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19 Cards in this Set
- Front
- Back
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What tissues use glc as the sole or major fuel?
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Nervous system, kidney medulla, testis, erythrocytes, embryonic tissues
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What are the sources of glc?
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Diet. Glycogen in liver. Gluconeogenesis in liver (minor in kidney).
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Where do the carbons come from for making glc?
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They are Not from CO2 or FA.
Lactate or pyruvate glycerol (platform of the FA breakdown) Glucogenic amino acids (18 of them) from protein breakdown (ketogenic only ones: Lys and Leu) 7 of the glycolysis steps are reversible and are used in gluconeogenesis (3 that are too negative deltaG have to go a different way) |
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What are the 3 glycolysis steps that can't be reversed?
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PEP -pyruvate kinase-> pyruvate
F-1,6-P ---F1,6 bisphosphatase--> F6P + Pi G6P --G6Pase--> Glc + Pi (LIVER only) |
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How do you get pyruvate to PEP?
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Pyruvate carboxylase in mitochondria. Uses ATP to add a CO2 --> oxaloacetate
OAA +NADH -> Malate + NAD -> go to cytoplasm -> OAA + NADH PEP carboxykinase + GTP --rearranges-> pyruvate + GDP + CO2 |
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What is an obligate activator?
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Allosteric activators help reactions take place, but the reaction can happen with the allosteric regulator.
An obligate activator is required in order for a reaction to take place. |
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What is the net energy loss for Pyr -> PEP?
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1 ATP and 1 GTP
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What is the significance of using energy to add on a CO2 and then take it off using energy in pyr -> PEP?
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Le Chatelier's principle of removing product drives reaction. Also, removing it makes the reaction irreversible.
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What is the regulation of pyr -> PEP?
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pyruvate carboxylase has acetyl CoA (+) as an obligate activator.
PEP carboxykinase regulated positively by glucagon and cortisol which raises gene expression. |
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How does glucagon turn on a gene?
Cortisol? |
turns on the transcription factor: KREB protein
Cortisol receptor is the txn factor that is a Zn finger class receptor. |
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Conversion of F1,6P to F6P.
Regulation. |
Uses F1,6Bisphosphatase
F2,6P negative ATP (+) |
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Conversion G6P to Glc
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G6Pase
Only available in the liver. |
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Where does glycerol come into gluconeogenesis?
Lactate? Alanine? |
converted to 3-GAP
goes into pyruvate also pyruvate |
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How is glycolysis regulated in the exact opposite as gluconeogenesis? 5
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Fat digestion -> High ATP (+) F1,6Pase and (-) PFK-1
High F2,6P (-) F1,6Pase and (+) PFK-1 Insulin (+) and glucagon (-) for PFK-2 glucagon (+) PEP carboxykinase Acetyl CoA (+) pyr carboxylase and (-) PDH |
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What is the diabetic drug that inhibits gluconeogenesis?
What is a side effect? |
Metformin (aka glucophage) by inhibiting pyruvate carboxylase. If you have diabetes and hyperglycemia, the last thing you want is the liver to kick out more glucose to the blood.
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How much energy is used to do gluconeogenesis?
What's net effect then? |
6 ATP equivalents
You lost 4 ATP (2 ATP made during glycolysis) |
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How long does glycogen last in resting states?
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12 hours
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Glycogenolysis and gluconeogenesis occur ____.
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concurrently
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How does FA beta oxidation affect the sugar pathways?
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Makes AcCoA which is a big deal as it
lowers PDH and raises PDH Kinase Raises Pyr Raises Pyr carboxylase and gluconeogenesis |
