In the absence of oxygen, fermentation:

Question

Quizplus · Accepted Answer

In the absence of oxygen, pyruvate is not oxidized by the electron transport chain, so NADH cannot be oxidized to recharge NAD+ for glycolysis to continue. Instead, pyruvate is converted to either lactate or ethanol (depending on the organism) through fermentation, which regenerates NAD+ to keep glycolysis going. Regenerating NAD+ is accomplished through the reduction of pyruvate, which converts NAD+ to NADH. This is option A.

In the Absence of Oxygen, Fermentation