Q35 / 200 · MHT CET - Medical 2026 (23 April Shift 1) · Biology
How many electrons and ATP are required for the biological fixation of a molecule of nitrogen to form ammonia?
- A4 and 8 respectively
- B2 and 4 respectively
- Correct answerC8 and 16 respectively
- D16 and 32 respectively
Solution
The biological nitrogen fixation is catalyzed by the enzyme nitrogenase. The overall reaction for the reduction of one molecule of nitrogen ($N_2$) to two molecules of ammonia ($NH_3$) is given by:
$N_2 + 8e^- + 8H^+ + 16ATP \rightarrow 2NH_3 + H_2 + 16ADP + 16P_i$
From the balanced equation, the fixation of one molecule of nitrogen requires $8$ electrons and $16$ ATP molecules.
Answer: 8 and 16 respectively
$N_2 + 8e^- + 8H^+ + 16ATP \rightarrow 2NH_3 + H_2 + 16ADP + 16P_i$
From the balanced equation, the fixation of one molecule of nitrogen requires $8$ electrons and $16$ ATP molecules.
Answer: 8 and 16 respectively
Hence, the correct answer is option: 'C'.