The mitochondria are often referred to as the "powerhouses" of the cell because they generate adenosine triphosphate (ATP), the primary energy currency in biological systems. Through the process of cellular respiration, mitochondria convert glucose and oxygen into ATP, carbon dioxide, and water. This energy is essential for various cellular functions, including muscle contraction, cell division, and the synthesis of biomolecules. Mitochondria also play roles in metabolism and regulating cellular apoptosis, highlighting their importance beyond just energy production.