Cellular respiration, with a series of steps and intracellular functions, is the method used by cells to release energy from chemical bonds of molecules, such as food molecules, that provide energy and sustenance for the essential processes of life. Cellular respiration is conducted within the bodies of all living cells. This process takes place in the form of aerobic or anaerobic respiration.
The cellular respiration process that relies on oxygen is called aerobic respiration, while no oxygen is required for anaerobic respiration. Cellular respiration takes place in several kinds of cells, including prokaryotic cells, which carry out cellular respiration in the cytoplasm or inner surfaces of cells. However, cellular respiration takes place more frequently in eukaryotic cells where mitochondria are present and used for many reactions. Regardless of whether cellular respiration uses aerobic or anaerobic methods, the process is the same and begins with the production of glucose, which is a type of sugar introduced into the body during food consumption. Glucose is then broken down into glycolysis, which is a type of sugar that can be used by all cells. Then, glycolysis goes through the TCA cycle, which breaks it down into even smaller particles. This substance is then used to create electron transport reactions and finally ends up as ATP, or the energy currency of cells.