You discover a metabolic poison called PSN1 that kills insects, and decide to test whether this poison affects the electron transport chain. In the mitochondria of insects treated with PSN1, most molecules of cytochrome c and complex IV are oxidized, while most of complex III and coenzyme Q are reduced. Oxygen consumption in such mitochondria is decreased dramatically. Which of the following is the best possible explanation for the activity of PSN1? a. PSN1 is an ETC decoupler, permitting hydrogen ions to pass through the membrane.
b. PSN1 is a molecular mimic of oxygen, competing for the active site of complex IV.
c. PSN1 irreversibly binds to coenzyme Q, preventing its oxidation.
d. PSN1 is an inhibitor of cytochrome c, preventing its reduction.