What is common between Aerobic and Anaerobic Respiration?

Glycolysis is common between Aerobic and Anaerobic Respiration.

Cellular respiration is the process by which glucose is broken down to form ATP molecules, which act as carriers of cellular energy. The first phase is called glycolysis and is common to both aerobic (respiration in the presence of oxygen) and anaerobic (respiration in the absence of oxygen) respiration.

During glycolysis, glucose is split to forms two pyruvate molecules and 2 molecules of ATP. This occurs in the cytoplasm of the cell.

If oxygen in present, the pyruvate molecules will be used in the Krebs cycle, to yield more ATP molecules. If oxygen is absent, the pyruvate is converted into lactic acid, or ethanol and carbon dioxide, in animals or plants, respectively.