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14 Cards in this Set
- Front
- Back
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About how many grams of glucose are used by humans every day?
How much of this goes to the brain? Body fluids? |
-160g
-75% or 120g! -20g to body fluids |
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How many grams of glucose can glycogen store?
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-160-180g
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What is Gluconeogenesis?
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-the synthesis of glucose from non-carbohydrate sources when it isn't available
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What are the major sites of gluconeogenesis and what percent do they contribute?
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-liver 90%
-kidney 10% |
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What are the major substrates for gluconeogenesis?
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-lactate
-amino acids -pyruvate -TCA cylce intermediates |
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Glycolysis is irreversible, but gluconeogenesis can reverse them. What are the 4 new reactions?
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-conversion of pyruvate to phosphoenolpyrucate (2 steps)
-going from gructose-1,6-bisphosphate to fructose-6-phosphate -removing the phosphate from glucose-6-phosphate |
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For animals lacking mitochondrial PEP carboxykinase, how is OAA transported (what does this stand for)?
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-Oxaloacetate is transported by the malate shuttle after converting mitochondrial OAA to malate
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How does gluconeogensis reverse the phosphofructokinase reaction of glycolysis?
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-it isn't reversible so gluconeogenesis bypasses it with fructose-1,6-bisphosphatase
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In step three of gluconeogenesis, where it the enzyme Glucose-6-phosphatase found?
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-only in the liver, kidney, pancreas, and small intestine
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What are the individual energy requirements for gluconeogenesis?
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-2 ATP for pyruvate carboxylase
-2 GTP for PEP Carboxykinase -2 ATP for Phosphoglycerate kinase -2 NADH for glyceraldehyde-3-P DH |
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What are the overall energy requirements for gluconeogenesis?
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-6 ATP and 2 NADH to synthesize one molecule of glucose
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Why is it important to control glycolysis/gluconeogenesis?
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-ATP would be hydrolysed for no purpose and wasted
*one cyle is oxidation of glucose, the other is for glucose synthesis |
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What controls liver PFK-1?
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-Fructose-2,6-bisphosphate
*graphs a nice tapering arc |
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What affect does Fructose-2,6-Bisphosphate have on glycolysis and gluconeogensis?
How does this work? |
-activates glycolysis
-inhibits gluconeogenesis *F-2,6-P increase the inhibition of F-1,6-P by AMP |
