Question

and labelled diagram to illustrate nitrogen cycle mention the main steps involved in this process​

Answer 1

the various steps are nitrification denitrification and ammonification

Answer 2

Nitrogen Cycle

Nitrogen is a vital element. It is a part of most of the cellular components like proteins, nucleic acids (DNA and RNA), vitamins, etc. It is also a major constituent of chlorophyll in plants. Plants obtain their nitrogen from the soil while animals obtain it from plants. A cycle of processes helps in maintaining the concentration of nitrogen in the atmosphere and meet the requirement of every organism. This cycle of nitrogen is called the nitrogen cycle.

The nitrogen cycle is the recycling and reusing of nitrogen in different forms to meet the demand for various environmental activities. This happens through various processes with the help of certain microorganisms. In the atmosphere, nitrogen is available in a diatomic form i.e. N2. Plants and certain organisms can’t use nitrogen in this form. Therefore N2 is converted into nitrogen oxides like NO, NO2, NO3. Various processes like lightning; industrial combustion, forest fire etc. contribute to these oxides.

PROCESS OF NITROGEN CYCLE

Ammonification: Ammonia is obtained from dead and decaying plants and animals by decomposition. This process is called ammonification.

Nitrification: In this step, ammonia obtained is first converted to nitrite (NO2) by bacteria like Nitrosomonas, Nitrococcus, etc. and then to nitrate (NO3) by Nitrobacterium. Bacteria involved in nitrification are called chemoautotrophs.  Here is the reaction involved in the process of Nitrification.

2 NH3 + 3O2 ―→ 2NO2– + 2H+ + 2H2O

2NO2– + O2 ―→ 2NO3–