The process of obtaining usable energy from food in cells is called cellular respiration. During cellular respiration, glucose and oxygen are converted into ATP (adenosine triphosphate), the energy currency of the cell, along with carbon dioxide and water as byproducts. This process occurs in the mitochondria and is vital for sustaining cellular functions and overall metabolism in organisms. Cellular respiration can occur aerobically (with oxygen) or anaerobically (without oxygen), influencing energy production efficiency and impact on the organism's survival.