For one molecule of glucose, how many ATP does the oxidative system produce?

The oxidative system, which includes aerobic metabolism, is the primary pathway for producing ATP from glucose during prolonged, steady-state exercise. When one molecule of glucose undergoes glycolysis, it is converted to pyruvate, yielding a small amount of ATP. The pyruvate then enters the mitochondria where it is further oxidized in the Krebs cycle.

In total, the complete oxidation of one molecule of glucose through glycolysis, the Krebs cycle, and the electron transport chain generates a significant amount of ATP. Specifically, the process can yield around 36 to 38 ATP molecules, depending on the efficiency of the electron transport chain and the shuttle systems involved in transferring reducing equivalents from glycolysis into the mitochondria.

When we reference the most commonly cited figure of 38 ATP, we consider both the direct ATP yield and the reduction equivalents generated (NADH and FADH2) that are oxidized in the electron transport chain. This total accounts for all ATP produced through substrate-level phosphorylation during glycolysis and the Krebs cycle, as well as the oxidative phosphorylation that occurs in the electron transport chain.

Therefore, stating that the oxidative system produces 38 ATP from one molecule of glucose reflects a comprehensive picture of aerobic metabolism, making this answer the