NCERT Class 11-Biology: Chapter – 12 Mineral Nutrition Part 3 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 13:

Name one non-symbiotic nitrogen fixing prokaryote.


Nitrogen fixing prokaryotes are of two types:

1. Nonsymbiotic nitrogen fixing prokaryote: Azotobacter, Beijernickia etc.

2. Symbiotic nitrogen fixing prokaryote:

Rhodospirilium and Clostridium etc.

Question 14:

Rice fields produce an important green-house gas. Name it.


Rice fields are submerged in water. The bacteria present in the water logged soil under anaerobic conditions produce Methane Gas which is a greenhouse gas.

Question 15:

Complete the equation for reductive amination



Question 16:

Excess of in soil leads to defeciency of and . Justify.


1. Excess of Manganese (Mn) in the soil competes with Ca, Mg and Fe for uptake leading to their deficiency in the plant.

2. Manganese inhibits the translocation of calcium to the root apex hence causing it՚s deficiency.

3. Manganese competes with Magnesium to bind with enzymes hence causing it՚s deficiency.

Short Answer Type Questions

Question 1:

How is sulphur important for plants? Name the aminoacids in which it is present.


Sulphur is present in plants in the form of Sulphate. It is important for plants because:

1. It is important for the formation of Chlorophyll.

2. It is the main constituent of various coenzymes.

3. It is the main constituent of various Vitamins like Thiamine, Coenzyme A and Biotin etc.

4. It is involved in the nodulation of legumes.

5. It is important for the structure of proteins.

Sulphur is present in two Amino acids:

1. Cysteine

2. Methionine

Question 2:

How are organisms like Pseudomonas and Thiobacillus of great significance in nitrogen cycle?


Pseudomonas and Thiobacillus are involved in the process of denitrification during the nitrogen cycle. During denitrification the nitrate present in the soil is converted to free nitrogen thus contributing to presence of nitrogen in the air.

Question 3:

Carefully observe the following figure

Chapter 12 - Question 3 Carefully Observe the Follo …

a. Name the technique shown in the figure and the scientist who demonstrated this technique for the first time.

b. Name atleast three plants for which this technique can be employed for their commercial production.

c. What is the significance of aerating tube and feeding funnel in this setup?


(a) The technique shown in the figure is Hydroponics or Soil less culture of a plant. In this technique the plants are grown in mineral nutrient solution instead of soil.

(b) Tomato, Lettuce, Marijuana, Pepper and Cucumber.

c) Aerating tube: A bent tube used for proper aeration of the medium for growth of roots.

Feeding funnel: It is used for feeding nutrients and water to the medium.