BIOCHEMISTRY A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site lactic acid An organic acid, (2-hydroxypropanoic acid, CH3CH(OH)COOH), formed as a product of glycolysis – the break down of glucose by anaerobic metabolism (chemical processes that don't require oxygen). Glycolysis is an essential step in the utilization of the energy in food by many animal cells, and particularly during contraction of skeletal muscle (also known as striped or striated muscle) in vertebrates. Lactic acid is also formed as a result of the metabolism of many bacteria, for example, from lactose in the souring of milk (hence its name). Aerobic metabolism occurs only when there is too little oxygen for the more usual aerobic metabolism. For example, lactic acid is produced by muscles during vigorous exercise and is one of the factors that contributes to contract. Lactic acid is also produced in tissues when they receive insufficient oxygen due to impairment of their blood supply in heart attack (myocardial infarction) or shock. Normally, lactic acid is removed from the blood by the liver. If lactic acid accumulates, a condition called lactic acidosis results. Lactic acid is a colorless, crystalline solid (melting point 18°C) that occurs in three stereoisomeric forms. dl-lactic acid, a mixture of equal amounts of (dextrorotatory) d-acid and (laevorotatory) l-acid, is formed by the action of certain bacteria on lactose, as mentioned above. The d-form, sarcolactic acid, occurs in muscle tissue. The optically inactive dl-form is used in dyeing and tanning. Related category    • BIOCHEMISTRY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP