What is the fate of the NAD\(^+\) newly regenerated by fermentation?

• A. It is broken down into amino acids for protein synthesis.
• B. It is exported out of the cell as a waste product.
• C. It is converted into ATP during oxidative phosphorylation.
• D. It is reused in glycolysis to accept electrons.

Answer: (D)

Verified step by step guidance

1. Understand the role of NAD\(^+\) in cellular respiration: NAD\(^+\) is a coenzyme that acts as an electron carrier during metabolic processes, including glycolysis.
2. Recall the purpose of fermentation: Fermentation occurs in anaerobic conditions to regenerate NAD\(^+\), allowing glycolysis to continue producing ATP in the absence of oxygen.
3. Identify the connection between NAD\(^+\) and glycolysis: NAD\(^+\) is reused in glycolysis to accept electrons from glucose as it is broken down into pyruvate.
4. Eliminate incorrect options: NAD\(^+\) is not broken down into amino acids, exported as waste, or converted into ATP during oxidative phosphorylation (which requires oxygen).
5. Conclude that the regenerated NAD\(^+\) is essential for glycolysis to proceed, ensuring the cell can continue producing ATP anaerobically.