What role does NAD+ play in cellular respiration?

• A. NAD+ is a substrate for ATP synthesis in the electron transport chain.
• B. NAD+ is the final electron acceptor in the electron transport chain.
• C. NAD+ acts as an electron carrier, accepting electrons during glycolysis and the Krebs cycle.
• D. NAD+ provides the energy required for the phosphorylation of ADP to ATP.

Answer: (C)

Verified step by step guidance

1. Understand the role of NAD+ in cellular respiration: NAD+ is a coenzyme that functions as an electron carrier. It is crucial in the process of transferring electrons during metabolic reactions.
2. Recognize the stages of cellular respiration where NAD+ is involved: NAD+ accepts electrons during glycolysis and the Krebs cycle, becoming NADH in the process.
3. Clarify the function of NADH: Once NAD+ has accepted electrons and is converted to NADH, it carries these electrons to the electron transport chain, where they are used to generate ATP.
4. Differentiate NAD+ from other components in the electron transport chain: Unlike the final electron acceptor, which is typically oxygen, NAD+ is involved earlier in the process, primarily in glycolysis and the Krebs cycle.
5. Summarize the importance of NAD+ in energy production: By acting as an electron carrier, NAD+ plays a vital role in the conversion of energy from nutrients into ATP, the energy currency of the cell.