How many NADH molecules are produced during glycolysis?

During glycolysis, two molecules of NADH are produced. This process occurs when glucose, a six-carbon sugar, undergoes a series of enzymatic reactions to ultimately form pyruvate, a three-carbon compound. Specifically, in the energy investment phase, glucose is phosphorylated and then cleaved into two three-carbon molecules. During the energy payoff phase, these three-carbon molecules are further processed.

The key step involving NADH production occurs when glyceraldehyde-3-phosphate is oxidized and phosphorylated. This reaction is catalyzed by the enzyme glyceraldehyde-3-phosphate dehydrogenase, where NAD+ is reduced to NADH. Since there are two molecules of glyceraldehyde-3-phosphate produced from a single glucose molecule, two NADH molecules are generated in total by the end of glycolysis.

Understanding this stoichiometry is essential for grasping how much energy potential is created during glucose metabolism and its implications for cellular respiration as a whole. Thus, the accurate count of two NADH molecules highlights the energetic significance of the glycolytic pathway.