aerobic respiration

The cellular process in which inhaled oxygen is used to extract energy from food molecules and store it as ATP, the universal energy currency. Glucose and fatty acids are oxidized stepwise through glycolysis, the citric acid cycle, and the electron transport chain, with oxygen serving as the final electron acceptor and water as the end product alongside carbon dioxide. It is the reason breathing and eating are inseparable: without oxygen, cells fall back on inefficient fermentation that cannot sustain complex life. Exercise physiologists measure its rate through oxygen consumption to gauge fitness and calorie burn, while food scientists invoke it to explain why fresh produce continues to respire after harvest, consuming sugars and generating heat that must be managed in cold storage to preserve quality.