Anaerobic

All cells carry out the process of glycolysis, which is an example of anaerobic respiration. Glycolysis is the initial phase of cellular respiration that involves the splitting of the six-carbon glucose molecule into two three-carbon pyruvate fragments. This is the main energy-releasing pathway that occurs in the cytoplasm of all prokaryotes and eukaryotes, and no oxygen is required. During glycolysis, oxidation (the removal of electrons and hydrogen ions) is facilitated by the coenzyme NAD⁺ (nicotinamide adenine dinucleotide), which is then reduced to NADH. Only two ATP molecules result from this initial anaerobic reaction. This is a small amount of energy when compared to the net aerobic energy yield of 36 ATP in the complete oxidation of one molecule of glucose.