Brief explanation about respiration

Respiration is the oxidation of respiratory substrates (mainly glucose) in the cells resulting in the release of carbon dioxide and energy. It involves release of energy in the form of ATP. The initial steps of glucose break down occurs in the cytoplasm and results in production of pyruvic acid. This process is called glycolysis or E. M. P. Pathway. One molecule of glucose breaks down to produce two molecules of pyruvic acid. Each pyruvic acid molecule has three carbon atoms. This pathway doesn't require oxygen. Aerobic respiration occurs in the presence of O2 where O2 is utilised. Glucose is completely broken down to release end products in the form of CO2 and water. It takes place in cytoplasm and mitochondria. Anaerobic respiration occurs in the cytoplasm in the absence of O2. Glucose is incompletely oxidised to release the end products in the form of ethyl alcohol and water (in plant cells and yeast) and lactic acid (in animal cells).