Cyanide stops the production of ATP. Which of the following processes would be directly affected by cyanide?

• A. Fermentation
• B. Krebs Cycle
• C. Glycolysis
• D. Electron Transport Chain

Answer: (D)

Verified step by step guidance

1. Understand that ATP (adenosine triphosphate) is the primary energy carrier in cells, and its production is crucial for cellular functions.
2. Recognize that cyanide is a potent inhibitor of the electron transport chain, which is the final stage of cellular respiration occurring in the mitochondria.
3. Recall that the electron transport chain is responsible for the majority of ATP production in aerobic respiration by using electrons from NADH and FADH2 to pump protons across the mitochondrial membrane, creating a gradient.
4. Identify that the electron transport chain is directly affected by cyanide because it inhibits cytochrome c oxidase, a key enzyme in the chain, preventing electron transfer and halting ATP synthesis.
5. Conclude that while fermentation, the Krebs cycle, and glycolysis are parts of cellular respiration, the electron transport chain is the process directly affected by cyanide, as it stops ATP production by blocking the final step of electron transfer.