Question 1

Generally speaking, the same mechanisms that activate glycogen phosphorylase will turn off glycogen synthase.

Accepted Answer

A) True 
 B)False

Question 2

Gluconeogenesis is the synthesis of

Accepted Answer

A)  glucose from non-carbohydrate precursors 
B)  glycogen from glucose 
C)  pyruvate from glucose 
D)  fatty acids from glucose 
E)  glucose from glycogen 
A)  glucose from non-carbohydrate precursors 
B)  glycogen from glucose 
C)  pyruvate from glucose 
D)  fatty acids from glucose 
E)  glucose from glycogen

Question 3

Starting from glucose and UTP and ATP, how many high-energy bonds are broken/consumed to add that glucose to a glycogen molecule?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  The answer cannot be determined form the information given. 
A)  1 
B)  2 
C)  3 
D)  4 
E)  The answer cannot be determined form the information given.

Question 4

In the Cori cycle

Accepted Answer

A)  lactic acid is transported from the liver to muscle by the blood. 
B)  lactic acid is transported from the liver to the kidneys by the blood. 
C)  glycolysis takes place in muscle and gluconeogenesis in the liver. 
D)  glycolysis takes place in the liver and gluconeogenesis in muscle. 
E)  none of these 
A)  lactic acid is transported from the liver to muscle by the blood. 
B)  lactic acid is transported from the liver to the kidneys by the blood. 
C)  glycolysis takes place in muscle and gluconeogenesis in the liver. 
D)  glycolysis takes place in the liver and gluconeogenesis in muscle. 
E)  none of these

Question 5

The enzyme glucose-6-phosphatase is only found in cells which have this function or ability:

Accepted Answer

A)  Ability to utilize glucose anaerobically. 
B)  Ability to replenish the levels of glucose in the blood. 
C)  Glycogen storage. 
D)  Ability to produce lactic acid as an end product of metabolism. 
E)  Glucose-6-phosphatase activity is found in almost all types of cells. 
A)  Ability to utilize glucose anaerobically. 
B)  Ability to replenish the levels of glucose in the blood. 
C)  Glycogen storage. 
D)  Ability to produce lactic acid as an end product of metabolism. 
E)  Glucose-6-phosphatase activity is found in almost all types of cells.

Question 6

Which of the following mechanisms can be used to regulate metabolic pathways?

Accepted Answer

A)  Allosteric activators and inhibitors. 
B)  Covalent modifications of enzymes. 
C)  Use of separate enzymes at a given point in the forward and backward pathways. 
D)  Regulation of the genes for the enzymes used in the pathway. 
E)  All of these are used to regulate metabolism. 
A)  Allosteric activators and inhibitors. 
B)  Covalent modifications of enzymes. 
C)  Use of separate enzymes at a given point in the forward and backward pathways. 
D)  Regulation of the genes for the enzymes used in the pathway. 
E)  All of these are used to regulate metabolism.

Question 7

How are the branches in glycogen produced?

Accepted Answer

A)  A branching enzyme catalyses the addition of a single glucose unit via an α(1,6) bond to glycogen from a glucose-1-phosphate, releasing Pi. 
B)  A branching enzyme catalyses the addition of a single glucose unit via an α(1,6) bond to glycogen from a glucose-6-phosphate, releasing Pi. 
C)  A branching enzyme catalyses the addition of a single glucose unit via an α(1,6) bond to glycogen from a glucose-UDP, releasing UDP. 
D)  A branching enzyme moves a short chain of several glucose units from a linear α(1,4) section of glycogen to make a new α(1,6) branch point. 
A)  A branching enzyme catalyses the addition of a single glucose unit via an α(1,6) bond to glycogen from a glucose-1-phosphate, releasing Pi. 
B)  A branching enzyme catalyses the addition of a single glucose unit via an α(1,6) bond to glycogen from a glucose-6-phosphate, releasing Pi. 
C)  A branching enzyme catalyses the addition of a single glucose unit via an α(1,6) bond to glycogen from a glucose-UDP, releasing UDP. 
D)  A branching enzyme moves a short chain of several glucose units from a linear α(1,4) section of glycogen to make a new α(1,6) branch point.

Question 8

The process called substrate cycling is used to describe this process:

Accepted Answer

A)  Freely reversible reactions. 
B)  Recycling of vitamins as catalysts in metabolism 
C)  Situations where there are two different enzymes used to reverse a specific step in a metabolic pathway. 
D)  Metabolic pathways which run in cycles and regenerate the initial molecule. 
E)  None of these answers describes substrate cycling. 
A)  Freely reversible reactions. 
B)  Recycling of vitamins as catalysts in metabolism 
C)  Situations where there are two different enzymes used to reverse a specific step in a metabolic pathway. 
D)  Metabolic pathways which run in cycles and regenerate the initial molecule. 
E)  None of these answers describes substrate cycling.

Question 9

Glycogen synthase and glycogen phosphorylase

Accepted Answer

A)  are modified by the same enzymes 
B)  are not subject to allosteric control 
C)  are not subject to covalent modification 
D)  none of these 
A)  are modified by the same enzymes 
B)  are not subject to allosteric control 
C)  are not subject to covalent modification 
D)  none of these

Question 10

When glycogen synthase is phosphorylated

Accepted Answer

A)  its activity decreases. 
B)  its activity increases. 
C)  its activity is unaffected. 
D)  none of these because that enzyme doesn't get phosphorylated. 
A)  its activity decreases. 
B)  its activity increases. 
C)  its activity is unaffected. 
D)  none of these because that enzyme doesn't get phosphorylated.

