Answer:

Autotroph Heterotroph
1. Food: It manufactures its own food. It obtains its food from outside sources.
2. Chlorophyll: It has chlorophyll for performing photosynthesis. Chlorophyll is absent.
3. Energy: It is obtained from sunlight and changed into chemical energy. It does not require an external source of energy as the same is present in food obtained from outside.
4. Digestion: It is absent. Food obtained from outside is digested before being absorbed and assimilated.

Question 8.
Is nutrition a necessity for an organism ? Discuss.
Answer:
Yes, nutrition is a must for an organism because of the following reasons :
Importance of Nutrition/Food

  1. Food provides energy: Energy is required by the body all the time, whether asleep, taking rest or doing work. When the body is not doing any apparent work, energy is still being consumed in maintaining order. Further, biosynthetic activities continue for replacing materials being consumed or degraded. A number of other activities are going on all the time. Heart is always beating. Breathing movements never stop. Food eaten by a person has to be digested and absorbed. Excretory products are being produced.
  2. Body Structure: All body components are built up of materials obtained from food.
  3. Food is used in building protoplasm. More protoplasm is required for formation and enlargement of cells that take part in growth of the organism.
  4. Food provides materials for replacement and repair of worn out or damaged structures.
  5. Hormones and enzymes are formed from ingredients of food. They regulate metabolism and body functions.                                                                ‘
  6. Defence system of the body is formed from raw materials got- from food.
  7. Food provides materials to form reproductive structures.

Question 9.
What would happen if green plants disappear from earth ?
Answer:
Herbivores will die of starvation followed by carnivores and then decomposers.

Question 10.
Leaves of a healthy plant were coated with vaseline. Will this plant remain healthy for long ? Give reasons for your answer.
Answer:
The plant will not remain healthy for long. Vaseline covers the cuticle and blocks the stomata. As a result

  1. It is unable to obtain oxygen from air for respiration,
  2. It is unable to perform photosynthesis as no carbon dioxide diffuses from air.
  3. In the absence of transpiration, the leaves get heated up and injured.

Question 11.
How does aerobic respiration differ from anaerobic respiration ?
Answer:

Aerobic Respiration Anaerobic Respiration
1. Method: It is the common method of respiration. It occurs permanently only in a few organisms. In others it may occur as a temporary measure to overcome shortage of oxygen.
2. Steps: It is completed in 3 steps—glycolysis, Krebs cycle and terminal oxidation. There are two steps— glycolysis and anaerobic breakdown of pyruvic acid.
3. Oxygen: It requires oxygen. Oxygen is not required.

Question 12.
Match the words of column A with those of column B

A B

(a)  Phloem

(b)   Nephron

(c)  Veins

(d)  Platelets

(i)   Excretion

(ii)  Translocation of food.

(iii)   Clotting of blood

(iv)   Deoxygenated blood.

Answer:
a — ii,
b — i,
c —iv,
d —iii.

Question 13.
Differentiate between an artery and a vein. (CCE 2013)
Answer:

Artery Vein
1. Direction of Flow: It carries blood from heart to an organ. It brings blood from an organ towards the heart.
2. Speed: Blood flow is rapid in artery. Blood flow is slow in vein.
3. Jerks: Blood flows with jerks. Blood flows smoothly.
4. Pressure: Blood flows under pressure There is little pressure.
5. Internal Valves: They are absent. Internal valves are present to prevent back flow.
6. Wall: It is thick and elastic. It is comparatively thinner and little elastic.
7. Lumen: Narrow. Wide.
8. Type of Blood: Artery carries oxygenated blood except pulmonary arteries. Vein carries deoxygenated blood except pulmonary veins.
9. Occurrence: It is deep seated. It is superficial.
10. Collapsibility: Artery is not collapsible. Vein is collapsible.
11. Blood After Death: It does not contain blood after death. Vein is full of blood even after death.

Question 14.
What are the adaptations of leaf for photosynthesis ?
Answer:

  1. Large Surface Area : Leaf has a large surface area to absorb maximum amount of lift.
  2. Leaf Orientation: It is such as to absorb the optimum amount of light.
  3. Veins: A number of veins occur in a leaf. They provide mechanical strength to the otherwise soft leaf. Veins also take part in quick transport of substances to and from the mesophyll cells.
  4. Transpiration: Leaf is the seat of transpiration. Transpiration cools the surface of leaf for optimum photosynthesis.
  5. Gaseous Exchange: A leaf has a large number of stomata for gaseous exchange, required for photosynthesis.
  6. Chloroplasts: A very large number of chloroplasts occur in the mesophyll of a leaf for efficient photosynthesis.

