Why do vigorously exercising muscle cells convert pyruvate to lactate when oxygen is limited?
Answer and explanation
Correct answer: B. To regenerate NAD+ so that glycolysis can keep producing a little ATP
- Step 1: Glycolysis needs NAD+ to continue. Step 2. Without oxygen the electron transport chain cannot reoxidise NADH. Step 3. Lactate formation reoxidises NADH to NAD+. Answer: to regenerate NAD+. Why not the others: fermentation gives far less ATP than aerobic respiration, lactate does not remove carbon dioxide, and it is not a lipid store.
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