Concept 5 Review: Alcoholic Fermentation
In alcoholic fermentation, the pyruvic acid from glycolysis loses one carbon in the form of carbon dioxide to form acetaldehyde, which is reduced to ethyl alcohol by NADH. When acetaldehyde is reduced to ethyl alcohol, NADH becomes NAD+ (is oxidized). This is the fermentation that commonly occurs in yeast. Like lactic acid fermentation, alcoholic fermentation allows glycolysis to continue by ensuring that NADH is returned to its oxidized state (NAD+).