Question

which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?

the citric acid cycle
the electron transport chain
glycolysis
reduction of pyruvate to lactate

Explanation:

Glycolysis is the first stage of glucose metabolism. It occurs in the cytoplasm. In cellular respiration (aerobic), after glycolysis, pyruvate enters the mitochondria for the citric acid cycle and electron transport chain. In fermentation (anaerobic), after glycolysis, pyruvate is further processed (e.g., reduced to lactate in lactic acid fermentation). The citric acid cycle and electron transport chain are only in aerobic cellular respiration. Reduction of pyruvate to lactate is specific to lactic acid fermentation.

Answer:

glycolysis