Question 15.
Why is small intestine in herbivore longer than in carnivores ? (CCE 2013)
Answer:
Herbivorous diet has a large bulk. It is rich in cellulose. However, cellulose digesting enzymes are absent in them. For digestion
of cellulose, herbivores depend upon bacteria. The food has to be kept for longer period in the intestine for complete digestion of cellulose. Therefore, small intestine where bacterial digestion of cellulose occurs has to be long. There is no such requirement in carnivores as their diet has a smaller bulk which does not contain cellulose. They have a shorter intestine.

Question 16.
What will happen if mucus is not secreted by gastric glands ?
Answer:
Mucus protects the stomach from corrosion by HCl and pepsin of gastric juice. In the absence of mucus, the lining layer of stomach wall will be corroded forming gastric ulcers. There will be excessive acidity and extreme discomfort.

Question 17.
What is the significance of emulsification of fats ?
Answer:
Emulsification of fat is the conversion of large fat pieces into very fine fat globules which can be efficiently acted upon by lipase.

Question 18.
What causes movement of food inside the alimentary canal ?
Answer:
Involuntary movement consisting of rhythmic contraction and expansion of the alimentary canal called peristalsis.

Question 19.
Why does absorption of digested food occur mainly in the small intestine ?
Answer:

  1. Digestion of food is completed only in small intestine.
  2. Wall of the intestine bears a number of finger-like projections called villi. Villi provide a large surface area to the lining layer for absorption.
  3. The epithelium, lining the villi, is made of cells having a number of very fine projections known as microvilli. Microvilli are specialised for absorption.
  4. Wall of the intestine, especially the interior of villi, has lymph and blood vessels for carrying the absorbed food to different parts of the body.

Question 20.
Match the articles of columns A and B :

A B

(a)  Autotrophic nutrition

(b)  Heterotrophic nutrition

(c) Parasitic nutrition

(d)  Digestion in food vacuoles

(i) Leech

(ii) Paramoecium

(iii)   Deer

(iv)    Green plant.

Answer:
a — iv,
b — iii,
c—i,
d — ii.

Question 21.
Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms ? (CCE 2011, 2012)
Answer:
Most of the aquatic organisms obtain oxygen from water. The amount of dissolved oxygen is quite small as compared to the amount of oxygen in air. Therefore, in order to obtain required oxygen from water, the aquatic animals like fishes have to breathe much faster as compared to the terrestrial organisms.

Question 22.
Why is blood circulation in human heart called double circulation ? (CCE 2011)
Answer:
Blood circulation in human heart is called double circulation as blood passes twice through the heart in order to complete one cycle—once through right side as deoxygenated blood and once through left side as oxygenated blood. Deoxygenated blood passes to lungs. It returns to left side as oxygenated blood. Oxygenated blood is supplied to different parts of the body. It returns to right side of the heart as deoxygenated blood.

Question 23.
What is the advantage of having four chambered heart ? (CCE 2010)
Four chambered heart ensures complete separation of oxygenated and deoxygenated bloods. Only oxygenated blood is pumped out to supply all parts of the body. It is received by left auricle from lungs and pumped out by left ventricle. The blood returns to heart after deoxygenation. It is received by right auricle and pumped out by right ventricle to lungs for oxygenation. The mechanism is useful to animals with high energy needs (due to thermoregulation and higher activity) such as birds mammals.

Question 24.
Mention the major events during photosynthesis. (CCE 2011, 2012)
Answer:

  1. Photolysis: With the help of light energy, oxygen evolving Z-complex splits up water into its components —- protons (H+), electrons (e) and oxygen.
    NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 1
  2. Absorption of Light Energy: Chlorophyll absorbs light energy.
  3. Primary Reaction: Chlorophyll converts the absorbed light energy into chemical energy. It is called primary reaction of photosynthesis. It builds up ATP with the help of excited electrons.
  4. Formation of Reducing Power: Coenzyme NADP+ is changed to reduced form of NADPH.
    NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 3
  5. Reduction of CO2: Carbon dioxide is reduced enzymatically with the help of NADPH and ATP to form carbohydrates.
    NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 4

Question 25.
In each of the following situations, what happens to the rate of photosynthesis ?
(a) Cloudy days
(b) No rainfall in the area
(c) Good manuring
(d) Stomata get blocked due to dirt.
Answer:
(a) Cloudy Days: Photosynthesis is reduced due to low light intensity.
(b) No Rainfall: Rate of photosynthesis decreases due to wilting of leaves, closure of stomata and reduced availability of hydration.
(c) Good Manuring: Rate of photosynthesis increases as good manuring increases soil fertility by providing more minerals, moisture and aeration.
(d) Blocked Stomata: It decreases the rate of photosynthesis by reducing gaseous exchange and non-cooling of leaves due to reduced transpiration.

