Question 1

Glucokinase is a molecular sensor for which molecule?

Accepted Answer

A)  glucose 
B)  lactose 
C)  galactose 
D)  maltose 
A)  glucose 
B)  lactose 
C)  galactose 
D)  maltose

Question 2

What advantage is there to phosphoglycerate kinase having an open and closed configuration?

Accepted Answer

A)  It allows water to be trapped in the active site along with the substrate. 
B)  It forces covalent binding of the substrate to the enzyme active site. 
C)  The induced-fit mechanism maximizes accessibility of active site without sacrificing hydrophobic environment. 
D)  Changing of the configuration of the enzyme makes the reaction exergonic. 
A)  It allows water to be trapped in the active site along with the substrate. 
B)  It forces covalent binding of the substrate to the enzyme active site. 
C)  The induced-fit mechanism maximizes accessibility of active site without sacrificing hydrophobic environment. 
D)  Changing of the configuration of the enzyme makes the reaction exergonic.

Question 3

Predict how oxygen saturation would be affected if an individual has defective hexokinase enzymes.

Accepted Answer

A)  2,3-BPG levels are elevated and oxygen binding decreases. 
B)  2,3-BPG levels are reduced and oxygen binding increases. 
C)  2,3-BPG levels are elevated and oxygen binding increases. 
D)  2,3-BPG levels are reduced and oxygen binding decreases. 
A)  2,3-BPG levels are elevated and oxygen binding decreases. 
B)  2,3-BPG levels are reduced and oxygen binding increases. 
C)  2,3-BPG levels are elevated and oxygen binding increases. 
D)  2,3-BPG levels are reduced and oxygen binding decreases.

Question 4

For the following reaction A$\rightarrow$B, if at equilibrium $\Delta$DG $\degree$'  > 0, what can be said about the directionality of the reaction?

Accepted Answer

A)  strongly favored in the forward direction 
B)  strongly favored in the reverse direction 
C)  strongly favored in both directions 
D)  Not enough information is given. 
A)  strongly favored in the forward direction 
B)  strongly favored in the reverse direction 
C)  strongly favored in both directions 
D)  Not enough information is given.

Question 5

Benedict's test is a redox reaction between glucose and copper. Draw the reaction between glucose and copper.

Accepted Answer

See Figure 9.13a. The glucose

Question 6

When a mixture of glucose 6-phosphate and fructose 6-phosphate is incubated with the enzyme phosphohexose isomerase, the final mixture contains twice as much glucose 6-phosphate as fructose 6-phosphate. Which one of the following statements is MOST correct, when applied to the reaction below (R = 8.315 J/mol·K and T = 298 K)?
Glucose 6-phosphate  $\harr$fructose 6-phosphate

Accepted Answer

A)  "$\Delta$G  '$\degree$ is +1.7 kJ/mol." 
B)  "$\Delta$G  '$\degree$ is -1.7 kJ/mol." 
C)  "$\Delta$G  '$\degree$ is zero." 
D)  "It is not possible to calculate $\Delta$G  '$\degree$" 
A)  "$\Delta$G  '$\degree$ is +1.7 kJ/mol." 
B)  "$\Delta$G  '$\degree$ is -1.7 kJ/mol." 
C)  "$\Delta$G  '$\degree$ is zero." 
D)  "It is not possible to calculate $\Delta$G  '$\degree$"

Question 7

Hexokinase has a Km of 0.1 mM for glucose, whereas glucokinase has a Km of 10 mM for glucose. What does that mean for their relative affinities for glucose?

Accepted Answer

A)  Glucokinase has a higher affinity. 
B)  Hexokinase has a higher affinity. 
C)  Km does not measure affinity. 
D)  They are different enzymes and affinity cannot be compared between enzymes. 
A)  Glucokinase has a higher affinity. 
B)  Hexokinase has a higher affinity. 
C)  Km does not measure affinity. 
D)  They are different enzymes and affinity cannot be compared between enzymes.

Question 8

Which of the following is an energy conversion pathway?

