The respiration which takes place without oxygen is known as anaerobic respiration. The microorganisms like yeast break down glucose (food) into ethanol, carbon dioxide and releases energy. Therefore, the whole process of anaerobic respiration takes place in the cytoplasm of cells. Lactic acid is the end-product of anaerobic respiration in animals. In animals When glucose molecules break down in anaerobic respiration, the pyruvate stays in cells. The lactic acid needs to be oxidized to water and carbon dioxide later.
There are two main types of anaerobic respiration, alcoholic fermentation and lactic acid fermentation.
- Alcoholic fermentation is the process of converting glucose into the molecule ethanol.
- Lactic acid fermentation occurs in animals after glycolysis if there is not enough oxygen to perform aerobic respiration.