The primary process by which glucose is metabolized is through cellular respiration. This multi-step biochemical pathway occurs in the cytoplasm and mitochondria of cells, allowing glucose to be broken down to produce adenosine triphosphate (ATP), the energy currency of the cell. The process can be aerobic, requiring oxygen, or anaerobic, occurring in the absence of oxygen. The overall reaction releases energy stored in glucose, generating byproducts such as carbon dioxide and water. Cellular respiration is essential for energy production in both plants and animals.