PACKET #29 CHAPTER #9 Anaerobic Respiration Cellular Respiration Without Oxygen

Anaerobic Respiration I For most animal and plant cells, glycolysis is only a prelude to the final stages of the breakdown of food molecules. Normally, pyruvate is transported to the mitochondria and is converted into CO 2 plus ACoA.  Ultimately to more CO 2, during the Kreb’s Cycle, and H 2 O, using oxygen, during oxidative phosphorylation

Anaerobic Respiration II For organisms that do not utilize molecular oxygen, and are able to grow and divide without it, glycolysis is the principle source of a cell’s ATP. If no oxygen is available, the pyruvates formed at the end of glycolysis do not enter the Kreb’s Cycle but follow one of a number of anaerobic pathways that are often referred to as fermentation.

Anaerobic Respiration III The pathways frequently use up 2 H + and NAD + via oxidation—allowing the NAD + to be used again in glycolysis.

Lactate Acid Fermentation Alcoholic Fermentation Glucose + 2P + 2ADP  2 lactate + 2 ATP + 2 H 2 O  A small amount of energy is released  Occurs in muscles during intense exercise.  Increase in lactate results in cramps. Two Steps  Glycolysis  NAD + Regeneration  This stage produces NAD + and lactate. Glucose + 2P + 2ADP  2 ethanol + 2ATP + 2CO 2  A small amount of energy is released  Occurs in anaerobic bacteria and yeasts  Useful in the production of alcoholic beverages and bread. Three Steps  Glycolysis  Pyruvate to acetaldehyde  NAD + Regeneration Fermentation