CBSE Class 11th Biology Notes for Chapter 12 Mineral Nutrition

Chapter 12 Mineral Nutrition
 
MACRONUTRIENTS
Macronutrients are generally present in plant tissues in large amounts. These macronutrients include carbon, hydrogen, oxygen, nitrogen, phosphorous, sulphur, potassium, calcium and magnesium.
MICRONUTRIENTS
Micronutrients or trace elements are needed in very small amounts. These include iron, manganese, copper, molybdenum, zinc, boron, chlorine and nickel.
 
Essential elements can be grouped into four broad categories on the basis of their diverse functions:

1. Essential elements as components of biomolecules
2. Essential elements that are components of energy related chemical compounds in plants.
3. Essential elements that activate or inhibit enzymes.
4. Some essential elements can alter the osmotic potential of a cell.

 
ROLE OF MACRO- AND MICRO-NUTRIENTS

1. Nitrogen: Required by all parts of the plant. It is one of the major constituents of proteins, nucleic acids, vitamins and hormones.
2. Phosphorus: Phosphorus is a constituent of cell membranes , certain proteins, all nucleic acids and nucleotides, and is required for all phosphorylation reactions.
3. Potassium: It helps to maintain an anion-cation balance in cells and is involved in protein synthesis, opening and closing of stomata, activation of enzymes and in the maintenance of the turgidity of cells.
4. Calcium: It is required during cell division in the synthesis of cell wall.
5. Magnesium: It activates the enzymes of respiration, photosynthesis and is involved in the synthesis of DNA and RNA.
6. Sulphur: It is present in two amino acids- cysteine and methionine and is the main constituent of several coenzymes, vitamins.
7. Iron: It activates catalase enzymes and is essential for the formation of chlorophyll.
8. Manganese: It helps in splitting of water to liberate oxygen during photosynthesis.
9. Zinc: It activates various enzymes. It also needed in the synthesis of auxin.
10. Copper: It is essential for the overall metabolism in plants.
11. Boron: It is requires for uptake and utilization of calcium, membrane functioning, pollen germination, cell elongation, cell differentiation and carbohydrate translocation.
12. Molybdenum: It is component of several enzymes.
13. Chlorine: It is essential for the water splitting reaction in photosynthesis.