Cellular respiration is performed by living cells in every variety of organism. It involves the production of an energy source within cells to be used as fuel for biological processes.
A cell's energy supply is highly dependent on cellular respiration. It may be performed as aerobic or anaerobic respiration. Aerobic respiration requires the intake and combination of oxygen with water molecules to convert glucose into energy to be used by cells. Anaerobic respiration allows for the conversion of glucose into energy without the presence of oxygen. It is utilized by bacteria or when an organism has a low supply of oxygen.
Both types of respiration begin with a process known as glycolysis, which begins the breaking down and conversion of carbohydrates into usable energy. Glycolysis is performed in the cytosol of eukaryotic cells, while organelles known as mitochondria perform the remaining processes of cellular respiration. Anaerobic respiration results in the production of pyruvic acid, which is a product of glucolysis used to cause fermentation of molecules essential to energy production.
Once glycolysis is performed, the process begins the stage of converting pyruvic acid into carbon dioxide and water. This results in the production of energy molecules known as ATP, which is the final product of cellular respiration.