Question

Describe two obstacles that makes fixing atmospheric nitrogen difficult.

Answer 1

Nitrogen fixation = The conversion of molecular nitrogen to usable forms such as nitrite, nitrate or ammonia
Nitrogen fixation is a difficult process due to the following reasons.
i. The usable forms of nitrogen contain a single nitrogen atom. However, the molecular nitrogen contains two nitrogen atoms held together by three covalent bonds. Nitrogen is one of the most stable and inert molecules. It requires a great amount of energy to convert it to the usable forms.
ii. Biological nitrogen fixation utilizes an enzyme complex known as Nitrogenase complex. Nitrogenase complex is found only in prokaryotes. So, only bacteria and archaea can fix atmospheric nitrogen.
iii. Nitrogen is an oxygen-sensitive enzyme i.e. it is no-functional in the presence of oxygen. Hence, strict anaerobic conditions have to be provided for the nitrogenase to be functional.