Question

Which of these are respiratory poisons or inhibitors of ETC?

• A. Cyanides
• B. Antimycin A
• C. Carbon monoxide
• D. All of these

Answer 1

Answer: (D)

Site-specific inhibitors of electron transport prevent the passage of electrons by binding to a component of the chain, blocking the oxidation/reduction reaction. Antimycin $A$, an antibiotic, blocks electron transport at the level of the $CoQ{H}_2$ -cytochrome $c$ -reductase (Complex III). Cyanide, azide and $CO$ bind with cytochrome oxidase complex and inhibit the terminal transfer of electrons to oxygen.