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Multiple Choice
Which component of the cellular respiration pathway is directly inhibited by cyanide?
A
Citric acid cycle (Krebs cycle)
B
Complex IV (cytochrome c oxidase) of the electron transport chain
C
ATP synthase
D
Glycolysis
Verified step by step guidance
1
Understand the role of cyanide in cellular respiration: Cyanide is a potent inhibitor that specifically targets a component of the electron transport chain, disrupting the process of oxidative phosphorylation.
Review the electron transport chain: This pathway is the final stage of cellular respiration, where electrons are transferred through a series of protein complexes embedded in the inner mitochondrial membrane to generate a proton gradient for ATP synthesis.
Identify Complex IV (cytochrome c oxidase): Complex IV is the last protein complex in the electron transport chain. It facilitates the transfer of electrons to oxygen, the final electron acceptor, forming water as a byproduct.
Explain cyanide's mechanism of action: Cyanide binds to the iron within Complex IV, preventing the transfer of electrons to oxygen. This halts the electron transport chain, stopping ATP production and leading to cellular energy failure.
Clarify why other options are incorrect: Cyanide does not directly inhibit glycolysis, the citric acid cycle, or ATP synthase. These processes occur upstream or downstream of the electron transport chain and are not directly affected by cyanide binding.