Question

Nitrogen fixing bacteria converts

• A. N${}_2$ $⟶$ NH${}_3$
• B. NH${}_4^{+}$ $⟶$ Nitrates
• C. NO${}_2$ $⟶$ NO${}_3$
• D. NO${}_3$ $⟶$ N${}_2$

Answer 1

The correct option is A N${}_2$ $⟶$ NH${}_3$

• Conversion of atmospheric inert nitrogen into usable ammonia is termed as nitrogen fixation which is carried out by free-living symbiotic bacteria.
• They have a multisubunit enzyme complex, nitrogenase, which catalyzes the reduction of nitrogen to ammonia. The oxidation of ammonia (NH${}_4$) to nitrite (NO${}_2^{-}$) and finally to nitrate (NO${}_3^{-}$) is called as nitrification. It is carried out by nitrifying bacteria.
• Nitrifier bacteria, Nitrobacter and Nitrococcus, convert nitrite into nitrate. Denitrification bacteria carry out the final step in returning nitrogen back to the atmospheric reservoir. They reduce the nitrates into nitrogen.

Thus, the correct answer is option A.