Term
| where does gluconeogensis occur |
|
Definition
| the liver, unless there has been prolonged fasting then the kidney helps |
|
|
Term
| how long can glycogen storage in the liver sustain you |
|
Definition
|
|
Term
| once the liver glycogen storage is depeleted, what kicks in to keep you going |
|
Definition
|
|
Term
| what is the challenge for the body in completing gluconeogenesis |
|
Definition
| need to reverse the three irreversible steps in glycolysis |
|
|
Term
| what are the substrates for gluconeogenesis |
|
Definition
| glycerol, lactate, amino acids |
|
|
Term
| how is glycerol involved in gluconeogenesis |
|
Definition
| adipocytes release FA by hydrolyzing TAG which also releases glycerol. it is converted to DHAP which can go into gluconeogenesis skipping the pyruvate challenge reaction |
|
|
Term
| why can we just keep using glycerol / gluconeogenesis for energy |
|
Definition
| there itsnt enough to give significant energy |
|
|
Term
| where is lactate produced |
|
Definition
| RBC and exercising skeletal muscle |
|
|
Term
| what can convert lactate to pyruvate |
|
Definition
|
|
Term
|
Definition
| lactate made in muscle travels to the liver. gluconeogenesis turns into into glucose, glucose travels to the muscle and is turned into lactate. rinse and repeat |
|
|
Term
| where are amino acids derived from |
|
Definition
|
|
Term
| what is the major amino acid that energy comes from |
|
Definition
|
|
Term
| what needs to happen to amino acids before they can be used for energy |
|
Definition
|
|
Term
| how many amino acids can be used for energy |
|
Definition
|
|
Term
| how are amino acids used for energy |
|
Definition
| they become TCA cycle intermediates which can yeild oxaloacetate which can turn into PEP which can be used in gluconeogenesis |
|
|
Term
| how is acetyl CoA used in glucoenogenesis |
|
Definition
| it isnt, you cannot convert acetyl CoA into pyruvate, PDH is irreversible |
|
|
Term
| how can actyl CoA provide energy if it canot go into gluconeogenesis |
|
Definition
| fatty acid oxidation gives the liver energy to complete gluconeogenesis |
|
|
Term
| what is the first step of gluconeogenesis, what catalyzes it |
|
Definition
| pyruvate to oxaloacetate via pyruvate carboxylase and biotin coenzyme |
|
|
Term
| where does the first step of gluconeogenesis take place |
|
Definition
|
|
Term
| where is pyruvate carboxylase located |
|
Definition
| in cells that dont do gluconeogenesis well (muscle) and need to replace TCA intermediates instead |
|
|
Term
| once produced via gluconeogenesis, what is the fate of oxaloacetate |
|
Definition
| TCA intermediate or further gluconeogenesis |
|
|
Term
|
Definition
| bind CO2 in pyruvate carboxylase |
|
|
Term
| what does pyruvate carboxykinase need to work |
|
Definition
|
|
Term
| what is thee malate shuttle |
|
Definition
| oxaloacetate is converted to malate and back to OAA to get through the mitochondrial membrane in gluconeogenesis |
|
|
Term
| what does OAA turn into if going through gluconeogenesis, what enzyme does it |
|
Definition
| malate via mitochondrial malate dehydrogenase |
|
|
Term
| after going through the membrane what does malate turn into in gluconeogenesis, using what enzyme? |
|
Definition
| OAA via cytosolic malate dehydrogenase |
|
|
Term
| after getting through the mitochondrial membrane, what does OAA turn into, what is needed for this reaction to occur |
|
Definition
|
|
Term
| what enzyme turns OAA into PEP |
|
Definition
|
|
Term
| in glycolysis PEP is turned into pyruvate, why does this not just happen after we reverse it in gluconeogenesis |
|
Definition
| because the enzyme that converts PEP to pyruvate, pyruvate kinase, is inhibited by glycogen |
|
|
Term
| what stimulates pyruvate carboxykinase |
|
Definition
|
|
Term
| what enzyme converts fructose-1,6-bisphosphate into fructose-6-phosphate |
|
Definition
| fructose-1,6-bisphosphatase |
|
|
Term
| what activates fructose-1,6-bisphosphatase, what does this indicate physiologically |
|
Definition
| ATP, the liver needs energy |
|
|
Term
| what inhibits fructose-1,6-bisphosphatase |
|
Definition
| AMP, fructose-2,6-bisphosphate |
|
|
Term
| explain how fructose-2,6-bisphosphate inhibits fructose-1,6-bisphosphatase |
|
Definition
| fructose-2,6-bisphosphate gets low glycolysis will shut off and gluconeogenesis will be able to turn on |
|
|
Term
| how does glycogen affect fructose-1,6-bisphosphatase |
|
Definition
| it inhibits PFK-2 which decreases fructose-2,6-bisphosphate and increases glucoenogenesis and decreases glycolysis |
|
|
Term
| what turns glucose-6-phosphate into glucose |
|
Definition
|
|
Term
| what is used in glyconeolysis to yield free glucose |
|
Definition
|
|
Term
| once productd via gluconeogenesis, where does glucose go |
|
Definition
| out of the liver into the blood to supply tissues |
|
|
Term
| what is the cause of von gierke disease |
|
Definition
| glucose-6-phosphatase deficience |
|
|
Term
| how does substrate avability regulate gluconeogenesis: muscle |
|
Definition
| muscle breaks down into amino acid and its sent to the liver and gluconeogenesis is stimulated by aa. |
|
|
Term
| how does substrate avability regulate gluconeogenesis: fatty acids |
|
Definition
| fatty acid oxidation yields ATP and NADH which go to the liver. this stimulates gluconeogenesis |
|
|
Term
| how do the reversible reactions regulate gluconeogenesis |
|
Definition
| direction of the reactions depend on substrate vs product regulation |
|
|
Term
| how does acetyl CoA regulate gluconeogenesis |
|
Definition
| it allosterically activates pyruvate carboxykinase. if it builds up there isnt enough OAA for it to combine with to make citrate so it activates gluconeogenesis. it inhibits PDH so pyruvate is used for gluconeogenesis so more acetyl CoA isnt made. |
|
|
Term
| how does AMP regulate gluconeogenesis |
|
Definition
| allosterically inhibits fructose-1,6-bisphosphate, it activates PRK 1 and makes sure enzymes are muturally exclusive |
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