Cellular respiration is what happens under aerobic conditions. Which simply means when oxygen is present. In the process of cellular respiration oxygen and sugars go through glycolysis which occurs in the cytosol to produce pyruvate. The pyruvate then goes into the mitochondria where it goes through the citric acid cycle and electron transport chain coupled with oxidative phosphorylation to produce energy in the form of ATP. Carbon dioxide is produced and voided as a byproduct from this process. The overall process of respiration sugars + oxygen becomes carbon dioxide + water and energy. Fermentation on the other hand is what happend and anaerobic conditions(when oxygen is not present). It only goes through glycolysis and the final producs from fermenation are ethanol/lactate.