Accepted Answer

A)  urea cycle 
B)  citrate cycle 
C)  nitrogen fixation and assimilation 
D)  fatty acid degradation and synthesis 
A)  urea cycle 
B)  citrate cycle 
C)  nitrogen fixation and assimilation 
D)  fatty acid degradation and synthesis

Question 9

Explain why in the production of beer, the yeast are first grown under aerobic conditions and then shifted to anaerobic conditions.

Accepted Answer

The oxygen is needed for the production

Question 10

Which coenzyme is required to convert glyceraldehyde-3-P into 1,3-bisphosphosphoglycerate?

Accepted Answer

A)  FAD+ 
B)  NAD+ 
C)  ATP 
D)  Pi 
A)  FAD+ 
B)  NAD+ 
C)  ATP 
D)  Pi

Question 11

Demonstrate the cyclization of linear glucose to cyclic glucopyranose.

Accepted Answer

The answer of Demonstrate the cyclization of linear glucose to...

Question 12

What may be the root cause of the slowing of the flux of metabolites through the glycolysis and gluconeogenesis pathways in your body?

Accepted Answer

A)  elevated levels of amino acids in the body 
B)  elevated levels of glycogen in the body 
C)  lowered levels of protein synthesis 
D)  lowered levels of enzyme activity 
A)  elevated levels of amino acids in the body 
B)  elevated levels of glycogen in the body 
C)  lowered levels of protein synthesis 
D)  lowered levels of enzyme activity

Question 13

Galactosemia is deficiency in which enzyme?

Accepted Answer

A)  galactokinase 
B)  galactose-1-P uridyltransferase 
C)  UDP-galactose 4-epimerase 
D)  phosphoglucomutase 
A)  galactokinase 
B)  galactose-1-P uridyltransferase 
C)  UDP-galactose 4-epimerase 
D)  phosphoglucomutase

Question 14

Fructose 1,6-bisphosphate is converted to two products with a standard free energy of 23.8 kJ/mol. Under what condition(s) will this reaction become spontaneous?

Accepted Answer

A)  spontaneous under any conditions 
B)  spontaneous under all conditions 
C)  when there is a high concentration of products relative to the concentration of fructose 1,6-bisphosphate 
D)  when there is a low concentration of products relative to the concentration of fructose 1,6-bisphosphate 
A)  spontaneous under any conditions 
B)  spontaneous under all conditions 
C)  when there is a high concentration of products relative to the concentration of fructose 1,6-bisphosphate 
D)  when there is a low concentration of products relative to the concentration of fructose 1,6-bisphosphate

Question 15

Which of the following is NOT a reason why glycolysis is considered one of the core metabolic pathways in nature?

Accepted Answer

A)  Glycolytic enzymes are hugely conserved among all living organisms. 
B)  It is a primary pathway for ATP generation under anaerobic conditions. 
C)  Metabolites of glycolysis are precursors for a large number of interdependent pathways. 
D)  It is a primary pathway for nitrogen generation. 
A)  Glycolytic enzymes are hugely conserved among all living organisms. 
B)  It is a primary pathway for ATP generation under anaerobic conditions. 
C)  Metabolites of glycolysis are precursors for a large number of interdependent pathways. 
D)  It is a primary pathway for nitrogen generation.

Question 16

Sucrose is a nonreducing sugar. Why?

Accepted Answer

A)  Sucrose does not contain an aldehyde functional group. 
B)  Sucrose does not react with heat. 
C)  Sucrose is a pyranose that cannot be reacted with copper. 
D)  Sucrose is a disaccharide that cannot be converted to an open chain. 
A)  Sucrose does not contain an aldehyde functional group. 
B)  Sucrose does not react with heat. 
C)  Sucrose is a pyranose that cannot be reacted with copper. 
D)  Sucrose is a disaccharide that cannot be converted to an open chain.

Question 17

Fructose-1,6-bisphosphate is cleaved by aldolase. What is required for the reaction to proceed?

