E transport and oxidative phosphorylation on the

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Unformatted text preview: rylation on the inner membrane of mitochondria to produce ATP c) After running for a while, the man felt exhausted and he had problems catching his breath. How was glucose metabolized under this condition when oxygen supply was severely limited? NO need for names of enzymes and chemical structures. Glucose is metabolized to pyruvate via glycolysis generating ATP and NADH. When oxygen supply is limited, mitochondrial citric acid cycle and oxidative phosphorylation cannot occur. Pyruvate has to be reduced to lactate (lactic acid) so that NADH can be reoxidized to NAD+ in support of continuous glucose metabolism via glycolysis (NAD+ is needed in 5 glycolysis). Therefore, when oxygen supply is limited, glycolysis is the only process to produce small amounts of ATP and lactate is accumulated as an end product. d) The man finally reached safety when he felt fatigue in his muscles. Now he could rest and recover from the strenuous running. What happened to his muscle and liver cells at this stage? Your answer should include 1) names of pathways involved and 2) cellular locations for each pathway. However, NO need for names of enzymes and chemical structures. 1) Lactate accumulated in the muscle is secreted to blood and eventually picked up by liver cells. 2) Liver cells convert lactate to glucose via gluconeogenesis (in cytosol). 3) The regenerated glucose can be sent to muscle for future use. 4) The whole cycle between muscle (glucose lactate) and liver (lactate glucose) is called Cori cycle. e) Now that the shocking experience to this man is over and the epinephrine level starts to decline, how does his body turn off the signaling transduction pathway that has been activated by epinephrine? 1. Activated 7TM receptor can be turned off by interacting with “arrestin”. 2. Heterotrimeric G-protein cycles from “on” state (α -subunit with GTP) to “off” state (GTP is hydrolyzed to give GDP). 3. cAMP can be hydrolyzed (destroyed) by phosphodiesterase. 4. Protein kinase...
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This note was uploaded on 01/26/2014 for the course BIO 2960 taught by Professor Hafer during the Spring '12 term at University of Illinois, Urbana Champaign.

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