Question 11

Which of the following hormone's main function is to raise the level of blood glucose?

Accepted Answer

A)  epinephrine 
B)  insulin 
C)  glucagon 
D)  none of these raises blood glucose 
A)  epinephrine 
B)  insulin 
C)  glucagon 
D)  none of these raises blood glucose

Question 12

How many ATP equivalents are expended to convert 2 pyruvates to 1 glucose?

Accepted Answer

A)  2 
B)  4 
C)  6 
D)  8 
A)  2 
B)  4 
C)  6 
D)  8

Question 13

The liver contains a special enzyme, hexokinase, to act as a backup for glucokinase when the glucose levels in the body get very high.

Accepted Answer

A) True 
 B)False

Question 14

Which enzyme is used in gluconeogenesis, but NOT in glycolysis?

Accepted Answer

A)  PEP carboxykinase 
B)  enolase 
C)  phosphohexose isomerase 
D)  3-phosphoglycerate dehydrogenase 
A)  PEP carboxykinase 
B)  enolase 
C)  phosphohexose isomerase 
D)  3-phosphoglycerate dehydrogenase

Question 15

The enzyme that catalyzes the interconversion of glucose-1-phosphate and glucose-6-phosphate is

Accepted Answer

A)  a hydrolase. 
B)  a phosphorylase. 
C)  a mutase. 
D)  a dehydrogenase. 
E)  an epimerase 
A)  a hydrolase. 
B)  a phosphorylase. 
C)  a mutase. 
D)  a dehydrogenase. 
E)  an epimerase

Question 16

If an individual lacked the debranching enzyme, the effect would be:

Accepted Answer

A)  the individual could not make glycogen 
B)  the individual could make glycogen but not store it 
C)  the individual would not be able to utilize any glucose from glycogen 
D)  the individual would not be able to completely break down a glycogen molecule 
E)  none of these 
A)  the individual could not make glycogen 
B)  the individual could make glycogen but not store it 
C)  the individual would not be able to utilize any glucose from glycogen 
D)  the individual would not be able to completely break down a glycogen molecule 
E)  none of these

Question 17

Hemolytic anemia is associated with the pentose phosphate pathway because:

Accepted Answer

A)  a deficiency of this pathway leads to a lack of NADPH in red blood cells 
B)  NADPH is required to reduce glutathione 
C)  Red blood cells have minimal resources for maintaining an oxidative balance 
D)  all of these 
A)  a deficiency of this pathway leads to a lack of NADPH in red blood cells 
B)  NADPH is required to reduce glutathione 
C)  Red blood cells have minimal resources for maintaining an oxidative balance 
D)  all of these

Question 18

There is as much energy used to add a phosphate group by means of phosphorolysis, as the energy required adding a phosphate using ATP.

Accepted Answer

A) True 
 B)False

Question 19

It is impossible to reverse any kinase reaction under physiological conditions.

Accepted Answer

A) True 
 B)False

Question 20

In general, opposing pathways, such as glycolysis and gluconeogenesis are not exact reversals of each other.

Accepted Answer

A) True 
 B)False

Exam 18: Storage Mechanisms and Control in Carbohydrate Metabolism

Generally speaking, the same mechanisms that activate glycogen phosphorylase will turn off glycogen synthase.

Gluconeogenesis is the synthesis of

Starting from glucose and UTP and ATP, how many high-energy bonds are broken/consumed to add that glucose to a glycogen molecule?

In the Cori cycle

The enzyme glucose-6-phosphatase is only found in cells which have this function or ability:

Which of the following mechanisms can be used to regulate metabolic pathways?

How are the branches in glycogen produced?

The process called substrate cycling is used to describe this process:

Glycogen synthase and glycogen phosphorylase

When glycogen synthase is phosphorylated

Which of the following hormone's main function is to raise the level of blood glucose?

How many ATP equivalents are expended to convert 2 pyruvates to 1 glucose?

The liver contains a special enzyme, hexokinase, to act as a backup for glucokinase when the glucose levels in the body get very high.

Which enzyme is used in gluconeogenesis, but NOT in glycolysis?

The enzyme that catalyzes the interconversion of glucose-1-phosphate and glucose-6-phosphate is

If an individual lacked the debranching enzyme, the effect would be:

Hemolytic anemia is associated with the pentose phosphate pathway because:

There is as much energy used to add a phosphate group by means of phosphorolysis, as the energy required adding a phosphate using ATP.

It is impossible to reverse any kinase reaction under physiological conditions.

In general, opposing pathways, such as glycolysis and gluconeogenesis are not exact reversals of each other.

Biochemistry and the Organization of Cells

Water: the Solvent for Biochemical Reactions

Amino Acids and Peptides

The Three-Dimensional Structure of Proteins

Protein Purification and Characterization Techniques

The Behavior of Proteins: Enzymes

The Behavior of Proteins: Enzymes, Mechanisms, and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids: How Structure Conveys Information

Biosynthesis of Nucleic Acids: Replication

Transcription of the Genetic Code: Biosynthesis of RNA

Protein Synthesis: Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses, Cancer, and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism: Cellular Signaling

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