Question:medium
NADH-CoQ reductase is inhibited by?
NADH-CoQ reductase is inhibited by?
Show Hint
Which insecticide is the classic Complex I blocker?
Updated On: Jun 24, 2026
- Rotenone
- Carbon monoxide
- Antimycin
- Atractyloside
Show Solution
The Correct Option is A
Solution and Explanation
Step 1: The respiratory chain has four complexes. The question targets Complex I, the NADH to coenzyme Q reductase.
Step 2: Sorting the options by their site of action makes the answer clear. Carbon monoxide poisons Complex IV by blocking cytochrome aa3 to oxygen, antimycin A blocks Complex III between cytochrome b and c1, and atractyloside acts on the adenine nucleotide translocase that moves ADP into the mitochondrion.
Step 3: Rotenone is the agent that specifically halts electron transfer at Complex I, stopping the hand-off from the iron-sulfur centers to coenzyme Q.
Step 4: Therefore the inhibitor of NADH-CoQ reductase is rotenone.
\[\boxed{\text{Rotenone}}\]
Step 2: Sorting the options by their site of action makes the answer clear. Carbon monoxide poisons Complex IV by blocking cytochrome aa3 to oxygen, antimycin A blocks Complex III between cytochrome b and c1, and atractyloside acts on the adenine nucleotide translocase that moves ADP into the mitochondrion.
Step 3: Rotenone is the agent that specifically halts electron transfer at Complex I, stopping the hand-off from the iron-sulfur centers to coenzyme Q.
Step 4: Therefore the inhibitor of NADH-CoQ reductase is rotenone.
\[\boxed{\text{Rotenone}}\]
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