Write a note on nitrogen fixation?

The conversion of atmospheric nitrogen into ammonia NH3 is known as nitrogen fixation. Bacteria that perform nitrogen fixation are either free living or they may form symbiotic associations with other organisms.

Eg- protozoans, termites. Through the process of nitrogen fixation, free nitrogen of air is converted into ammonia and nitrate, which is taken up by plants. In plants, nitrate is converted into amino acids, nucleotides, proteins, and other nitrogenous compounds.