Which energy system has a very slow rate of ATP synthesis?

Which energy system has a very slow rate of ATP synthesis?

• A. Lactic acid system
• B. Aerobic glycolysis
• C. Aerobic lipolysis
• D. ATP-PC system

Answer: (C)

The rate at which ATP is produced varies between energy systems, and fat oxidation (aerobic lipolysis) is the slowest. When activity is long and intensity is low, fats are mobilized and oxidized in the mitochondria through beta-oxidation, the Krebs cycle, and oxidative phosphorylation. This chain of steps takes time and is limited by oxygen delivery, so ATP is formed at a very slow rate. Yet fats provide a large amount of ATP per molecule, which supports extended endurance activities. By contrast, the immediate phosphagen system is fastest but only lasts seconds, and glycolytic pathways supply ATP more quickly but for a shorter duration, with aerobic carbohydrate metabolism being slower than glycolysis but faster than fat oxidation.

The rate at which ATP is produced varies between energy systems, and fat oxidation (aerobic lipolysis) is the slowest. When activity is long and intensity is low, fats are mobilized and oxidized in the mitochondria through beta-oxidation, the Krebs cycle, and oxidative phosphorylation. This chain of steps takes time and is limited by oxygen delivery, so ATP is formed at a very slow rate. Yet fats provide a large amount of ATP per molecule, which supports extended endurance activities. By contrast, the immediate phosphagen system is fastest but only lasts seconds, and glycolytic pathways supply ATP more quickly but for a shorter duration, with aerobic carbohydrate metabolism being slower than glycolysis but faster than fat oxidation.