How many ATP molecules can be generated from one molecule of NADH?

One molecule of NADH can generate approximately 2.5 ATP molecules through the process of oxidative phosphorylation in cellular respiration. This calculation is based on the electron transport chain's efficiency in converting the energy stored in NADH into ATP.

NADH, produced during various metabolic processes including glycolysis, the citric acid cycle, and the conversion of pyruvate to acetyl-CoA, donates its electrons to the electron transport chain, specifically to Complex I (NADH dehydrogenase). As electrons are passed along the chain through various complexes, protons are pumped from the mitochondrial matrix into the intermembrane space, creating a proton gradient.

When protons flow back into the matrix through ATP synthase, ATP is synthesized from ADP and inorganic phosphate. The approximately 2.5 ATP produced per NADH takes into account the number of protons pumped across the membrane and the ATP synthase's efficiency in utilizing the proton motive force during ATP synthesis.

This value can vary slightly depending on the organism and specific conditions, but the general consensus in biochemistry supports the generation of around 2.5 ATP from one NADH molecule.