Which energy source provides high yields of ATP necessary for prolonged-duration exercise?

• A. Oxidative phosphorylation
• B. Glycolysis
• C. Fermentation
• D. Substrate-level phosphorylation

Answer: (A)

Verified step by step guidance

1. Understand the context: The question is about energy sources that provide ATP for prolonged-duration exercise. ATP (adenosine triphosphate) is the energy currency of the cell, and different processes generate ATP in varying amounts and durations.
2. Identify the processes: The options given are oxidative phosphorylation, glycolysis, fermentation, and substrate-level phosphorylation. Each of these processes contributes to ATP production in different ways.
3. Oxidative phosphorylation: This process occurs in the mitochondria and involves the electron transport chain and chemiosmosis. It is highly efficient and produces a large amount of ATP, making it suitable for prolonged exercise.
4. Glycolysis: This is the breakdown of glucose into pyruvate, producing a small amount of ATP quickly. It is anaerobic and not as efficient as oxidative phosphorylation for long-term energy needs.
5. Fermentation and substrate-level phosphorylation: Fermentation is an anaerobic process that allows glycolysis to continue by regenerating NAD+, but it does not produce additional ATP. Substrate-level phosphorylation occurs during glycolysis and the Krebs cycle, producing ATP directly but in smaller amounts compared to oxidative phosphorylation.