Accepted Answer

A)  production of endergonic intermediate 
B)  substrate phosphorylation 
C)  cleaving of high-energy phosphate bond 
D)  formation of Schiff base intermediate 
A)  production of endergonic intermediate 
B)  substrate phosphorylation 
C)  cleaving of high-energy phosphate bond 
D)  formation of Schiff base intermediate

Question 18

Define aldose.

Accepted Answer

A)  Only aldose molecules have CH2OH. 
B)  Aldose molecules have ketone functional groups. 
C)  Aldose molecules have aldehyde functional groups. 
D)  Aldose molecules are all five-membered rings. 
A)  Only aldose molecules have CH2OH. 
B)  Aldose molecules have ketone functional groups. 
C)  Aldose molecules have aldehyde functional groups. 
D)  Aldose molecules are all five-membered rings.

Question 19

Distinguish between the energy investment of stage 1 and stage 2 of glycolysis.

Accepted Answer

In glycolysis the first five r

Question 20

How does phosphoglycerate kinase make glycolysis energy neutral at this step?

Accepted Answer

A)  It uses ATP to produce 3-phosphoglycerate. 
B)  It produces 2 ATP along with 3-phosphoglycerate. 
C)  It results in a reaction at equilibrium. 
D)  It results in a reaction is endergonic. 
A)  It uses ATP to produce 3-phosphoglycerate. 
B)  It produces 2 ATP along with 3-phosphoglycerate. 
C)  It results in a reaction at equilibrium. 
D)  It results in a reaction is endergonic.

Exam 9: Glycolysis: a Paradigm of Metabolic Regulation

Glucokinase is a molecular sensor for which molecule?

What advantage is there to phosphoglycerate kinase having an open and closed configuration?

Predict how oxygen saturation would be affected if an individual has defective hexokinase enzymes.

For the following reaction A →\rightarrow→ B, if at equilibrium Δ\DeltaΔ DG °\degree° ' > 0, what can be said about the directionality of the reaction?

Benedict's test is a redox reaction between glucose and copper. Draw the reaction between glucose and copper.

Hexokinase has a Km of 0.1 mM for glucose, whereas glucokinase has a Km of 10 mM for glucose. What does that mean for their relative affinities for glucose?

Which of the following is an energy conversion pathway?

Explain why in the production of beer, the yeast are first grown under aerobic conditions and then shifted to anaerobic conditions.

Which coenzyme is required to convert glyceraldehyde-3-P into 1,3-bisphosphosphoglycerate?

Demonstrate the cyclization of linear glucose to cyclic glucopyranose.

What may be the root cause of the slowing of the flux of metabolites through the glycolysis and gluconeogenesis pathways in your body?

Galactosemia is deficiency in which enzyme?

Fructose 1,6-bisphosphate is converted to two products with a standard free energy of 23.8 kJ/mol. Under what condition(s) will this reaction become spontaneous?

Which of the following is NOT a reason why glycolysis is considered one of the core metabolic pathways in nature?

Sucrose is a nonreducing sugar. Why?

Fructose-1,6-bisphosphate is cleaved by aldolase. What is required for the reaction to proceed?

Define aldose.

Distinguish between the energy investment of stage 1 and stage 2 of glycolysis.

How does phosphoglycerate kinase make glycolysis energy neutral at this step?

Principles of Biochemistry

Physical Biochemistry: Energy Conversion, Water, and Membranes

Nucleic Acid Structure and Function

Protein Structure

Methods in Protein Biochemistry

Protein Function

Enzyme Mechanisms

Cell Signaling Systems

The Citrate Cycle

Oxidative Phosphorylation

Photosynthesis

Carbohydrate Structure and Function

Carbohydrate Metabolism

Lipid Structure and Function

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Metabolic Integration

DNA Replication, Repair, and Recombination

RNA Synthesis, Processing, and Gene Silencing

Protein Synthesis, Posttranslational Modification, and Transport

Gene Regulation

Filters

For the following reaction A $\rightarrow$ B, if at equilibrium $\Delta$ DG $\degree$ ^' > 0, what can be said about the directionality of the reaction?