When oxygen is present, aerobic cellular respiration takes place. This process can be divided into three main phases: glycolysis, the Krebs cycle (sometimes called the tricarboxylic acid, TCA cycle, or citric acid cycle), and the electron transport chain. As by-products, CO2 and H2O are produced, which leave the body via respiration, urination and perspiration. ATP are produced during all three of the phases, and the maximum yield for aerobic respiration is 38 ATP.
The general equation for the cellular respiration process is:
Glucose (C6H12O6) + 6 O2 + 38 ADP → 6 CO2 + 6 H2O + 38 ATP + heat
Figure: Overview of the aerobic cellular respiration process.