Final answer:
Catabolism is the biological process where large complex molecules are broken down into smaller molecules, releasing energy. This energy primarily manifests as ATP, which is used for cellular functions and as heat. Catabolism is part of metabolism, which includes both energy-releasing and energy-consuming processes.
Step-by-step explanation:
Catabolism refers to the biological processes in which large complex molecules are broken down into smaller simpler molecules. This process is crucial as it releases energy that is necessary for various metabolic activities within the body. For example, the food we consume is composed of complex molecules such as carbohydrates, proteins, and lipids, which are catabolized into their constituent smaller parts like sugars, amino acids, and fatty acids, respectively.
ATP, or adenosine triphosphate, plays a central role in metabolism. Approximately 40% of the energy yielded from catabolic reactions is directly transferred to ATP, which can then be used for cellular functions such as building and repairing tissues. The rest of the energy is released as heat, which helps maintain body temperature.
These catabolic reactions are a part of a larger set of chemical reactions known as metabolism, which includes both catabolic and anabolic pathways. Anabolic pathways are responsible for synthesizing larger molecules from smaller units and require energy, whereas catabolic pathways break down complex molecules to release energy.