Which substrate yields the highest ATP per mole in the data?

Which substrate yields the highest ATP per mole in the data?

• A. Fat
• B. Glycogen (aerobic)
• C. Glycogen (anaerobic)
• D. Creatine phosphate

Answer: (A)

Energy yield per mole of substrate is driven by how much energy can be released from its oxidation. Fats contain long chains of carbon and hydrogen that, when oxidized, produce many acetyl-CoA units fed into the citric acid cycle and then the electron transport chain. This cascade releases a large amount of ATP overall. In practical terms, a typical fatty acid molecule can yield well over 100 ATP, far more than carbohydrates or creatine phosphate. Carbohydrates, even glycogen, unlock far fewer ATP per mole because their oxidation goes through glycolysis and the TCA cycle with a finite amount of energy produced; glycogen offers a slight advantage over glucose by saving some initial ATP, but the total remains in the low tens of ATP per glucose unit. Creatine phosphate, on the other hand, provides only about one ATP per molecule, delivering rapid but very limited energy. So, the data show that fat yields the highest ATP per mole, making it the best source for maximizing ATP production.

Energy yield per mole of substrate is driven by how much energy can be released from its oxidation. Fats contain long chains of carbon and hydrogen that, when oxidized, produce many acetyl-CoA units fed into the citric acid cycle and then the electron transport chain. This cascade releases a large amount of ATP overall. In practical terms, a typical fatty acid molecule can yield well over 100 ATP, far more than carbohydrates or creatine phosphate.

Carbohydrates, even glycogen, unlock far fewer ATP per mole because their oxidation goes through glycolysis and the TCA cycle with a finite amount of energy produced; glycogen offers a slight advantage over glucose by saving some initial ATP, but the total remains in the low tens of ATP per glucose unit. Creatine phosphate, on the other hand, provides only about one ATP per molecule, delivering rapid but very limited energy.

So, the data show that fat yields the highest ATP per mole, making it the best source for maximizing ATP production.