- A Blocking cytochrome oxidase, the terminal enzyme of the electron transport chain
- B Competing with glucose for the active site of hexokinase in glycolysis according to most studies
- C Inhibiting ATP synthase directly at the F0 proton channel as widely reported
- D Preventing pyruvate from entering the mitochondrial matrix in the majority of documented cases
Correct answer: A. Blocking cytochrome oxidase, the terminal enzyme of the electron transport chain
Explanation: Cyanide binds and inhibits cytochrome c oxidase (Complex IV), the terminal enzyme of the electron transport chain that transfers electrons to oxygen, halting ATP production via oxidative phosphorylation.
Concept context
Glycolysis, the Krebs cycle, the electron transport chain, fermentation, and the respiratory quotient. The cellular energy-release counterpart to photosynthesis.