What is the ultimate electron acceptor in the mitochondrial electron transport chain during aerobic cellular respiration?
Answer and explanation
Correct answer: A. Molecular oxygen
- Step 1: Complex IV (cytochrome c oxidase) transfers four electrons to molecular oxygen (O2) and combines them with four protons to form two water molecules. Step 2. Without oxygen to accept electrons, the electron transport chain halts and oxidative phosphorylation ceases. Answer: Molecular oxygen. Why not the others: NAD+ and FAD are electron carriers that deliver electrons from the Krebs cycle; cytochrome c is an intermediate mobile electron carrier.
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