Question 26.
Name the energy currency in the living organisms. When and where is it produced ?
Energy Currency. ATP (adenosine triphosphate) is the energy; currency of the living beings.
It is produced both during respiration (in all organisms) and photosynthesis (in plants only).

Question 27.
What is common amongst Cuscuta, Ticks and Leeches ?
Answer:
All are parasites which obtain their nutrition from their hosts direcdy without killing them.

Question 28.
Explain the role of mouth cavity in digestion of food.
Answer:

  1. Moistening of food with saliva,
  2. Tongue helps in thorough mixing of food with saliva.
  3. Crushing of food into smaller pieces by teeth,
  4. Partial digestion of starch by enzyme amylase contained in saliva,
  5. Rolling of crushed, moistened and partially digested food into small ball or bolus by the tongue.

Question 29.
What are the functions of gastric glands present in the wall of stomach ? (CCE 2011)
Answer:
Gastric glands produce the following substances :

  1. Mucus: Moistening the food and protecting the wall of the stomach from corroding action of HCl and pepsin.
  2. HCl: It makes the food soft, sterilised and acidified for pepsin to act upon food.
  3. Gastric Lipase: It is active only in infants. It partially breaks down fat into its components.
  4. Rennin: It is active in infants where it helps in curdling of milk (casein to paracasein) for action of pepsin.
  5. Pepsin: It is secreted in inactive state of pepsinogen. Pepsin hydrolyses proteins into soluble fragments of peptones and proteoses.

Question 30.
Match the items of columns A and B

A B

(a)  Trypsin

(b)  Amylase

(c) Bile

(d)  Pepsin

(i) Pancreas

(ii) Liver

(iii)   Gastric glands

(iv)     Saliva

Answer:
a — i,
b — iv,
c — ii,
d — iii.

Question 31.
Name the correct substrates for the following enzymes :
(a) Trypsin
(b) Amylase
(c) Pepsin
(d) Lipase.
Answer:
(a) Trypsin: Proteins, peptones and proteoses,
(b) Amylase: Starch, dextrins.
(c) Pepsin: Proteins.
(d) Lipase: Fats.

Question 32.
Why do veins have thin walls as compared to arteries ?
Answer:
In arteries, blood flows under pressure so that their walls are thick and elastic. In veins the blood is Therefore, their walls are thin. Rather, they possess semilunar valves to check back flow of blood.

Question 33.
What will happen if platelets were absent in the blood ?
Answer:
Blood platelets are a source of thromboplastin which is essential for blood clotting at the place of injury. In the absence of blood platelets, blood clotting will be litde resulting in greater loss of blood from the place of injury.

Question 34.
Plants have low energy needs as compared to animals. Explain.
Answer:
Plants are anchored. They do not move about. Most of their body is made of dead cells and cell walls. Therefore, their requirement for energy is quite low as compared to animals which move about fast in search of food, mate and shelter.

Question 35.
Why and how does water enter continuously into root xylem ?
Answer:
Root cells in the absorbing part of root pick up ions actively from soil. Ions pass inwardly increasing osmotic concentration of xylem. Because of it soil water (which has very low osmotic concentration) continuously passes into root xylem.

Question 36.
Why is transpiration important for plants ?
Answer:
Importance

  1. Cooling: Evaporation of water from the aerial parts results in lowering of their temperature which will otherwise rise due to exposure to sun.
  2. Concentration of Minerals: Transpiration helps in increasing concentration of minerals present in rising water.
  3. Transport: It creates a pull that helps in transport of water and minerals.

Question 37.
How does leaves of plants help in excretion ? (CCE 2016)
Answer:
Waste materials produced in plant cells are stored ’in their vacuoles. In leaves, the waste materials are

  1. Stored in vacuoles of mesophyll and epidermal cells,
  2. Oxalic acid is crystallised as calcium oxalate.
  3.  Nitrogenous wastes are changed into alkaloids
  4. Vaste aromatic compounds are changed into tannins. As the old leaves fall, the waste materials are also removed from the plant.

NCERT Exemplar Solutions for Class 10 Science Chapter 6 Long Answer Questions

Question 38.
Explain the process of nutrition in Amoeba.
Answer:

  1. Ingestion: (L. ingestus — taken in). It is taking in of solid food with the help of temporary or permanent mouth. Amoeba can ingest food particles from any point on its surface. Paramoecium (another unicellular organism) has fixed point for the same. Amoeba captures food with the help of temporary finger-like processes called pseudopodia. Paramoecium has small hair-like processes called cilia. Beating of cilia creates current in water that pushes food particle through cytostome or cell mouth. The process of ingestion of solid food particle by a cell or unicellular organism is called phagocytosis.
    As soon as Amoeba comes in contact with a food particle or prey, it throws pseudopodia all around the same. The tips of encircling pseudopodia fuse and the prey comes to lie in a vesicle or phagosome.
    NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 5
  2. Digestion: It is conversion of complex insoluble food ingredients into simple absorbable form. Digestion can be intracellular or intercellular. Intercellular digestion occurs in a digestive tract. Intracellular digestion takes place in the cytoplasm of cells. Here, a lysosome fuses with phagosome to produce a food vacuole, also called gastriole or temporary stomach. Reaction of food vacuole is acidic at first and alkaline later on. Digestion of food occurs with the help of digestive enzymes brought by lysosome. It changes complex insoluble substances of food into simpler absorbable substances.
  3. Absorption: The digested simple and soluble substances pass out of food vacuole into the surrounding cytoplasm.
  4. The absorbed food materials are converted into various constituents of protoplasm including food reserve.
  5. (L. egestus — discharge): It is throwing of undigested components of food out of the body. In Amoeba, the old food vacuole with heavier undigested material reaches the rear end, passes to the surface, fuses with surface membrane and throws out the undigested materials. The process is called egestion. Paramoecium has a definite cytopyge or cell anus.

Question 39.
Describe the alimentary canal of man.
Answer:
Alimentary canal (L. alere-to nourish) is a tubular passage extending from mouth to anus through which food passes during its digestion and absorption. It is about 9 metres in length. Alimentary canal consists of mouth, buccal cavity, oesophagus, stomach, small intestine, large intestine and anus.
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 6

  1. Mouth: It is a transverse slit like aperture that occurs in between the nose and the chin. Mouth is bounded by two soft, movable sensitive lips, upper and lower. Lips help in holding the food. They also aid in phonation (speech).
  2. Buccal or Oral Cavity (L. bucca-cheek): It is anterior part of alimentary canal that extends from mouth to pharynx and lies between two jaws, upper (fixed) and lower (movable). It has palate on upper side, throat and tongue on the lower side and cheeks on the lateral sides. Both the jaws contain teeth in semicircular rows or arches.
    1. It is a muscular, sensory, movable and protrusible flat structure which is attached posteriorly over the lower jaw. Tongue bears taste buds for tasting the quality of food—sweet anteriorly, salt anterio-laterally, sour postero-laterally and bitter posteriorly. It moves food in ‘the buccal cavity for crushing under teeth, mixing with saliva and pushing the food during swallowing. Tongue cleans the teeth. It also aids in phonation (speech). It functions as a movable spoon during drinking.
    2. They are hard structures which are used for cutting, chewing and crushing the food (physical digestion). They are partially embedded in sockets of jaw bones (thecodont). Teeth are made of ivory like substance called dentine. The exposed parts of teeth or crowns are covered by a shining substance called enamel. Enamel is the hardest substance of the body.
    3. Salivary Glands. Three pairs of salivary glands (saliva secreting glands) open into buccal cavity. They are parotid (below ears), sub-maxillary (at the angles of lower jaw) and sublingual (below tongue). About 1-0-1-5 litres of near neutral saliva is poured into buccal cavity every day. Saliva consists of mucus, water, lysozyme and enzyme ptyalin.

Question 40.
Explain the process of breathing in man.
Answer:
Breathing or the process of taking in fresh air and releasing foul air can be easily observed because thorax shows alternate expansion and contraction. It is involuntary though it can be prevented for a brief period. Rate of breathing is controlled by respiratory centre of brain. Expansion of thorax causes fresh air to be drawn in. Contraction of thorax causes foul air to be expelled. Therefore, breathing consists of two steps, inspiration and expiration.

