Which type of respiration produces more energy, aerobic or anaerobic?

Aerobic respiration produces more energy than anaerobic respiration due to its reliance on oxygen and its more efficient metabolic pathways. In aerobic respiration, glucose is fully oxidized to carbon dioxide and water, allowing for the complete breakdown of pyruvate through the Krebs cycle and the electron transport chain. This process generates a large yield of adenosine triphosphate (ATP), the energy currency of the cell.

In contrast, anaerobic respiration occurs in the absence of oxygen and involves partial oxidation of glucose. This process yields significantly less ATP because it relies on fermentation pathways, like lactic acid or alcoholic fermentation, which do not utilize the Krebs cycle or the full electron transport chain. Consequently, the ATP yield in anaerobic respiration is much lower—generally only 2 ATP molecules per glucose molecule compared to up to 38 ATP molecules produced during aerobic respiration.

Thus, aerobic respiration is the more energy-efficient process, allowing organisms that can utilize oxygen to derive greater energy from glucose compared to those that rely solely on anaerobic pathways.