To determine which ATP production process stores the most energy, the key comparison is between aerobic respiration and anaerobic pathways (and photosynthesis in plants). Among these, aerobic respiration yields the highest net ATP per glucose molecule and thus stores the most energy in ATP molecules. Direct answer:
- Aerobic respiration (glycolysis followed by pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation) stores the most energy as ATP, typically around 29–30 ATP per glucose in contemporary estimates, well above anaerobic pathways.
Key points to explain:
- ATP stores energy in the bonds of its phosphate groups, and its hydrolysis releases usable free energy for cellular work. In aerobic respiration, the bulk of ATP is produced during oxidative phosphorylation via the electron transport chain and chemiosmotic coupling, where NADH and FADH2 donate electrons to generate a proton-m motive force that drives ATP synthase. This multistep process yields far more ATP than anaerobic glycolysis alone, which nets only 2 ATP per glucose. Photosynthetic ATP production in plants uses light energy to drive ATP synthesis, but in the context of “stored energy” for a single glucose substrate, aerobic respiration remains the most ATP-dense process in animal cells and most non-photosynthetic tissues.
