2026 · Q95
Which one of the following statements about the catalytic conversion of nitrogen gas by nitrogenase enzyme in root nodules of leguminous plants is not correct?
general-sciencebiology-plants
- AIt needs ATP (Adenosine Tri-Phosphate) supply.
- BIt converts N2 (nitrogen gas) to NH4+ (ammonium ion) first.
- CIt needs hydrogen supply from reduced NADP (Nicotinamide Adenine Dinucleotide Phosphate).
- DIt needs aerobic condition for the process.
Explanation
Nitrogenase-mediated nitrogen fixation needs a large ATP supply (about 16 ATP per N₂) and uses reduced ferredoxin/NADPH as the electron/hydrogen donor, converting N₂ to ammonia/ammonium — so A, B and C are correct. But nitrogenase is irreversibly inactivated by oxygen; root nodules maintain microaerobic conditions using leghemoglobin. Option D's claim that it needs aerobic conditions is therefore not correct.