Aerobic respiration requires oxygen. It is the preferred method of pyruvate breakdown. It consists of two metabolic pathways:

1. Citric acid cycle
2. Oxidative phosphorylation

In aerobic respiration, an electron is transferred from an energy-rich atom (such as a carbon atom in an organic molecule) to an oxygen atom, via an electron transport chain. Oxygen serves as the "terminal electron acceptor" in the electron transport chain. In the process, it yields 36 ATP molecules, as well as carbon dioxide, and water. This makes for a total gain of 38 ATP molecules during cellular respiration. This takes place in the mitochondria in eukaryotic cells, and at the cell membrane in prokaryotic cells.

See also Cellular respiration.