Glycolysis is the first step in cellular respiration and occurs in the cytoplasm of the cell. The word glycolysis literally means “breaking down sugars”. During this process, the 6-carbon glucose molecule is split into two 3-carbon pyruvate molecules, producing only a small amount of energy (see detailed steps). Nearly all living organisms carry out glycolysis as part of their metabolism. The process does not use oxygen and is therefore anaerobic.