Catabolism is the set of metabolic pathways that breakdown molecules such as carbohydrates, fats, and proteins into smaller units to release energy for cellular processes. This process involves the breaking down of complex molecules into simpler ones through chemical reactions, usually resulting in the release of energy in the form of ATP. Catabolism is essential for providing cells with the energy they need to carry out various biological functions and is closely related to anabolism, the process by which cells build complex molecules from simpler ones. Studies in catabolism play a crucial role in understanding how cells extract energy from nutrients and maintain their basic functions.