Respiration

Respiration - Fermentation to lactate and ethanol...

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Biology 1201 Section 1 Spring 2007 Exergonic reactions _release__free__ energy. Endergonic reactions absorbs free_ energy ATP (A denosine T riP hosphate) - energy currency of the cell ATP is hydrolyzed to ADP and inorganic phosphate, releasing approximately 7.3 kcal/mol of energy (= -7.3 or +7.3?) NADH, NADPH and FADH 2 - reducing power Creatine Phosphate - high energy phosphate store in __vertebrates__________ Arginine Phosphate - high energy phosphate store in __invertebrates___________ Catabolic processes – produce ATP and reducing power Anabolic processes –require ATP and reducing power Metabolism converts molecules in small steps, each catalyzed by a specific enzyme. In the cytoplasm glucose is oxidized to pyruvate. Depending on the availability of oxygen, there are two pathways for the further metabolism of pyruvate: In the _absence__ of adequate oxygen , glucose is fermented in the cytoplasm to lactic acid (animals) or ethanol (plants and yeast [and sometimes in animals, e.g., cold-adapted goldfish]).
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Unformatted text preview: Fermentation to lactate and ethanol regenerates NAD so that glycolysis can continue. Anaerobic glycolysis results in the net production of 2 ATP. (3 ATP are produced when glycogen is the starting material.) In the __presence__ of adequate oxygen pyruvate is channeled into the Krebs cycle (in mitochondria) , by being converted to acetyl CoA. Because pyruvate is a 3-carbon compound and glucose is a 6-carbon compound, there are two "turns" of the Krebs cycle per glucose molecule. CO 2 , ATP and reducing power , NADH and FADH 2 are produced. The NADH and FADH 2 , in the mitochondrion , through the electron transport chain and oxidative phosphorylation are used to produce ATP. It is at this step that oxygen is used (to produce H 2 0). 3 ATP are produced per NADH. 2 ATP are produced per FADH 2 . Under aerobic conditions a net _36__ to __38___ molecules of ATP are produced per glucose molecule ....
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