NDA General Ability Question (2025) — Solution

Step-by-step solution

During rigorous exercise, the demand for energy in muscle cells is high, but the supply of oxygen is limited. Under these anaerobic conditions, glucose is first broken down into pyruvate through glycolysis in the cytoplasm. To regenerate NAD^+ for glycolysis to continue, pyruvate is reduced to lactic acid by the enzyme lactate dehydrogenase. Thus, the lactic acid that accumulates in muscle cells and causes cramps is directly produced from pyruvate. Answer: Pyruvate