Question

The process of nitrogen-fixation by bacteria does not take place in the presence of

Options

• the molecular form of hydrogen

• the elemental form of oxygen

• water

• the elemental form of nitrogen

Answer 1

the elemental form of oxygen

Explanation:

Nitrogen fixation is the conversion of inert atmosphere nitrogen or dinitrogen (N2) into utilisable compounds of nitrate, ammonia, amino acids. Various bacteria like Rhizobium and Azotobacter convert the atmospheric nitrogen into water-soluble nitrates. The nitrogenase enzyme is a prime requirement for biological nitrogen fixation. This enzyme is vulnerable to oxygen and gets destroyed in its presence. It is due to this reason, that most nitrogen-fixing bacteria live in anaerobic conditions or sequester oxygen with the proteins like leghaemoglobin.