Question 1

All species can make glucose from two-carbon or three-carbon precursors.

Accepted Answer

A) True 
 B)False

Question 2

Glycogen phosphorylase is more, less) active when phosphorylated, and it is activated, inhibited) by glucose 6-phosphate.

Accepted Answer

A)  more; activated 
B)  less; activated 
C)  more; inhibited 
D)  less; inhibited 
A)  more; activated 
B)  less; activated 
C)  more; inhibited 
D)  less; inhibited

Question 3

Glucose 1-phosphate formed by glycogen degradation is converted to glucose 6-phosphate by phosphoglucomutase. Why is this beneficial?

Accepted Answer

A)  Glucose 6-phosphate is more stable. 
B)  Glucose 6-phosphate is converted to free glucose. 
C)  Glucose 6-phosphate is an intermediate in several pathways, including glycolysis. 
D)  Glucose 6-phosphate can be transported to the liver. 
E)  All of the above 
A)  Glucose 6-phosphate is more stable. 
B)  Glucose 6-phosphate is converted to free glucose. 
C)  Glucose 6-phosphate is an intermediate in several pathways, including glycolysis. 
D)  Glucose 6-phosphate can be transported to the liver. 
E)  All of the above

Question 4

Two molecules of NADPH are generated for each molecule of glucose 6-phosphate that enters the pentose phosphate pathway.

Accepted Answer

A) True 
 B)False

Question 5

Which substance is not needed for the conversion of glucose to fructose?

Accepted Answer

A)  NADPH 
B)  Aldose reductase 
C)  QH2  
D)  NAD+ 
A)  NADPH 
B)  Aldose reductase 
C)  QH2  
D)  NAD+

Question 6

Deficiencies in G6PDH glucose-6-phosphate dehydrogenase) in humans causes

Accepted Answer

A)  varying degrees of hemolytic anemia. 
B)  increased resistance to malaria. 
C)  lack of NADPH in many cells. 
D)  All of the above 
E)  A and B 
A)  varying degrees of hemolytic anemia. 
B)  increased resistance to malaria. 
C)  lack of NADPH in many cells. 
D)  All of the above 
E)  A and B

Question 7

The major regulatory step of the pentose phosphate pathway is catalyzed by which enzyme?

Accepted Answer

A)  transaldolase 
B)  phosphofructokinase-1 
C)  glucose 6-phosphate dehydrogenase 
D)  ribose 5-phosphate isomerase 
A)  transaldolase 
B)  phosphofructokinase-1 
C)  glucose 6-phosphate dehydrogenase 
D)  ribose 5-phosphate isomerase

Question 8

During fasting, what role does gluconeogenesis play?

Accepted Answer

A)  Aids in the release of glucose from stored glycogen in the liver. 
B)  Uses alanine to restore blood glucose levels. 
C)  Produces products that slow the oxidation of pyruvate. 
D)  Helps transport glucose across the blood-brain barrier to maintain brain glucose levels. 
A)  Aids in the release of glucose from stored glycogen in the liver. 
B)  Uses alanine to restore blood glucose levels. 
C)  Produces products that slow the oxidation of pyruvate. 
D)  Helps transport glucose across the blood-brain barrier to maintain brain glucose levels.

Question 9

The enzyme for the key regulatory step in glycogen biosynthesis is

Accepted Answer

A)  glycogen synthase. 
B)  glycogenin. 
C)  branching enzyme. 
D)  phosphoglucomutase. 
E)  UDP-glucose pyrophosphorylase. 
A)  glycogen synthase. 
B)  glycogenin. 
C)  branching enzyme. 
D)  phosphoglucomutase. 
E)  UDP-glucose pyrophosphorylase.

Question 10

The pentose phosphate pathway can alternatively be called the pentose phosphate cycle because is a net product of the pathway that can be recycled.

Accepted Answer

A)  glucose 6-phosphate 
B)  NADP+ 
C)  carbon dioxide 
D)  phosphate 
E)  UDP 
A)  glucose 6-phosphate 
B)  NADP+ 
C)  carbon dioxide 
D)  phosphate 
E)  UDP

Question 11

Which is a reasonable concentration for glucose in the blood?

Accepted Answer

A)  5 μM 
B)  5 mM 
C)  50 mM 
D)  5 M 
A)  5 μM 
B)  5 mM 
C)  50 mM 
D)  5 M

Question 12

Glycogen synthesis in vertebrates requires to activate glucose 1-phosphate.

Accepted Answer

A)  ATP 
B)  ADP 
C)  UTP 
D)  UDP 
E)  All of the above 
A)  ATP 
B)  ADP 
C)  UTP 
D)  UDP 
E)  All of the above

Question 13

Glucose is stored as in bacteria and animals.

