Metabolism encompasses all the complex chemical reactions that occur within an organism necessary to sustain life. These processes are broadly categorized into catabolism and anabolism. Catabolic pathways involve the breakdown of complex molecules, such as carbohydrates, lipids, and proteins, into simpler subunits, which releases stored chemical energy. Conversely, anabolic pathways use this released energy to synthesize larger, more complex molecules required for growth, repair, and energy storage. The ultimate goal of metabolic activity is the conversion of chemical energy derived from foodstuffs into usable forms, such as adenosine triphosphate (ATP), which fuels the vast array of cellular functions necessary for maintaining homeostasis.