Question

Select the enzyme complex responsible for biological nitrogen fixation?

• A. Nitrate reductase
• B. Nitrogenase
• C. Nitrite reductase
• D. Glutamine synthetase

Hint:

Nitrogen fixation reaction: \[ \boxed{ N_2+8H^++8e^-+16ATP \longrightarrow 2NH_3+H_2+16ADP+16P_i } \] The enzyme responsible is \[ \boxed{\text{Nitrogenase}.} \]

Answer 1

The Correct Option is B

Step 1: Recall the enzyme involved in nitrogen fixation. Biological nitrogen fixation is the conversion of atmospheric nitrogen \[ N_2 \] into ammonia \[ NH_3. \] This reaction is catalyzed by the enzyme complex \[ \boxed{\text{Nitrogenase}.} \]

Step 2: Identify the correct enzyme. Nitrogenase consists of
• Fe-protein (Iron protein),
• MoFe-protein (Molybdenum-Iron protein). It catalyzes the reduction of atmospheric nitrogen to ammonia. Hence, \[ \boxed{\text{Nitrogenase}} \] is the correct answer. Therefore, \[ \boxed{(B)} \] is the correct answer.