The chemical process that occurs in the mitochondria during aerobic respiration is called oxidative phosphorylation. This process involves the conversion of biochemical energy from nutrients into adenosine triphosphate (ATP), the cell's primary energy carrier, in the presence of oxygen. Glucose is oxidized, and oxygen is reduced, resulting in the production of carbon dioxide and water as byproducts. Mitochondria are often referred to as the "powerhouses" of the cell because they play a crucial role in energy metabolism and maintaining cellular energy homeostasis.