How many ATP are produced in total during cellular respiration?

During cellular respiration, a total of approximately 36 ATP molecules are produced when one molecule of glucose is fully oxidized. This total comes from three main stages: glycolysis, the citric acid cycle (Krebs cycle), and oxidative phosphorylation.

In glycolysis, which occurs in the cytoplasm, two ATP molecules are produced directly and two NADH molecules are generated. Each NADH can yield about 2.5 ATP when converted in the electron transport chain, contributing an additional 5 ATP to the overall count.

In the citric acid cycle, which takes place in the mitochondria, each glucose molecule (which produces two rounds of the cycle) yields two ATP (or GTP, depending on the cell type), six NADH (each yielding about 2.5 ATP), and two FADH2 (each yielding about 1.5 ATP). This contributes significantly to the total ATP count from glucose.

Finally, during oxidative phosphorylation, the electron transport chain and chemiosmosis produce the bulk of ATP. The combined contribution of glycolysis, the citric acid cycle, and oxidative phosphorylation results in an estimated total of about 36 ATP molecules produced per glucose molecule, depending on the efficiency of the system and the exact type