In oxidative metabolism, what fuels are primarily used to synthesize ATP?

In oxidative metabolism, the primary fuels used to synthesize ATP are carbohydrates and fats. This process occurs in the mitochondria of cells and is crucial for producing energy during prolonged, moderate-intensity activities.

Carbohydrates, in the form of glucose, can enter the energy production pathway through glycolysis and then be further oxidized in the citric acid cycle. Fats are utilized by breaking down fatty acids via a process called beta-oxidation, which also contributes to the citric acid cycle. Both carbohydrates and fats ultimately lead to the production of ATP through oxidative phosphorylation, where electrons are transferred through the electron transport chain, resulting in the synthesis of ATP from ADP and inorganic phosphate.

Proteins can also be used for energy, but they are not a primary fuel source in oxidative metabolism under normal conditions. Typically, proteins are reserved for other critical functions such as tissue repair and enzyme synthesis, and their breakdown for energy occurs more often in extreme situations, such as prolonged fasting or intense endurance activities. Vitamins and minerals do not serve as direct sources of energy but are essential for various metabolic processes and enzyme functions.