Accepted Answer

A)  glucagons 
B)  starch 
C)  glycogen 
D)  NADPH 
A)  glucagons 
B)  starch 
C)  glycogen 
D)  NADPH

Question 14

Gluconeogenesis is the .

Accepted Answer

A)  result of amylase activity 
B)  formation of glycogen 
C)  formation of starches 
D)  formation of glucose from simple two and three-carbon precursors 
E)  formation of glucose from other carbohydrates 
A)  result of amylase activity 
B)  formation of glycogen 
C)  formation of starches 
D)  formation of glucose from simple two and three-carbon precursors 
E)  formation of glucose from other carbohydrates

Question 15

Fructose 2,6-bisphosphate glycolysis while it gluconeogenesis.

Accepted Answer

A)  stimulates; stimulates 
B)  stimulates; inhibits 
C)  inhibits; stimulates 
D)  inhibits; inhibits 
A)  stimulates; stimulates 
B)  stimulates; inhibits 
C)  inhibits; stimulates 
D)  inhibits; inhibits

Question 16

The activity of phosphoenolpyruvate carboxykinase PEPCK) is most affected by

Accepted Answer

A)  glucagon concentration. 
B)  insulin concentration. 
C)  the level of PEPCK gene transcription. 
D)  the elevation of cAMP concentration on fasting. 
A)  glucagon concentration. 
B)  insulin concentration. 
C)  the level of PEPCK gene transcription. 
D)  the elevation of cAMP concentration on fasting.

Question 17

At high glucagon concentrations gluconeogenesis will be favored over glycolysis.

Accepted Answer

A) True 
 B)False

Question 18

Glycerol is converted to when it is used for gluconeogenesis.

Accepted Answer

A)  dihydroxyacetone phosphate 
B)  phosphoenolpyruvate 
C)  oxaloacetate 
D)  3-phosphoglycerate 
A)  dihydroxyacetone phosphate 
B)  phosphoenolpyruvate 
C)  oxaloacetate 
D)  3-phosphoglycerate

Question 19

Which is not a function of the main products of the pentose phosphate pathway?

Accepted Answer

A)  To maintain the reduced form of iron in hemoglobin. 
B)  To provide reducing power for the synthesis of fatty acids. 
C)  To serve as precursors in the biosynthesis of RNA and DNA. 
D)  To raise the concentration of cAMP. 
A)  To maintain the reduced form of iron in hemoglobin. 
B)  To provide reducing power for the synthesis of fatty acids. 
C)  To serve as precursors in the biosynthesis of RNA and DNA. 
D)  To raise the concentration of cAMP.

Question 20

Fragments containing three carbons can be transferred from a ketose phosphate to an aldose phosphate by the enzyme .

Accepted Answer

A)  pyruvate carboxylase 
B)  transaldolase 
C)  debranching enzyme 
D)  ribose-5-phosphate isomerase 
A)  pyruvate carboxylase 
B)  transaldolase 
C)  debranching enzyme 
D)  ribose-5-phosphate isomerase

Exam 12: Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

All species can make glucose from two-carbon or three-carbon precursors.

Glycogen phosphorylase is more, less) active when phosphorylated, and it is activated, inhibited) by glucose 6-phosphate.

Glucose 1-phosphate formed by glycogen degradation is converted to glucose 6-phosphate by phosphoglucomutase. Why is this beneficial?

Two molecules of NADPH are generated for each molecule of glucose 6-phosphate that enters the pentose phosphate pathway.

Which substance is not needed for the conversion of glucose to fructose?

Deficiencies in G6PDH glucose-6-phosphate dehydrogenase) in humans causes

The major regulatory step of the pentose phosphate pathway is catalyzed by which enzyme?

During fasting, what role does gluconeogenesis play?

The enzyme for the key regulatory step in glycogen biosynthesis is

The pentose phosphate pathway can alternatively be called the pentose phosphate cycle because is a net product of the pathway that can be recycled.

Which is a reasonable concentration for glucose in the blood?

Glycogen synthesis in vertebrates requires to activate glucose 1-phosphate.

Glucose is stored as in bacteria and animals.

Gluconeogenesis is the .

Fructose 2,6-bisphosphate glycolysis while it gluconeogenesis.

The activity of phosphoenolpyruvate carboxykinase PEPCK) is most affected by

At high glucagon concentrations gluconeogenesis will be favored over glycolysis.

Glycerol is converted to when it is used for gluconeogenesis.

Which is not a function of the main products of the pentose phosphate pathway?

Fragments containing three carbons can be transferred from a ketose phosphate to an aldose phosphate by the enzyme .

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

Dna Replication, Repair, and Recombination

Transcription and Rna Processing

Protein Synthesis

Recombinant Dna Technology

Filters