What is the difference between aerobic and anaerobic respiration?

Respiration isn’t just breathing: it is the conversion of glucose into energy through a series of reactions in every cell. It provides energy for movement, warmth, and to build molecules up from smaller molecules, such as protein from amino acids. Aerobic respiration means to use oxygen to break down glucose into energy with this equation: Glucose + Oxygen → Carbon Dioxide + Water + Energy. Anaerobic respiration means no oxygen is used in the breakdown of glucose. Without oxygen, it is broken down incompletely into lactic acid and energy: Glucose → Lactic Acid + Energy. Anaerobic respiration in mammals will occur if oxygen isn't reaching tissues quickly enough, for example in exercise where the muscles are being used more than normal. We can feel the lactic acid build up as a stitch. Anaerobic respiration doesn’t release energy as efficiently as aerobic, so it is only used when aerobic can't. Once oxygen has returned to the cells (eg muscles), it will remove the lactic acid.