Tissue metabolism refers to the biochemical processes that occur within cells to maintain life. It involves the conversion of nutrients into energy, which is essential for cellular functions. This process includes pathways such as glycolysis, Krebs cycle, and oxidative phosphorylation, which help produce adenosine triphosphate (ATP), the energy currency of the cell. Different types of tissues, such as muscle, fat, and nervous tissue, have varying metabolic rates and requirements. For instance, muscle tissue requires more energy during physical activity, while fat tissue stores energy for later use. Understanding tissue metabolism is crucial for fields like nutrition and medicine.