• Assume that an average person consumes 2000 Calories (kcal) per day of glucose.
• Glucose (molecular weight 180) contains about 700 kcal/mol of energy (or 2900 kJ/mol).
• Assume the catabolic oxidation of one mole of glucose produces about 30 moles of ATP (molecular weight about 500).

How much ATP can that person produce from the glucose consumed?

2000 Calories / 700 Calories/mol = 2.9 moles glucose

2.9 moles glucose X 30 moles ATP/mol glucose = 87 moles ATP

500 g/mol ATP X 87 moles ATP = 43,500 g (43.5 kg) of ATP produced

This is the reason for metabolic cycles, in which ATP is hydrolyzed to ADP, which is phosphorylated to form ATP, which is hydrolyzed to ADP, which is phosphorylated to form ATP . . . The amount of ATP and ADP in the cell remain relatively constant because of the continual oxidative phosphorylation that keeps phosphorylating ADP from the energy released by the oxidation of glucose.