Fermentation Anaerobic respiration Anaerobic bacteria n Use inorganic

Fermentation Anaerobic respiration

Anaerobic bacteria n Use inorganic molecules as their electron acceptors n n Nitrates sulfate

Fermentation n Pyruvate is reduced by NADH n n Alcohol and carbon dioxide OR lactate

Alcoholic fermentation n Ex. Yeasts, produce ethyl alcohol and CO 2 Alcohol usually ends up killing the yeast.

Lactic Acid Fermentation n n Ex. Animals, some bacteria and fungi NADH reduces pyruvate to lactate Muscle cells see this when oxygen is not delivered to the cells fast enough. Bacteria produce cheese, yogurt, important chemicals (isopropanol, acetic acid)

Fermentation n Advantages: n n 2 ATP, use in certain animals in tissues Disadvantages: n n Toxic to cells, upon build up it can change the p. H and cause muscle fatigue. Oxygen debt – amount of O 2 needed to rid body of lactate, lactate goes to liver where it is converted back to pyruvate.

Fermentation n Efficiency n n 2 ATP = 14. 6 kcal Complete breakdown to CO 2 and water possible energy yield of 686 kcal = 2. 1% Aerobic respiration = 39% effieciency

Fermentation n Input: glucose and 2 ATP (glycolysis) 2 pyruvate n n 2 lactate 2 alcohol and carbon dioxide and 2 ATP

Metabolic pool n Degradative reactions catabolism exergonic n n Ex. Glucose, fat, proteins can be used as energy sources as well and enter the metabolic pathway Synthetic reactions Anabolism endergonic n Compounds that enter the pathways are oxidized to substrates that can be used for biosynthesis