  1. Inspiration or Inhalation: It is bringing of fresh air into lungs for exchange of gases. During inhalation, thoracic cavity enlarges due to two types of inspiratory muscles, phrenic and external intercostals. Phrenic muscles straighten the diaphragm by moving its curved part downwards. It increases length of thorax. Contraction of external intercostal muscles pushes the rib cage in outward and upward direction. It increases girth of thorax. Being air tight, increase in size of thoracic cavity causes expansion of lungs. It decreases air pressure in the lungs. As a result outside air rushes into lungs through external nostrils, nasal cavities, internal nostrils, pharynx, larynx, trachea, bronchi, bronchioles to alveoli. While passing through respiratory tract, the incoming air is :
    1. Filtered by hair present in anterior part of nasal cavities.
    2. Cleansed of dust and microbes throughout respiratory tract by lysozyme, mucus and cilia.
    3. Air conditioned (bringing temperature of inhaled air to that of body) with the help of blood capillaries present below nasal epithelium.
    4. Moistened by water vapours from wet epithelium.
  2. Exchange of Gases: It occurs in the alveoli. Fresh air has high concentration of oxygen and a very low concentration of carbon dioxide. As a result, oxygen diffuses from alveolar air to blood present in capillaries around the alveoli. Carbon dioxide diffuses from blood into alveolar air.

Question 41.
How do carbohydrates, proteins and fats get digested in human beings ?
Answer:
Carbohydrates:    Glucose.
Proteins:               Amino acids.
Fats:                      Fatty acids and   glycerol.
Hints:

  1. Carbohydrates: In mouth cavity (by saliva), duodenum (by pancreatic juice) and jejunum (by intestinal juice).
  2. Proteins: In stomach (by gastric juice), duodenum (by pancreatic juice) and jejunum (by intestinal juice).
  3. Fats: In duodenum and jejunum (by pancreatic juice aided by bile salts). Also in infants in stomach.

Question 42.
Explain the mechanism of photosynthesis.
Answer:
Mechanism of Photosynthesis:
Photosynthesis is formation of organic food from carbon dioxide and water with the help of sunlight inside chlorophyll containing cells. Oxygen is produced as by-product.
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 7
Oxygen comes from water. Hydrogen of water is used to reduce carbon dioxide to form carbohydrate.
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 8
Actually, photosynthesis occurs in two steps, photochemical and biochemical.
1. Photochemical Phase (Light or Hill Reaction): The reactions of this phase are driven by light energy. They are of two types— photolysis of water and formation of assimilatory power.
(a) Photolysis of Water. Light energy splits up water into its components. Mn2+, CL and Ca2+ are required for this.
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 9
(b) Formation of Assimilatory Power: Light energy absorbed by chlorophyll molecules is used in synthesis of ATP and NADPH.
Both ATP and NADPH2 together form assimilatory power.
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 10
2. Biosynthetic Phase (Dark or Blackman’s Reaction). It is actually light independent reaction which can occur both in light as well as in dark. It requires the energy and reducing power contained in assimilatory power of light reaction. Common pathway of biosynthetic phase is Calvin cycle. Carbon dioxide combines with ribulose bisphosphate in the presence of enzyme ribulose biphosphate carboxylase or rubisco. It produces two molecules of phosphoglyceric acid (PGA).
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 11
3. In the presence of ATP, phosphoglyceric acid is reduced by NADPH2 to form glyceraldehyde phosphate (GAP).
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 12
4. A part of glyceraldehyde phosphate is changed into dihydroxyacetone phosphate. The two condense and form glucose. Ribulose biphosphate is regenerated to combine with carbon dioxide again. Glucose undergoes condensation to form reserve carbohydrate called starch.
5. Other inorganic Raw Materials: Synthesis of carbohydrates during photosynthesis is a mechanism to form food materials for body building and releasing energy.
NCERT Exemplar Solutions for Class 1
Plants also require a number of other inorganic raw materials or minerals from soil for building other, e.g., nitrogen, phosphorus, iron, sulphur, magnesium, etc. Nitrogen and sulphur are required for building proteins. Phosphorus is required for synthesis of nucleotides. Minerals are absorbed in the form of ions, e.g., NO2 and NH4+ for nitrogen. Some bacteria convert atmospheric nitrogen into compounds of nitrogen. Parts of them become available to plants.

