glycolysis
Glycolysis is the first stage of cellular respiration. It takes place in the cytoplasm of the cell. The world glycolysis means "glucose splitting". That's exactly what happens in this stage. Enzymes split a molecule of glucose into two smaller molecules called pyruvate. This results in a net gain of two molecules of ATP. Other energy-storing molecules are also produced. Their energy will be used in stage 3 to make more ATP. Glycolysis does not require oxygen. Anything that doesn't need oxygen is described as anaerobic .