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11 Cards in this Set
- Front
- Back
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Where is lactate made?
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erythrocytes or anaerobic muscles
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What are some glucose precursors in animals?
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-lactate
-pyruvate -glycerol -most amino acids, except leucine and lysine |
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Describe the Cori cycle
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-Muscle cells break down glucose to lactate and release ATP (glycolysis)
-lactate is transported to liver where it is used to make glucose using ATP (gluconeogenesis) and is sent to muscle to form glycogen |
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Where does gluconeogenesis mainly occur?
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liver
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In what cells and where in the cell is glucose 6-phophatase located?
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-hepatocytes and renal cells
-inside surface of ER |
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What is the first control point of gluconeogenesis?
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-decide whether or not pyruvate will undergo citric acid cycle or gluconeogenesis
-Acetyl-CoA is positive allosteric modulator for pyruvate carboxylase so promotes gluconeogenesis -Acetyl-CoA is a negative allosteric modulator for pyruvate dehydrogenase complex so inhibits citric acid cycle progression |
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What is second control point of glycolysis vs. gluconeogenesis? Describe extracellular regulation (hormonal)
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-PFK-1 vs. FBP-1
-regulated by [fructose 2,6-bisphosphate] which is converted from F6P by PFK-2 (reverse by FBP-2) -F26BP increased activity of PFK-2 and inhibited activity of FBP-2 -insulin activates PFK-2 and deactivates FBP-2 via dephosphorylating by phosphoprotein phosphatase, so more F26BP and glycolysis -glucagon and cAMP activates FBP-2 via phosphorylation via PKA, so low F26BP and gluconeogenesis |
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What is the second control point of glycolysis vs. gluconeogenesis? Describe intracellular regulation
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-PFK-1 vs. FBP-1
-AMP inhibits activity of FBP-1 -ATP and citrate inhibits activity of PFK-1 -AMP and ADP increase activity of PFK-1 -these molecules are all positive or negative allosteric modulators |
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How is PEP carboxykinase regulated?
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-FOX01 is transcription factor for PEP carboxykinase (gluconeogenesis)
-insulin binds to receptor -activates PKB -PKB phosphorylates FOX01 which targets it for ubiquitin tagging for destruction in cytosol, so no protein, no gluconeogenesis -glucagon prevents phosphorylation of FOX01 by PKB -unphosphorylated FOX01 goes into nucleus and binds to DNA to transcribe mRNA and get PEP carboxykinase |
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What reaction does pyruvate carboxylase catalyze and what other molecules does it need?
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-pyruvate --> oxaloacetate in mitochondria
-ATP, biotin, and CO2 |
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What reaction does PEP carboxykinase catalyze and what molecules does it need in the mitochondria?
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-oxaloacetate-->PEP
-Uses GTP in mitochondria |