Question 43.
Explain the three pathways of breakdown (respiration) in living organisms.
Answer:
(i) Aerobic Respiration:
It is a multistep complete oxidative breakdown of respiratory substrate into carbon dioxide and water with the help of oxygen acting as a terminal oxidant. Aerobic respiration is the usual mode of respiration in all higher organisms and most of the lower organisms. The reason is that it yields maximum amount of energy. The energy is stored in some 38 molecules of ATP.
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 14
Aerobic respiration occurs in two steps, glycolysis and Krebs cycle.
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 15
Glycolysis: Glycolysis or EMP (Embden, Meyerhof and Parnas) pathway is the first step of respiration which is common to both aerobic and anaerobic modes of respiration. It occurs in cytoplasm. Respiratory substrate is double phosphorylated before it undergoes lysis to produce 3-carbon compound, glyceraldehyde phosphate. NADH2 and ATP are produced when glyceraldehyde is changed to pyruvate. The net reaction of glycolysis is :
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 16
Krebs Cycle (Krebs, 1940): It is also known as citric acid cycle or tricarboxylic acid cycle (TCA cycle). Pyruvic acid or pyruvate passes into mitochondria. It undergoes oxidative decarboxylation to produce acetyl CoA, carbon dioxide and NADH2. Acetyl CoA enters Krebs cycle. Here two decarboxylations, four dehydrogenations and one phosphorylation or ATP synthesis occur.
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 17
NADH2 and FADH2 liberate electrons and hydrogen ions. They are used in building up ATP molecules and activating oxygen molecules to combine with hydrogen for forming water. Synthesis of ATP from ADP and inorganic phosphate with the help of electron generated energy during oxidation of reduced coenzymes (NADH2, FADH2) is called oxidative phosphorylation. Water formed in respiration is called metabolic water. As oxygen is used at the end of Krebs cycle for combining with hydrogen, the process is called terminal oxidation.
The overall equation of aerobic respiration using glucose as substrate is
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 18
(ii) Anaerobic Respiration Producing Alcohol:
It is a multistep breakdown of respiratory substrate in which atleast one end product is organic and which does not employ oxygen as an oxidant. Anaerobic respiration occurs in many lower organisms, e.g., certain bacteria, yeast. In human body it occurs regularly in red blood cells and during heavy exercise in muscles (striated muscles). Anaerobic respiration occurs entirely in the cytoplasm. It has two steps. The first step is glycolysis. Here, respiratory substrate glucose breaks down into two molecules each of pyruvate, ATP and NADH2. Pyruvate is converted into ethyl alcohol (C2H5OH) in Yeast and certain bacteria. It is changed to lactic acid (CH3CHOH.COOH) in muscle cells when oxygen utilisation is faster than its availability as during vigorous exercise. It creates an oxygen debt in the body. No such debt occurs in blood corpuscles.
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 19
(iii) Anaerobic Respiration Producing Lactic Acid:
Build up of lactic acid in muscles during prolonged activity causes fatigue and results in cramps.
Fermentation (L. fermentum-froth). It is anaerobic breakdown of carbohydrates by microorganisms producing alcohol, organic acids and a variety of other products alongwith heat and waste gases. Fermentation is used in brewing industry (for producing wine, whisky, beer), baking industry (for making bread spongy), curd and yoghurt formation, synthesis of vinegar, citric acid, lactic acid, softening and aromatisation of Tobacco, Tea and other beverages, cleaning of hides and separating or retting of fibres (e.g., Jute, Hemp).
NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 20

Question 44.
Describe the flow of blood through heart of human beings.
Answer:
It is passage of the same blood twice through the heart first on the right side, then on the left side in order to complete one cycle. Double circulation has two components, pulmonary circulation and systemic circulation.

  1. Pulmonary Circulation: It is movement of blood from heart to the lungs and back. Deoxygenated blood of the body enters the right auricle, passes into right ventricle which pumps it into pulmonary arch. With the help of two separate pulmonary arteries the blood passes into the lungs. Here, it is oxygenated. Oxygenated blood comes back to left auricle of heart through four pulmonary veins, two from each lung.
  2. Systemic Circulation: It is the circulation of blood between heart and different parts of the body except lungs. Oxygenated blood received by left auricle passes into left ventricle. The left ventricle pumps it into aorta for supply to different body parts including walls of the heart by means of arteries. Inside the organs the blood loses oxygen and nutrients. It picks up carbon dioxide and waste products. This deoxygenated blood is drained by veins and sent to the right auricle of heart.

NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes image - 21

Question 45.
Describe the process of urine formation in kidneys.
Answer:
Mechanism of Urine Formation: 
It has four components — glomerular filtration, selective reabsorption, tubular secretion and concentration.

