Term
|
Definition
Glucose -----> Glucose-6-phospate
a) Mg2+ and Hexokinase
b) ATP---->ADP |
|
|
Term
|
Definition
Glucose-6-phosphate------> Fructose-6-phospate
a) Phosphoglucose isomerase (REVERSIBLE) |
|
|
Term
|
Definition
Fructose-6-phosphate ------> Fructose 1,6 bisphosphate
a) Mg2+ and Phosphofructokinase
b) ATP---> ADP
RATE DETERMINING |
|
|
Term
|
Definition
glyceraldehyde-3-phosphate + dihydroxyacentonephosphate ----> Triose phosphate isomerase (catalyticaly perfect enzyme)
REVERSIBLE |
|
|
Term
|
Definition
| Two ATP molecules are consumed. |
|
|
Term
|
Definition
Glyceraldehyde-3-phosphate ----? 1,3 Bisphosphoglycerate
a) Glyceraldehyde-3-phosphate dehydrogenase
b) Pi + NAD+ ---> NADH + H+
REVERSIBLE |
|
|
Term
|
Definition
1,3 Bisphosphoglycerate ----> 3-Phosphoglycerate
a) Phosphoglycerate kinase and Mg2+
b) ADP---->ATP
REVERSIBLE |
|
|
Term
|
Definition
3-Phosphoglycerate ----> 2-Phosphoglycerate
a) Phosphoglycerate mutase
REVERSIBLE |
|
|
Term
|
Definition
2-Phosphoglycerate ----> Phosphoenolpyruvate
a) Enolase and Mg2+
b) Yields 1 Water
REVERSIBLE
|
|
|
Term
Why there is a need to convert 2PG to PEP?
|
|
Definition
Must be converted to PEP to form a high energy intermediate that is able to synthesize. Releases a large amount of energy.
|
|
|
Term
|
Definition
Phosphoenolpyruvate ----> Pyruvate
a) Mg2+ and K+ and Pyruvate Kinase
b) ADP ----> ATP
|
|
|
Term
| What is the net production of ATP per glucose molecule? |
|
Definition
|
|
Term
| Under aerobic conditions pyruvate is oxidized into? |
|
Definition
CO2 and H2O.
CITRIC ACID CYCLE |
|
|
Term
| Under anaerobic conditions in muscle pyruvate is converted into? |
|
Definition
|
|
Term
| Under anaerobic conditions in yeast pyruvate is converted into? |
|
Definition
|
|
Term
| Anaerobic glycolysis in Muscle equation: |
|
Definition
| Glucose + 2ADP + 2Pi ----> 2 lactate + 2ATP + 2H2O + 2H+ |
|
|
Term
|
Definition
An essential cofactor of Pyruvate decarboxylase.
Binds tightly but noncovalently. |
|
|
Term
|
Definition
|
|
Term
| What is the structure of PFK? |
|
Definition
| Is a tetrameric enzyme with two conformational states R and T that are at equillibrium. PFK has two binding sites and inhibitor and substrate site. |
|
|
Term
| Galactose is converted into? |
|
Definition
Glucose-6-Phosphate
(4steps) |
|
|
Term
| Step #1 Galactose conversion: |
|
Definition
| Galactose is phophorylated at C1 by ATP in a reaction catalyzed by galactokinase. |
|
|
Term
| Step #2 galactose conversion: |
|
Definition
Galactose-1- phosphate uridylyl transferase transfers the uridylyl group of UDP-glucose to galactose-1-phosphate to yield glucose-1-phosphate (G1P) and UDP-galactose by the reversible cleavage of UDP-glucose's pyrophosphoryl bond.
