How many ATP molecules can be produced from one molecule of glucose during cellular respiration?

The maximum number of ATP molecules that can be produced from one glucose molecule during cellular respiration can vary based on the efficiency of the processes involved. Generally, aerobic cellular respiration consists of glycolysis, the citric acid cycle (Krebs cycle), and oxidative phosphorylation (electron transport chain and chemiosmosis).

When one molecule of glucose is metabolized, it can yield about 36 to 38 ATP molecules under optimal conditions, depending on factors such as the efficiency of the electron transport chain and the transport of NADH into mitochondria.

In the complete breakdown of glucose, glycolysis yields a net gain of 2 ATP and 2 NADH (which can generate about 3 to 5 ATP depending on the shuttle mechanism used to transport NADH into mitochondria). The citric acid cycle produces 2 ATP directly, along with several NADH and FADH2, which are further processed in oxidative phosphorylation. Here, the NADH produced can generate around 2.5 ATP, and FADH2 generates about 1.5 ATP during electron transport.

When calculating the total, combining these yields can lead to approximately 36 ATP in cells that utilize the direct transport of NADH into the mitochondria. However, in theory