Discuss the nitrogen cycle in nature? (5)
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Answer:
Terms involved in nitrogen cycle are
1. Nitrogen fixation : Plants cannot use free nitrogen present in the air. This nitrogen molecule is converted into nitrates and nitrites which can be taken up and used to make the required molceule. This is called nitrogen fixation which can be done by the bacterias that live in the root nodules of leguminors plants. By physical process during lightning, the high temperatures and pressures is created in the air which convert nitrogen into oxides of nitrogen and dissolve in water and come down along with rain. This is also called nitrification.
2. Ammonification. The nitrogen compounds formed are taken by plants to form proteins which are further converted into ammonia.
3. Denitrification. The nitrates and nitrites of nitrogen are acted upon by other group of microbes e.g. Pseudomonas bacteria,which convert these compounds into free nitrogen gas.
Nitrogen cycle:
1. Free nitrogen from atmosphere is converted into nitrates by bacterias or by lightning.
2. Nitrates mix with soil, is absorbed by the plants to make proteins.
3. The proteins in plants and animals are converted into amino acids and ammonia.
4. Ammonia is converted into nitrates nitrates and then these nitrates and nitrites present in soil is acted up on by other group of bacterias called denitrifying bacteria. The process is called denitrification, nitrates are converted into free nitrogen and is released back to the atmosphere.