|
|
|
Term
| Step #3 Galactose conversion: |
|
Definition
| UDP-Galactose-4-epimerase converts UDP-galactose back to UDP-glucose. This enzyme is associated NAD+, which suggests that the reaction involves the sequential oxidation and reduction of the hexose C4 atom. |
|
|
Term
| Step #4 Galactose conversion: |
|
Definition
| G1P is converted to the glycolytic intermediate G6P by the action of phosphoglucomutase. |
|
|
Term
| Conversion of Mannose into Glycolysis: |
|
Definition
Mannose ---> Mannose-6-phosphate ---> Fructose-6-phosphate
a) ATP-->ADP (Hexokinase)
b) Phosphomannose isomerase |
|
|
Term
| The Pentose Phosphate Pathway: |
|
Definition
| 3G6P + 6NADP+ + 3H2O ---> 6NADPH + 6H+ + 3CO2 + 2F6P + GAP |
|
|
Term
| What is the metabolic importance of regulating flux through the pyruvate kinase reaction? |
|
Definition
| Pyruvate kinase regulation is important for controlling the flux of metabolites, such as fructose (in liver), which enter glycolysis after the PFK step. |
|
|
Term
| What is the advantage of activating pyruvate kinase with fructose-1,6-bisphosphate? |
|
Definition
| FBP is the product of the reaction 3 of glycolysis, so it acts as a feed-forward activator of the enxyme that catalyzes step 10. This regulatory mechanism ensures that following 6 step in equilibrium are "pulled" into completion. |
|
|
Term
| Is there and energetic benefit of Glucose over Fructose? |
|
Definition
| No both produce the same amount of ATP. |
|
|
Term
| Is there an energetic benefit of Glucose over Mannose? |
|
Definition
| No both produce the same amount of ATP. |
|
|
Term
| In an erythrocyte undergoing glycolysis, what will be the effect of sudden increase in concetration of ATP? |
|
Definition
| ATP will inhibit glycolysis (PFK) |
|
|
Term
| In an erythrocyte undergoing glycolysis, what will be the effect of sudden increase in concetration of AMP? |
|
Definition
| AMP will stimulate glycolysis (PFK & PK) |
|
|
Term
| In an erythrocyte undergoing glycolysis, what will be the effect of sudden increase in concetration of G6P? |
|
Definition
| G6P will inhibit glycolysis (Hexokinase) |
|
|
Term
| In an erythrocyte undergoing glycolysis, what will be the effect of sudden increase in concetration of F1,6BP? |
|
Definition
| F1,6BP will stimulate glycolysis (PFK) |
|
|
Term
| In an erythrocyte undergoing glycolysis, what will be the effect of sudden increase in concetration of Citrate? |
|
Definition
| Citrate will inhibit glycolysis (PFK) |
|
|
Term
| Glycogen breakdown requires three enzymes: |
|
Definition
a) Glycogen Phosphorylase
b) Glycogen debranching enzyme
c) Phosphoglucomutase |
|
|
Term
|
Definition
| Catalyzes glycogen phosphorolysis to yield glucose-1-phosphate(G1P). The enzyme releases a glucose unit only if it is at least five units away from a branch point |
|
|
Term
| Glycogen debranching enzyme: |
|
Definition
| Removes glycogen's branches, thereby making additional glucose residues accessible to glycogen phosphorylase. |
|
|
Term
|
Definition
| Converts G1P to G6P, which has several metabolic fates. |
|
|
Term
| Reacion mechanism of glycogen phosphorylase: |
|
Definition
a) The formation of an E Pi glycogen ternary complex.
b)Shielded oxonium ion intermediate formation.
c) Reaction of Pi with oxonium ion with overall rentention of config. about C1. |
|
|
Term
| Phosphoglucomutase Mechanism: |
|
Definition
a) The OH group at C6 of G1P attacks the phosphoenzyme to form a dephosphenzyme-G1, 6P intermediate.
b) The ser OH group on the dephosphoenzyme attacks the phosphoryl group at C1 to regenerate the phosphoenzyme with the formation of G6P. |
|
|
Term
| Three enzymes that participate in glycogen synthesis are: |
|
Definition
1) UDP-glucose pyrophosphorylase.
2) Glycogen synthase.
3) Glycogen branching enzyme. |
|
|
Term
| Glycogen Synthesis steps: |
|
Definition
1) UDP-Glucose Pyrophosphorylase activates glucosyl units.
2) Glycogen Synthase extends glycogen chains.
