Final answer:
The pathway that uses fat reserves to produce ATP is aerobic respiration, a process that includes beta-oxidation of fatty acids, the citric acid cycle, and oxidative phosphorylation, and supplies ATP for extended periods.
Step-by-step explanation:
The pathway that uses fat reserves to produce ATP is aerobic respiration.
Aerobic respiration is the process of breaking down glucose in the presence of oxygen to produce ATP, carbon dioxide, and water. This pathway occurs after the immediate stores of ATP and ATP generated from creatine phosphate are depleted. Fats, stored as triglycerides in fat tissue, can be broken down by the body into glycerol and fatty acids. The fatty acids enter the mitochondria, undergo beta-oxidation, and are converted to acetyl-CoA, which then enters the citric acid cycle. The energy released in the citric acid cycle is used to produce ATP through oxidative phosphorylation, a process that involves electron transport and chemiosmosis. This method is efficient and can supply ample ATP for hours, making it the primary source of ATP in resting or moderately active muscles.
The pathway that uses fat reserves to produce ATP is aerobic respiration. Aerobic respiration is the breakdown of glucose in the presence of oxygen to produce carbon dioxide, water, and ATP. It takes place in mitochondria and provides approximately 95% of the ATP required for resting or moderately active muscles.