Rotenone and succinate oxidation
Isolated mitochondria treated with rotenone, a complex I inhibitor, are given succinate. What happens?
Answer D: explanation for every choice
A
Only electrons from NADH are blocked.
B
Oxidative phosphorylation needs electron flow to oxygen to maintain the gradient.
C
Electron flow through complexes III and IV still pumps protons for ATP synthase.
D
Correct. Succinate dehydrogenase passes electrons to ubiquinone via FADH2, bypassing complex I. Complexes III and IV still pump protons.
TakeawayRotenone blocks NADH-linked substrates. Succinate enters at complex II and bypasses it.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb160.