Correct Response: D. Fermentation is a process cells use to deal with the products of glycolysis in the absence of oxygen. During glycolysis, NAD+ is reduced to NADH in order to produce ATP and pyruvate. The cell needs to regenerate NAD+ so that glycolysis can continue. Under anaerobic conditions, fermentation occurs. Pyruvate is reduced to lactic acid, and NADH is oxidized to regenerate NAD+. Hydrolysis (A) is a general term that refers to reactions in which water is used to split a larger molecule. These reactions generally do not produce lactic acid. Glycolysis (C) itself does not produce lactic acid. Rather, under aerobic conditions, the NADH and pyruvate generated during glycolysis are shuttled into the mitochondria, which uses them to produce more ATP via the process of cellular respiration (B). Lactic acid is not a byproduct of cellular respiration.
