Biological nitrogen fixation is energetically expensive. Assuming that NADPH is used as the reducing equivalent, how many ATPs are used in the enzymatic conversion of N₂ to NH₃?
A) 16
B) 32
C) 48
D) 64
E) none; only GTP is used

Question

Quizplus · Accepted Answer

The enzymatic conversion of N₂ to NH₃ (ammonia) by the nitrogenase complex requires 16 ATP molecules for each N₂ molecule reduced. This process is energetically expensive because it involves the breaking of the triple bond in N₂, which is a very stable molecule.

Biological Nitrogen Fixation Is Energetically Expensive