1. Cellular Respiration In cellular respiration living things release the energy stored in food molecules. Cells may use aerobic respiration (using oxygen) or anaerobic pathways (without oxygen) Both aerobic and anaerobic respiration begin with the process of glycolysis.

2. Aerobic Respiration In aerobic respiration oxygen is used. Aerobic respiration also needs glucose for fuel and enzymes to help the reactions occur. This releases the greatest amount of energy and is required to run most living things. The products aerobic respiration are energy, in the form of ATP, carbon dioxide and water.

3. Anaerobic Fermentation Two forms Alcohol » Happens in yeast and the final product is ethyl alcohol and carbon dioxide Lactic Acid » Happens in your muscle cells when energy is needed faster than can be provided by aerobic respiration.