During cellular respiration, which molecule acts as the final electron acceptor in the electron transport chain?

• A. NADH
• B. Glucose (\(C_6H_{12}O_6\))
• C. Oxygen (\(O_2\))
• D. Carbon dioxide (\(CO_2\))

Answer: (C)

Verified step by step guidance

1. Understand the concept of the electron transport chain: It is the final stage of cellular respiration, where electrons are transferred through a series of protein complexes embedded in the inner mitochondrial membrane.
2. Recognize the role of electron carriers: NADH and FADH₂ donate electrons to the electron transport chain, which are passed along the chain to generate a proton gradient.
3. Identify the final electron acceptor: At the end of the electron transport chain, the electrons must be accepted by a molecule to prevent a backup in the chain. This molecule is oxygen (\(O_2\)).
4. Explain why oxygen (\(O_2\)) is the final electron acceptor: Oxygen combines with electrons and protons to form water (\(H_2O\)), which is a crucial step in maintaining the flow of electrons and ensuring the continuation of ATP production.
5. Clarify why other options are incorrect: NADH and glucose (\(C_6H_{12}O_6\)) are electron donors, not acceptors. Carbon dioxide (\(CO_2\)) is a byproduct of cellular respiration, not involved in the electron transport chain as an acceptor.