Cellular respiration involves a series of chemical reactions that convert glucose into energy in the form of ATP. Glucose undergoes glycolysis to form pyruvic acid, which then enters the Krebs cycle in the mitochondria. Electrons are passed through the electron transport chain, releasing energy to produce ATP. Oxygen is the final electron acceptor in this process, with carbon dioxide and water as byproducts. This allows living cells to harness the energy stored in glucose and other nutrients to power their functions.