Respiration is a cellular process that includes different metabolic pathways and enzymes which play an integral role in its different stages. Respiration takes place in the cytosol and mitochondria of the cells, and releases energy in the form of ATP which is then utilized by the different bodily processes like muscle contractions, movement, growth and repair of cells. Respiration involves the oxidation of organic compounds like glucose (breakdown of glucose using oxygen), hence producing carbon dioxide and water. There are two types of respirations; aerobic and anaerobic that happens in yeasts, plants and humans. In aerobic respiration, there is a complete breakdown of glucose which occurs in the presence of oxygen. Hence, a large amount of energy is released. This energy comes from the C-H bonds in sugar molecules, as glucose is broken down completely, more of such bonds break and release energy in the form of ATP. The word and chemical equations are given below respectively: Glucose + Oxygen →Carbon dioxide + Water + a lot of Energy (ATP) C6H12O6 + 6O2 → 6CO2 + 6H2O In anaerobic respiration, the incomplete breakdown of glucose occurs in which oxygen is absent, and a very small amount of energy is released as compared to the aerobic respiration. Very few C-H bonds are broken due to which less energy is released. It produces various products that depend on the type of organism. In humans/ animals, when there is a high amount of exertion, the energy demand in the muscles increases. Also, as many muscles engage in contracting, the oxygen becomes limiting for some of them, hence they start doing anaerobic respiration. As partial breakdown of glucose happens, lactic acid is produced. The lactic acid can build up in muscles causing fatigue, hence to replace it, heavy breathing begins that replaces the oxygen debt (oxygen debt is the amount of oxygen needed to clear up lactic acid by reacting with it and forming water and carbon dioxide). The word and chemical equations are given below respectively. Glucose →Lactic Acid + Less amount of energy C6H12O6→2C3H6O3 To wrap up: 