How many ATP are formed through the complete oxidation of glucose in the Krebs cycle and ETC?

The complete oxidation of one molecule of glucose during cellular respiration involves several stages, including glycolysis, the Krebs cycle (also known as the citric acid cycle), and the electron transport chain (ETC).

In total, from one glucose molecule, glycolysis yields 2 ATP in its substrate-level phosphorylation process and produces 2 molecules of pyruvate, which are then converted into acetyl-CoA that enters the Krebs cycle. Each turn of the Krebs cycle produces 1 ATP (or its equivalent) per acetyl-CoA; since each glucose molecule generates 2 acetyl-CoA, this results in 2 ATP from the Krebs cycle as well.

Furthermore, the reduced coenzymes NADH and FADH2 produced during both glycolysis and the Krebs cycle provide electrons to the electron transport chain. Each NADH can yield approximately 2.5 ATP, and each FADH2 yields approximately 1.5 ATP through oxidative phosphorylation. The complete oxidation of glucose leads to the formation of about 10 NADH and 2 FADH2 molecules overall.

When calculated:

• From glycolysis: 2 NADH × 2.5 ATP = 5 ATP.

• From the conversion of pyruvate to