Question

In tissues deriving energy anaerobically (such as rapidly exercising skeletal muscle), lactate, rather than pyruvate, serves as the end product of glycolysis.
Which of the following statements best explains why pyruvate is converted to lactate under these circumstances?
A. The mitochondrion is more permeable to lactate than to pyruvate.
B. Lactate, but not pyruvate, serves as a substrate for gluconeogenesis.
C. The conversion of pyruvate to lactate is accompanied by the production of ATP.
D. NAD+ necessary for the glyceraldehyde phosphate dehydrogenase reaction is regenerated

Answer 1

Answer: Option D

pyruvate is converted to lactate when NAD+ necessary for glyceraldehyde phosphate dehydrogenase reaction is regenerated in glycolysis.

Explanation:

Anaerobic glycolysis is the conversion of glucose to lactate in muscles cells when there is limited supply of oxygen.

When there is not enough oxygen in the muscle cells for oxidation of pyruvate to NADH(nicotinamide adenine dinuleotide hydrogen) produced in glycolysis, NAD+ (nicotinamide adenine dinucleotide) which is important for glyceraldehyde phosphate dehydrogenase is regenerated from NADH by reduction of pyruvate to lactate.