3)Branching enzyme catalyses transfer and alpha 1-->4 bond formation. |
|
|
Term
| The mechanism of Phosphoglucomutase: |
|
Definition
1) The OH group at C6 of G1P attacks the phosphoenzyme to form a dephosphoenzyme-G1,6P intermediate.
2) The Ser OH group on the dephosphoenzyme attacks the phosphoryl groups at the C1 to regenerate the phosphenzyme with the formation of G6P. |
|
|
Term
|
Definition
| Is and exergonic process that is a reverse process that uses UTP to generate UDP-glucose intermediate. |
|
|
Term
| Glycogen synthesis steps: |
|
Definition
1) UDP-glucose Pyrophosphorylase activates glucosyl units.
2) Glycogen synthase extends glycogen chains.
3) Branching enzyme catalyses transfer and alpha 1-->4 bond formation. |
|
|
Term
| How is a new molecule of glycogen started? |
|
Definition
| Glycogenin attaches from UDP-glucose to a Tyr residue on a protein and catalyzes extension to up to 7 glucose residues to make a primer. Glycogen synthase continues extending and branching enzymes introduces branch points. |
|
|
Term
| The binding of Epinephrine to liver and muscle cell receptors....... |
|
Definition
| Increases intracellular cAMP and cytosolic Ca2+ levels which promotes glycogen degradation. |
|
|
Term
| When glucose is plentiful....... |
|
Definition
| Insulin stimulate glucose uptake and glycogen synthesis in muscle cells. |
|
|
Term
| In the liver when glucose levels are high..... |
|
Definition
| Glycogen synthesis is increased. |
|
|
Term
|
Definition
| Is activated by Ca2+ and the phosphorylation of its Alpha and Beta subunits by PKA. |
|
|
Term
| The conversion of pyruvate into phosphoenolpyruvate by: |
|
Definition
| Pyruvate carboxylase and PEP carboxykinase. |
|
|
Term
| The citric acid cycles main reason for existance is: |
|
Definition
| To break acetyl groups down by oxidation into CO2. |
|
|
Term
| Citric Acid cycle balanced equation: |
|
Definition
| 3NAD+ + FAD + GDP + Pi + acetyl-CoA ----> 3NADH +FADH2 + GTP + CoA + 2CO2 |
|
|
Term
| Acetyl CoA's ____ bond is high in energy. |
|
Definition
|
|
Term
|
Definition
| Consumed in the first step of the citric acid cycle and regenerated in the last step of the cycle . |
|
|
Term
| Pyruvate Dehydrogenase Complex reaction: |
|
Definition
| Pyruvate + CoA + NAD+ ---> acetyl-CoA + CO2 + NADH |
|
|
Term
|
Definition
| an essential cofactor of pyruvate decarboxylase (Alcoholic fermentation in yeast) |
|
|
Term
| Step #1 pyruvate dehydrogenase complex: |
|
Definition
| 1) Pyruvate dehydrogenase (E1), a TPP-requiring enzyme, decarboxylates pyruvate with the formation of a hydroxyethyl-TPP intermediate. |
|
|
Term
| Step #2 pyruvate dehydrogenase complex: |
|
Definition
| 2) The hydroxyethyle group is transferred to the next enzyme, (E2) which contains a lipoamide group. The hydroxyethyl group derived from pyruvate attacks the lipoamide disulfide, and TPP is eliminated. |
|
|
Term
| Step #3 pyruvate dehydrogenase complex: |
|
Definition
| E2 then catalyzes a transesterification reaction in which the acetyl group is transferred to CoA, yielding acetyl-CoA and dihydrolipoamide-E2. |
|
|
Term
| Step #4 Pyruvate Dehydrogenase complex: |
|
Definition
| Acetyl CoA has now been formed, but the lioamide group E2 must be regenerated. E3 reoxidizes dihydrolioamide to complete the ctalytic cycle of E2. |
|
|
Term
| Step #5 Pyruvate Dehydrogenase complex: |
|
Definition
| Reduced E3 is reoxidized. The Sulfhydryl groups are reoxidized by a mechanism in which FAD funnels electrons to NAD+ yielding NADH. |
|
|
