The basic unit of measure for energy in metabolic processes is the calorie (or more commonly in biological contexts, the kilocalorie). This unit quantifies the amount of energy that food provides when consumed, which is critical for sustaining bodily functions, growth, and maintenance. In cellular metabolism, energy is also often measured in ATP (adenosine triphosphate), the primary energy carrier in cells. Understanding these energy units is essential for studying how organisms convert food into energy, enabling them to perform vital biological processes.