What occurs to NADH during lactic acid fermentation in animals?

During lactic acid fermentation in animals, NADH plays a crucial role in the regeneration of NAD+. This process is essential because NAD+ is needed for glycolysis to continue. In the absence of oxygen, cells must rely on fermentation to keep producing ATP. As glucose is broken down, NAD+ is reduced to NADH, but for glycolysis to persist, NADH must be converted back into NAD+.

During lactic acid fermentation, NADH donates its electrons to the pyruvate generated from glycolysis, resulting in the formation of lactic acid and regenerating NAD+. This allows glycolysis to continue producing a small amount of ATP without the presence of oxygen. Therefore, the conversion of NADH into NAD+ is a vital step that enables the continued functioning of metabolic processes in anaerobic conditions.