Glycogen is converted to lactic acid during which physiological state?

• A. While living
• B. At death
• C. During decomposition
• D. After burial

Answer: (A)

Glycogen to lactic acid occurs when cells run glycolysis under low oxygen, which happens during intense exercise or any situation where oxygen delivery to muscles is insufficient. In this anaerobic state, glycogen in muscle is broken down to glucose-6-phosphate and enters glycolysis. Because there isn’t enough oxygen for oxidative phosphorylation, the end product pyruvate is reduced to lactate by lactate dehydrogenase, regenerating NAD+ so glycolysis can continue and ATP can be produced quickly. This lactate buildup reflects the body's attempt to keep energy production going despite limited oxygen.

The other states don’t fit because they involve nonliving processes or different pathways: after death or during decomposition and burial, cellular metabolism ceases or shifts to microbial breakdown, so the controlled conversion of glycogen to lactic acid by living muscle cells doesn’t occur.