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QUESTION 1 1. For Questions #1-7, consider the glycolytic pathway as illustrated

ID: 303404 • Letter: Q

Question

QUESTION 1

1.    For Questions #1-7, consider the glycolytic pathway as illustrated in Figure 14-2 of Lehninger (6th ed.). Each individual step is indicated within answer choices by the enzyme which catalyzes that step.  For each question, select any/all answer choices that apply.

QUESTION:  Under typical cellular conditions, this step is highly exergonic and therefore tightly regulated within our cells.

A.

Hexokinase

B.

phosphohexose isomerase

C.

phosphofructokinase-1

D.

aldolase

E.

phosphoglycerate kinase

F.

phosphoglycerate mutase

  

QUESTION 2

1.    For Questions #1-7, consider the glycolytic pathway as illustrated in Figure 14-2 of Lehninger (6th ed.). Each individual step is indicated within answer choices by the enzyme which catalyzes that step.  For each question, select any/all answer choices that apply.

QUESTION:  This step is part of the "payoff phase" of glycolysis because ATP is generated during this step.

A.

hexokinase

B.

phosphohexose isomerase

C.

phosphofructokinase-1

D.

aldolase

E.

phosphoglycerate kinase

F.

phosphoglycerate mutase

QUESTION 3

1.    For Questions #1-7, consider the glycolytic pathway as illustrated in Figure 14-2 of Lehninger (6th ed.). Each individual step is indicated within answer choices by the enzyme which catalyzes that step.  For each question, select any/all answer choices that apply.

QUESTION:  This step involves intramolecular rearrangements.

A.

hexokinase

B.

phosphohexose isomerase

C.

phosphofructokinase-1

D.

aldolase

E.

phosphoglycerate kinase

F.

phosphoglycerate mutase

QUESTION 4

1.    For Questions #1-7, consider the glycolytic pathway as illustrated in Figure 14-2 of Lehninger (6th ed.). Each individual step is indicated within answer choices by the enzyme which catalyzes that step.  For each question, select any/all answer choices that apply.

QUESTION:  This step is highly endergonic under standard biochemical conditions.

A.

hexokinase

B.

phosphohexose isomerase

C.

phosphofructokinase-1

D.

aldolase

E.

phosphoglycerate kinase

F.

phosphoglycerate mutase

QUESTION 5

1.    For Questions #1-7, consider the glycolytic pathway as illustrated in Figure 14-2 of Lehninger (6th ed.). Each individual step is indicated within answer choices by the enzyme which catalyzes that step.  For each question, select any/all answer choices that apply.

QUESTION:  This step represents a substrate-level phosphorylation.

A.

hexokinase

B.

phosphohexose isomerase

C.

phosphofructokinase-1

D.

aldolase

E.

phosphoglycerate kinase

F.

phosphoglycerate mutase

  

QUESTION 6

1.    For Questions #1-7, consider the glycolytic pathway as illustrated in Figure 14-2 of Lehninger (6th ed.). Each individual step is indicated within answer choices by the enzyme which catalyzes that step.  For each question, select any/all answer choices that apply.

QUESTION:  This step represents a phosphoryl group transfer.

A.

hexokinase

B.

phosphohexose isomerase

C.

phosphofructokinase-1

D.

aldolase

E.

phosphoglycerate kinase

F.

phosphoglycerate mutase

QUESTION 7

1.    For Questions #1-7, consider the glycolytic pathway as illustrated in Figure 14-2 of Lehninger (6th ed.). Each individual step is indicated within answer choices by the enzyme which catalyzes that step.  For each question, select any/all answer choices that apply.

QUESTION:  Under typical cellular conditions, this step is close to equilibrium and therefore readily reversible.

A.

hexokinase

B.

phosphohexose isomerase

C.

phosphofructokinase-1

D.

aldolase

E.

phosphoglycerate kinase

F.

phosphoglycerate mutase

A.

Hexokinase

B.

phosphohexose isomerase

C.

phosphofructokinase-1

D.

aldolase

E.

phosphoglycerate kinase

F.

phosphoglycerate mutase

(a) Preparatory phase Phosphorylation of glucose and its conversion to glyceraldehyde 3-phosphate Glucose ?? ?? first priming reaction ADPhexokinase Glucose 6-phosphate ?-?-?? ?? Fructose 6-phosphate ??? second priming reaction O-O-CH2 Fructose 1,6-bisphosphate cleavage of 6-carbon sugar phosphate to two 3-carbon sugar phosphates ?? ?? Glyceraldehyde 3-phosphate Dihydroxyacetone phosphate (0-0-CH2-C-CHOH triose phosphate (b) Payoff phase (2) Glyceraldehyde(2)-o Oxidative conversion of g?yceraldehyde 3-phosphate to pyruvate and the coupled formation of ATP and NADH -CH-CH 3-phosphate g?yceraldehyde 3-phosphate 2NAD+ oxidation and phosphorylation 2 NADH+ 2H deydrogenase (2) 1,3-Bisphosphoglycerate first ATP-forming reaction (substrate-level phosphorylation) phosphoglycerate 2 ATP kinase (2) 3-Phosphoglycerate (2)D-0-CH2 phosphoglycerate mutase (2) CH2CH- (2) 2-Phosphoglycerate (2) CH2 c- (2) Phosphoenolpyruvate second ATP-forming reaction (substrate-level phosphorylation) 2ADPpyruvate 2 ATP (2) CH- (2) Pyruvate 142 The two phases of glycolysis. For each molecule of glu the preparatory phase (a), two molecules of phase and four ATP are produced in the payoff phase, giving a pyruvate. The r of two ATP per molecule of glucose converted to f reaction steps correspond to the numbered headings in the te

Explanation / Answer

1. the correct answer is "C" (Phosphofructokinase-1).

in the phosphorylation( glycolysis-step 3) fructose 6-phosphate is phosphorylated by ATP to fructose 1,6-bisphosphate. the prefix bis- in bisphosphate means that two separate monophosphate groups are present, whereas the prefix di-means that two phosphate groups are present and are connected by an anhydride bond. this irreversible reaction is catalyzed by an allosteric enzyme phosphofructokinase-1. the high energy phosphate on carbon one is subsequently donated to ADP to produce ATP. this synthesis ATP is called substrate-level phosphorylation because ADP phosphorylation is coupled with the exergonic breakdown of high energy bond.

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2. the correct answer is " E" (phosphoglycerate kinase)

in the step-7 of glycolysis, high energy phosphate group is transferred from 1,3-bisphosphoglycerate to ADP. the formation of ATP is reffered to as substrate-level phosphorylation because the phosphate donor, 1,3-bisphosphoglycerate, is a substrate with high phosphoryl-transfer potential. this step is catalyzed by enzyme "phosphoglycerate kinase".

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3. the correct answer is " B" (phosphohexose isomerase).

(note: actually the correct option is "phosphoglucoisomerase", not phosphohexose isomerase )

in Isomerization step, a readily reversible rearrangement of the chemical structure (isomerization) moves the carboxyl oxygen from carbon 1 to carbon 2, forming a ketose from an aldose sugar. thus, the isomerization of glucose 6-phosphate to fructose 6-phosphate is a conversion of an aldose into a ketose.

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4. the correct answer is "A" (hexokinase"

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5. the correct answer is "E" (phosphoglycerate kinase)

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6. the correct answer is "E" (phosphoglycerate kinase)

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7. the correct answer is "B" (phosphoglucose isomerase)

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