Which type of respiration produces the most ATP per glucose molecule?

Aerobic respiration is the process that produces the most ATP per glucose molecule because it fully oxidizes glucose in the presence of oxygen. During aerobic respiration, glucose undergoes a series of reactions in the cytoplasm and enters the mitochondria, where it is broken down completely through the Krebs cycle and the electron transport chain.

In these processes, a total of approximately 36 to 38 ATP molecules can be generated from one molecule of glucose, depending on the efficiency of the transport of electrons into the mitochondria. The use of oxygen enables the complete oxidation of glucose and the maximization of energy production.

In contrast, anaerobic respiration and fermentation result in significantly fewer ATP molecules. Anaerobic respiration yields only a small amount of ATP because it partially breaks down glucose without using oxygen, while fermentation, which can take place in certain organisms and under specific conditions, also leads to a limited return of ATP, typically 2 ATP per glucose. Glycolysis, while producing some ATP, is only the initial stage of both aerobic and anaerobic pathways and thus does not produce as much ATP on its own as aerobic respiration does.