Human muscle cells are facultative anaerobes that perform lactic acid fermentation when oxygen is depleted from muscle tissues. During periods of high physical activity, such as a 100-meter sprint, ATP is rapidly used for muscle contraction. The limited oxygen delivered to muscle cells becomes a problem, and aerobic respiration is blocked. In Anaerobic respiration, the ATP provided by rapid fermentation, temporarily provides energy to maintain muscle function in the absence of oxygen until oxygen levels are restored. (SC.912. L.18.9 – Sub Cat. SC.912. L.18.8) Yeast also performs cellular respiration in the absence of oxygen, a process called Alcoholic Fermentation. What are two products of Alcoholic Fermentation?