What role does oxygen play in aerobic cellular respiration?

• A. Oxygen is converted into ATP during the Krebs cycle.
• B. Oxygen is a substrate for the enzyme hexokinase.
• C. Oxygen is used to break down glucose during glycolysis.
• D. Oxygen acts as the final electron acceptor in the electron transport chain.

Answer: (D)

Verified step by step guidance

1. Begin by understanding the process of aerobic cellular respiration, which consists of glycolysis, the Krebs cycle, and the electron transport chain.
2. Recognize that oxygen is not directly involved in glycolysis or the Krebs cycle. Glycolysis occurs in the cytoplasm and does not require oxygen, while the Krebs cycle occurs in the mitochondria and produces electron carriers for the electron transport chain.
3. Identify the role of oxygen in the electron transport chain, which is the final stage of aerobic respiration. This chain is located in the inner mitochondrial membrane.
4. Understand that during the electron transport chain, electrons are transferred through a series of proteins and ultimately to oxygen, which acts as the final electron acceptor.
5. Learn that when oxygen accepts electrons, it combines with protons to form water, a crucial step that allows the electron transport chain to continue functioning and produce ATP efficiently.