Cellular respiration is a biological process in which cells convert sugar, amino acids and fatty acids into energy utilized by the cell. The process plays an essential role in maintaining the biological functions of all living cells.
Cellular respiration begins by breaking down sugars known as glucose during a process called glycolysis. Both types of cellular respiration require pyruvate to function, which is the initial product of glycolysis. Glycolysis can begin with or without the intake of oxygen by the cell. Aerobic respiration, which has oxygen present, mostly takes place in organelles known as mitochondria, which are found in complex eukaryotic cells. Anaerobic respiration, which lacks oxygen, occurs in the fluid layer of a cell known as the cytoplasm and produces more energy than anaerobic respiration.
Glycolysis allows energy sources to be converted into molecules known as ATP, the final energy product of cellular respiration. A process known as the TCA cycle utilizes pyruvate to produce ATP, which is then chemically bonded to electron chains that allow it to be stored, transported and utilized wherever needed. Cellular respiration releases carbon dioxide as a waste product, which binds with water molecules, forming carbonic acid, which helps maintain the pH levels of blood.