  1. Glomerular Filtration: Blood flows in glomerulus under pressure due to narrowness of efferent arteriole. As a result it undergoes pressure filtration or ultrafiltration. All small volume solutes (e.g., urea, uric acid, amino acids, hormones, glucose, ions, vitamins) and water are filtered out and enter the Bowman’s capsule. The product is called nephric or glomerular filtrate. Its volume is 125 ml/min (180 litres/day).
  2. Reabsorption: Nephric filtrate is also called primary urine. It passes into proximal convoluted tubule. The peritubular capillaries around PCT reabsorb all the useful components of nephric filtrate, e.g, glucose, amino acids, vitamins C, calcium, potassium, sodium, chloride, bicarbonate and water (75%). Selective reabsorption also occurs in the region of distal convoluted tubule. The amount of water absorption depends upon amount of excess water present in the body and the amount of dissolved waste to be excreted.
  3. Tubular Secretion (Augmentation): It occurs mostly in the distal convoluted tubule which is also surrounded by peritubular capillaries. Smaller amount of tubular secretion also takes place in the area of proximal convoluted tubule. Tubular secretion is active secretion of waste products by the blood capillaries into the urinary tubule. It ensures removal of all the waste products from blood, viz.,’ urea, uric acid, creatinine. Extra salts, K+ and H+ are also secreted into urinary tubule to maintain a proper concentration and pH of the urine.
  4. Concentration of the Urine: 75% of water content of nephric filtrate is reabsorbed in the region of proximal convoluted tubule. Some 10% of water passes out of the filtrate through osmosis in the area of loop of Henle. It is because loops of Henle are immersed in hyper-osmotic interstitial fluid, Further concentration takes place in the area of collecting tubes in the presence of hormone called antidiuretic hormone (ADH) or vasopressin. The hormone is secreted only when concentrated urine is to be passed out. It is not secreted when a person drinks a lot of water. Absence of antidiuretic  hormone produces a dilute urine. Hormone action, therefore, maintains osmotic concentration of body fluids. Deficiency of ADH causes excessive, repeated, dilute urination (diabetes insipidus).

Hope given NCERT Exemplar Solutions for Class 10 Science Chapter 6 Life Processes are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

Value Based Questions in Science for Class 10 Chapter 6 Life Processes

Value Based Questions in Science for Class 10 Chapter 6 Life Processes

These Solutions are part of Value Based Questions in Science for Class 10. Here we have given Value Based Questions in Science for Class 10 Chapter 6 Life Processes

Question 1.
What do we get from environment and what do we give out to environment ? Should we degrade it ?
Answer:
We obtain nutrients, water and oxygen from the environment. In return we give out undigested materials, CO2 and waste products. Environment has been metabolising our wastes for regenerating nutrients and other materials required by us. However, we are producing so many articles for our use which are non-biodegradable. We also generate a lot more garbage, sewage, effluents, polluting gases and particulate matter than the capacity of the environment to metabolise them. They are becoming source of contaminations, infections and disorders. Therefore, we should take immediate measures to stop degrading our environment.

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Question 2.
Two processes are basic to life on earth. What are they ? How do these processes sustain life ?
Answer:
Photosynthesis and respiration are two processes that are basic to life on earth. Without them, life will disappear from earth. Photosynthesis traps solar energy, converts it into chemical energy and manufactures organic matter by reducing CO2. The organic matter produced in photosynthesis not only supports plants but all types of life, helping them in building their body and supplying energy.
Respiration is the process of release of energy from organic matter. This food or chemical energy is essential for maintenance, growth and working of the bodies of the living beings including the plants which trap solar energy.

Question 3.
Soil air is essential for growth and functioning of roots. However, roots do not have pores for exchange of gases. Explain.
Answer:
Roots require a lot of energy for active absorption of minerals and good growth so as to form new root hairs for continued absorption of water. This is possible only with the help of aerobic respiration for which good soil air is required. It should remain connected with atmospheric air for renewal. In soil, exchange of gases occurs at the surface of young roots through diffusion because the external walls of epiblema cells and root hairs are uncutinised. Therefore, despite the absence of pores, roots are always exchanging metabolic gases with the soil air.

Question 4.
In breathing, which ones are active and which ones are passive processes — expansion of thorax, passage of air from outside to lungs and exhalation.
Answer:

  1. Expansion of Thorax: It is an active process which involves contraction of phrenic and external intercostal muscles.
  2. Passage of Air from Outside into Lungs: It is a passive process which occurs due to development of negative pressure in the lungs when they expand with the expansion of thorax.
  3. Exhalation: It is a passive process which occurs due to relaxation of phrenic and external intercostal muscles resulting in contraction of thorax and hence lungs.

Hope given Value Based Questions in Science for Class 10 Chapter 6 Life Processes are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.

HOTS Questions for Class 10 Science Chapter 6 Life Processes

HOTS Questions for Class 10 Science Chapter 6 Life Processes

These Solutions are part of HOTS Questions for Class 10 Science. Here we have given HOTS Questions for Class 10 Science Chapter 6 Life Processes

Question 1.
What does the diagram depict ?
HOTS Questions for Class 10 Science Chapter 6 Life Processes image - 1
Answer:
Gaseous exchange in Amoeba.

