Question

1. Where is nitrogen found in living organisms?
2. How do living organisms uptake nitrogen?
3. What percentage of the atmosphere is nitrogen?
4. Describe the nitrogen fixation process. Be sure to include nitrate, nitrogen gas, nitrite, and ammonium.
5. What is assimilation?

Answer 1

Nitrogen is found in living organisms like plants and animals which body's constituents are made up of amino acids, Nucleic acids, proteins in which nitrogen is present. So all these are types of components in which nitrogen is present in living organisms. It also constitutes several organic and inorganic materials as well.

Living organisms like plants take up Nitrogen from the soil and accumulates nitrogen in themselves. Animals eat these plants and proteinous compounds to obtain nitrogen.

There is about 75-78% nitrogen present in the atmosphere.

Nitrogen fixation process- This is the process by which the atmospheric nitrogen present in the air is converted into ammonia or any other nitrogenous compound. Nitrogenous compounds could be ammonium, nitrites, nitrates etc. Nitrogen gas from the atmosphere is fixed into ammonia in the plants with the help of microorganisms like Rhizobium . Now there are certain nitrogen fixing bacteria present in the soil. Once nitrogen is converted into ammonium ions it is changed into nitrites by nitrification and further into nitrates with the help of nitrifying bacterias.Now some of these nitrates get assimilated into the plants. While several form of nitrates goes back into form of N2 gas with the help of denitrifying bacterias. also decomposers like bacteria and fungi also fix ammonium ions into the soil.

Assimilation is the process by which plants and animals are able to convert assimilated nitrates in form of amino acids in their body. Incorporating nitrogenous substances in the available reduced form is termed as assimilation.Nitrates are available from the process of nitrification and nitrogen fixation.

If you like my answer please upvote.