How many NADH molecules are produced in glycolysis?

During glycolysis, a total of two NADH molecules are produced. This process takes place in the cytoplasm and involves the breakdown of one molecule of glucose into two molecules of pyruvate. In the energy investment phase, glucose is phosphorylated and processed through several steps, and during the energy payoff phase, electrons are transferred to NAD+ to form NADH.

Specifically, one of the key steps involves the enzyme glyceraldehyde-3-phosphate dehydrogenase, which catalyzes the oxidation and phosphorylation of glyceraldehyde-3-phosphate. In this reaction, NAD+ accepts electrons and is reduced to NADH. Since glycolysis involves two molecules of glyceraldehyde-3-phosphate (derived from one glucose molecule), two NADH molecules are generated overall. This is critical because NADH carries high-energy electrons to the electron transport chain, where they contribute to the production of ATP during oxidative phosphorylation.