By going through these CBSE Class 11 Biology Notes Chapter 12 Mineral Nutrition, students can recall all the concepts quickly.
Mineral Nutrition Notes Class 11 Biology Chapter 12
→ Plants obtain their inorganic nutrients from the air, water, and soil. Plants absorb a wide variety of mineral elements.
→ Not all the mineral elements that they absorb are required by plants. Out of the more than 105 elements discovered so far, less than 21 are essential and beneficial for normal plant growth and development.
→ The elements required in large quantities are called micronutrients while those required in fewer quantities or in the trace are termed as micro¬nutrients.
→ These elements are either essential constituents of proteins, carbohydrates. fats, nucleic acid, etc., and/or take part in various metabolic processes.
→ Deficiency of each of these essential elements may lead to symptoms called deficiency symptoms.
→ Chlorosis, necrosis, stunted growth, impaired cell division, etc. are some prominent deficiency symptoms.
→ Plants absorb minerals through roots by either passive or active processes. They are carried to all parts of the organism through xylem along with water transport.
→ Nitrogen is very essential for the sustenance of life.
→ Plants cannot use atmospheric nitrogen directly. But some of the plants, especially roots of legumes, can fix this atmospheric nitrogen into biologically usable forms.
→ Nitrogen fixation requires a strong reducing agent and energy in the form of ATP. N, fixation is accomplished with the help of nitrogen-fixing microbes, mainly Rhizobium.
→ The enzyme dinitrogenase which plays an important role in bio-logical N, fixation is very sensitive to oxygen.
→ Most of the processes take place in an anaerobic environment.
→ The energy, ATP. required is provided by the aerobic respiration of the host cells.
→ Ammonia produced following N. fixation is incorporated into amino acid as the amino group.
→ Transamination: It involves the transfer of an amino group from one amino acid to the keto group of a keto acid. Glutamic acid is the main amino acid from which the transfer of H2 the amino group takes place and other amino acids are formed through transamination. The enzyme transaminase catalyzes all such reactions.
→ Leghaemoglobin: The nodules have adaptations that ensure that the enzyme is protected from oxygen. To protect these enzymes, the nodule contains an oxygen scavenger called leghaemoglobin.
→ Nitrification: Ammonia is first oxidized to nitrite by the bacteria Nitrosomonas and/or Enterococcus. The nitrite is further oxidized to nitrate with the help of the bacterium Nitrobacter. These steps are called nitri¬fication.
→ Critical concentration: The concentration of the essential element below which plant growth is retarded is termed as critical concentration.