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Question 2.
What does diagram depict ? What are A and B ?
HOTS Questions for Class 10 Science Chapter 6 Life Processes image - 2
Answer:
Double Circulation :
(A) Pulmonary Circulation
(B) Systemic Circulation.

Question 3.
How are viruses living when they do not show movements ?
Answer:
Viruses do not show movements outside the host cells. They show movements at the molecular level inside the living cells.

Question 4.
What is
(a) Primary reaction of photosynthesis
(b) Calvin cycle
(c) Krebs cycle
(d) EMP
(e) Oxidative phosphorylation ?
Answer:
(a) Primary Reaction of Photosynthesis: It is the conversion of light energy into chemical energy by chlorophyll a molecules.
(b) Calvin Cycle: It is a cycle of reactions that occur during reduction of CO2 to carbohydrate with the help of ATP and NADPH2 produced during light reaction.
(c) Krebs Cycle: It is a cycle of reactions that occur inside the mitochondria wherein an activated acetyl group is completely oxidised to form CO2, NADH2 and FADH2.
(d) EMP: Embden-Meyerhoff-Parnas pathway, also called glycolysis, is the first step of respiratory breakdown of glucose that occurs in the cytoplasm forming two molecules each of pyruvate, ATP and NADH2.
(e) Oxidative Phosphorylation: It is the process of ATP formation from ADP and inorganic phosphate with the help of energy liberated during oxidation of reduced coenzymes (NADH2, FADH2).

Question 5.
A girdled tree dies if the girdle is wide and is not filled up. Comment.
Answer:
Girdling removes bark containing phloem from the trunk region. Food manufactured by foliage does not reach the roots which requires the same as they are always growing. In the absence of food supply, roots starve and stop absorbing water. The foliage wilts and the plant dies.

Question 6.
Study the diagram. Name the parts “A” and “B”. State one function of each. (CBSE A.I. 2008)
HOTS Questions for Class 10 Science Chapter 6 Life Processes image - 3
Answer:
A—Stomatal pore or stoma Function: Pathway for exchange of gases or photosymthesis and respiration and loss of water vapours in transpiration.
B—Guard cell Function: Two guard cells present in each stoma, create pore when they are turgid and close the same when they are flaccid.

Question 7.
In the experiment “Light is essential for photosynthesis” why does the uncovered part of the leaf turn blue-black after putting iodine solution. (CBSE Foreign 2010)
Answer:
The uncovered part of the leaf exposed to sunlight performs photosynthesis and accumulates starch. Iodine reacts.with starch to give blue-black colouration.

Question 8.
Give one reason why multicellular organisms require special organs for exchange of gases between their body and their environment. (CBSE A.I. 2010)
Answer:
Multicellular organisms require special organs for exchange of gases as most of their cells are internal and are not in direct contact with environment.

Question 9.
Name the green dot like structures in some cells observed by a student when a leaf peel was viewed under a microscope. What is the green colour due to ? (CBSE Delhi 2010)
Answer:
Chloroplasts with green colour due to chlorophyll.

Question 10.
Explain the process of breakdown of glucose in a cell

  1. In the presence of oxygen
  2. In the absence of oxygen. (CBSE foreign 2010)

Answer:
Glucose is first broken down to pyruvic acid during glycolysis. Glycolysis occurs in cell cytoplasm. It produces energy.

  1. Presence of Oxygen: It is aerobic respiration where pyruvic acid is completely oxidised to carbon dioxide and water inside mitochondria releasing a lot of energy.
  2. Absence of Oxygen: Pyruvic acid is metabolised anaerobically in the cell cytoplasm forming either
    1. Ethyl alcohol (ethanol) and carbon dioxide or
    2. lactic acid: Very little energy is released.

Question 11.
Explain the process of digestion of food in mouth, stomach and small intestine in human body. (CBSE Delhi 2010)
Answer:
Mouth: Food is moistened, crushed and acted upon by salivary amylase which converts some starch into maltose and dextrins.
Stomach: Food is acidified, churned and mixed with enzyme pepsin. Pepsin acts in acidic medium over proteins to form soluble components, peptones and proteoses. Small quantities of semi-liquified food called chyme is passed on the duodenum.
Small Intestine: Acidity is neutralised and the food is made alkaline. Food is acted upon by pancreatic juice and succus entericus. Pancreatic juice has trypsin, amylase and lipase enzymes to digest proteins, carbohydrates and fats respectively. Succus entericus has enzymes for breakdown of peptides and disaccharides into amino acids and monosaccharides respectively.

Hope given HOTS Questions for Class 10 Science Chapter 6 Life Processes are helpful to complete your science homework.

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