Term
2 conditions under which metabolism of glucose can occur |
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Definition
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Term
How is metabolism of glucose different in the liver than in the muscles/brain? |
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Definition
liver = storage
muscles/brain = form ATP |
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Term
What happens when there are high glucose levels? |
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Definition
glucose entry into liver & pancreas |
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Term
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Definition
energy by catabolism of glucose |
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Term
Does glycolysis occur under aerobic or anaerobic conditions? |
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Definition
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Term
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Definition
"preparatory phase"; energy invested to form activated sugars |
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Term
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Definition
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Term
Is the reaction catalyzed by phosphohexose isomerase in glycolysis thermodynamically favorable or unfavorable? |
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Definition
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Term
What is the major regulatory step of glycolysis? |
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Definition
phosphofructokinase (PFK) catalyzing the 2nd phosphorylation step --> fructose 1,6-bisphosphate |
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Term
What is the only product formed by aldolase that can continue on in glycolysis? |
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Definition
glyceraldehyde 3-phosphate |
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Term
What is the end of the prep phase of glycolysis? |
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Definition
formation of 2 glyceraldehyde 3-phosphate molecules |
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Term
What type of catalysis is used by glyceraldehyde 3-phosphate dehydrogenase to convert GAP to 1,3-bisphosphoglycerate in glycolysis? |
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Definition
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Term
What mechanism does phosphoglycerate kinase (PGK) use to make ATP in glycolysis? |
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Definition
substrate level phosphorylation |
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Term
Does phosphoglycerate mutase create a molecule with a higher or lower energy potential in glycolysis? |
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Definition
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Term
What type of reaction does enolase perform to make 2-PG --> PEP in glycolysis? |
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Definition
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Term
What type of reaction is catalyzed by pyruvate kinase (PK) in glycolysis? |
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Definition
the second substrate level phosphorylation |
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Term
net reaction of glycolysis |
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Definition
1 glucose + 2 ADP + 2 Pi + 2 NAD+ --> 2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O |
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Term
Cells oxidize pyruvate to generate ______. |
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Definition
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Term
Under anaerobic conditions, animal tissues undergo ______ to regenerate NAD+. |
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Definition
fermentation of pyruvate --> lactate |
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Term
What must happen to dietary sugars in order for them to by metabolized? |
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Definition
they must be converted to glucose or glycolysis intermediates |
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Term
What is the role of glycolysis in muscle? |
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Definition
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Term
How many steps are there at which glycolysis is regulated in muscle? |
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Definition
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Term
How does hexokinase regulate glycolysis in muscle? |
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Definition
allosterically inhibited by glucose 6-phosphate |
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Term
What is the most important control site for glycolysis in muscle? |
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Definition
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Term
When does PFK activity for glycolysis in muscle increase? |
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Definition
when ATP/AMP ratio decreases |
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Term
How does pyruvate kinase regulate glycolysis in muscle? |
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Definition
allosterically inhibited by ATP |
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Term
What is the point of glycolysis regulation in the liver? |
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Definition
the liver works to maintain blood glucose levels |
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Term
What is the primary enzyme for formation of glucose-6-phosphate in the liver? |
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Definition
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Term
How does liver PFK regulate glycolysis? |
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Definition
energy charge & citrate (the first product of the citric acid cycle) |
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Term
How does liver pyruvate kinase regulate glycolysis? |
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Definition
allosterically but also by covalent modification |
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Term
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Definition
process of making new glucose from lactate, pyruvate, & non-carbohydrate precursors |
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Term
How do you make gluconeogenesis favorable? |
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Definition
counter exergonic (irreversible) glycolysis steps |
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Term
How many steps does it take to convert pyruvate to PEP in gluconeogenesis? |
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Definition
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Term
fructose-1,6-bisphosphatase (AKA FBP-ase1) (gluconeogenesis) |
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Definition
catalyzes conversion of fructose-1,6-bisphosphate --> fructose-6-phosphate |
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Term
glucose-6-phosphate (gluconeogenesis) |
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Definition
hydrolyzes glucose 6-phosphate to form glucose & orthophosphate (inorganic phosphate) |
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Term
net reaction of gluconeogenesis |
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Definition
2 pyruvate + 4 ATP + 2 GTP + 2 NADH + 4 H2O --> glucose + 4 ADP + 2 GDP + 6 Pi + 2 NAD+ + 2H+ |
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Term
When do glycolysis & gluconeogenesis work together? |
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Definition
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Term
What is the final product of glycolysis? |
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Definition
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Term
What catalyzes the conversion of pyruvate --> acetyl-CoA? |
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Definition
pyruvate dehydrogenase complex |
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Term
3 enzyme components for PDH complex |
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Definition
1. E1 2. E2 (a trimer) 3. E3 (a dimer) |
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Term
6 step reaction sequence for the PDH complex |
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Definition
1. pyruvate binds covalently to TPP cofactor of E1 & becomes decarboxylated 2. E1 transfers hydroxyethyl group from E1 to lipoamide cofactor 3. lipoamide arm with thioacetate swings into active site of E2 4. E2 transfers acetyl group from lipoamide --> coenzyme A 5. E3 oxidizes lipoamide of E2 6. E3 oxidizes FADH2 |
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