Oxidative phosphorylation is inhibited by all EXCEPT:
**Core Concept**
Oxidative phosphorylation is a crucial cellular process responsible for generating ATP in the mitochondria. It involves the transfer of electrons through a series of electron transport chains, resulting in the pumping of protons across the mitochondrial membrane and the subsequent production of ATP through chemiosmosis.
**Why the Correct Answer is Right**
The electron transport chains in oxidative phosphorylation are sensitive to various inhibitors that can block the transfer of electrons or the pumping of protons. The correct answer is an inhibitor that does not affect oxidative phosphorylation.
*Option A: Antimycin A* is a potent inhibitor of the electron transport chain, specifically targeting Complex III (cytochrome b-c1 complex). It blocks the transfer of electrons from cytochrome b to cytochrome c1, thereby inhibiting the electron transport chain.
*Option B: Cyanide* is a potent inhibitor of Complex IV (cytochrome c oxidase) of the electron transport chain. It binds to the iron atom in the cytochrome c oxidase, preventing the transfer of electrons and inhibiting oxidative phosphorylation.
*Option C: Oligomycin* is an inhibitor of the F1F0-ATP synthase, which is responsible for generating ATP from ADP and Pi during oxidative phosphorylation. It blocks the production of ATP by inhibiting the rotation of the stalk subunit, which is essential for the synthesis of ATP.
**Why Each Wrong Option is Incorrect**
*Option D: Rotenone* is actually an inhibitor of Complex I (NADH dehydrogenase) of the electron transport chain. It blocks the transfer of electrons from NADH to ubiquinone, thereby inhibiting oxidative phosphorylation. This makes it a correct answer, not an exception.
**Clinical Pearl / High-Yield Fact**
Rotenone is a potent insecticide that can also inhibit Complex I of the electron transport chain, making it a useful tool in the laboratory for studying oxidative phosphorylation.
**Correct Answer: D. Rotenone**