1. Carbohydrates: Primarily glucose, which is broken down through glycolysis and the citric acid cycle to generate ATP and electron carriers.
2. Lipids (fats): Fats are broken down into glycerol and fatty acids. Glycerol can enter glycolysis, while fatty acids are broken down through beta-oxidation, producing acetyl-CoA which enters the citric acid cycle. This process yields a significant amount of ATP.
3. Proteins: While less common than carbohydrates and lipids, proteins can be broken down into amino acids. Amino acids can be converted into intermediates of glycolysis and the citric acid cycle, allowing them to contribute to ATP production.
While all three macromolecules can be used to produce ATP, carbohydrates are the most common and efficient source.
