There are two types of respiration. One is aerobic respiration and the other is anaerobic respiration. This type of respiration occurs in the presence of oxygen Here oxygen is utilised to break down the food (glucose) to release high amount of energy this is called aerobic respiration. This type of respiration occurs in the absence of oxygen. During respiration in yeast and bacteria, oxygen is not involved in the oxidation of food. Food (glucose) is broken down into ethyl alcohol and carbon dioxide this is called anaerobic respiration. 