Question

Choose the forms in which most plants absorb nitrogen (i) Proteins (ii) Nitrates and Nitrites (iii) Urea (iv) Atmospheric nitrogen. Choose.

• A. (i) and (ii)
• B. (ii) and (iii)
• C. (iii) and (iv)
• D. (i) and (iv)

Answer 1

The correct option is B

(ii) and (iii)

The correct option is B.

Explanation of the correct option:

1. Nitrogen fixation is the process of converting gaseous di-nitrogen into inorganic nitrogenous compounds. There are two ways to do it.
2. The abiological approach happens when UV radiation and lightning convert di-nitrogen to nitric oxide, which is then oxidized to nitrogen dioxide in the atmosphere.
3. These oxides dissolve in rains and become nitrous and nitric acid in the soil.
4. These acids react with the soil's alkali radicals to generate nitrates.
5. Plants are able to absorb soluble nitrates directly. Biological nitrogen fixation is a biological technique that includes prokaryotes converting di-nitrogen into nitrogenous molecules. The process of absorbing nitrates and ammonia to form organic nitrogen is known as nitrogen absorption.

Explanation of the incorrect options:

Option A:

1. Plants are unable to utilize complex proteins. The biological approach takes place in the atmosphere, where UV rays and lighting convert dinitrogen to nitric oxide, which is then oxidized to nitrogen dioxide.
2. These oxides dissolve in rainwater and become nitrous and nitric acid in the soil.
3. These acids react with the soil's alkali radicals to generate nitrates. Plants take soluble nitrates immediately.

Option C:

1. Complex proteins cannot be used by plants. In the biological approach, UV rays and illumination convert dinitrogen to nitric oxide, which is then oxidised to nitrogen dioxide in the environment.
2. These oxides dissolve in rains and decompose in the soil to form nitrous and nitric acid. Nitrates are formed when these acids react with the alkali radicals in the soil. Soluble nitrates are quickly absorbed by plants.

Option D:

1. Complex proteins can't be used by plants. UV rays and lights convert dinitrogen to nitric oxide, which is subsequently oxidised to nitrogen dioxide, in the biological way.
2. In the soil, these oxides dissolve in rains and turn into nitrous and nitric acid. Nitrates are formed when these acids combine with alkali radicals in the soil. Soluble nitrates are absorbed quickly by plants.

Final answer: the correct option is B.