Question 1

Glycogen synthase catalyzes the transfer of a glucose residue from UDP-glucose to one of the _____________ ends of glycogen.

Accepted Answer

The answer of Glycogen synthase catalyzes the transfer of a...

Question 2

Why is the T state of glycogen phosphorylase less active?

Accepted Answer

A)  The adjacent amino acids are not phosphorylated, and thus the catalysis cannot be carried out. 
B)  The active site is partially blocked. 
C)  ATP cannot be bound by the T state. 
D)  Glucose-1-phosphate remains bound to the active site. 
E)  None of the answers is correct. 
A)  The adjacent amino acids are not phosphorylated, and thus the catalysis cannot be carried out. 
B)  The active site is partially blocked. 
C)  ATP cannot be bound by the T state. 
D)  Glucose-1-phosphate remains bound to the active site. 
E)  None of the answers is correct.

Question 3

What are the fates of the glucose-1-phosphate derived from glycogen?

Accepted Answer

It is 1)converted into glucose-6-phospha

Question 4

What liver enzyme catalyzes the hydrolysis of a phosphate group to produce glucose?

Accepted Answer

A)  glucose phosphorylase 
B)  glucose-1-phosphatase 
C)  glucose-4-phosphatase 
D)  glucose-6-phosphatase 
E)  None of the answers is correct. 
A)  glucose phosphorylase 
B)  glucose-1-phosphatase 
C)  glucose-4-phosphatase 
D)  glucose-6-phosphatase 
E)  None of the answers is correct.

Question 5

Why can't the glucose 1-phosphate diffuse out of the cell?

Accepted Answer

There is no membrane transport

Question 6

What is the normal glucose concentration in blood?

Accepted Answer

A)  80-120 g/100 mL (4.4-6.7 M) 
B)  8-12 g/100 mL (0.44-0.67 M) 
C)  80-120 mg/100 mL (4.4-6.7 mM) 
D)  80-120 $\mu$g/100 mL (4.4-6.7  $\mu$M) 
E)  None of the answers is correct. 
A)  80-120 g/100 mL (4.4-6.7 M) 
B)  8-12 g/100 mL (0.44-0.67 M) 
C)  80-120 mg/100 mL (4.4-6.7 mM) 
D)  80-120 $\mu$g/100 mL (4.4-6.7  $\mu$M) 
E)  None of the answers is correct.

Question 7

Phosphorylase kinase becomes fully active by being phosphorylated and binding ___________.

Accepted Answer

The answer of Phosphorylase kinase becomes fully active by being...

Question 8

What protein is the $\delta$ subunit of phosphorylase kinase?

Accepted Answer

A)  protein kinase A 
B)  phosphorylase 
C)  adenylate cyclase 
D)  protein phosphatase 1 
E)  calmodulin 
A)  protein kinase A 
B)  phosphorylase 
C)  adenylate cyclase 
D)  protein phosphatase 1 
E)  calmodulin

Question 9

Which of the following serves as the glucose "sensor" enzyme in liver cells?

Accepted Answer

A)  glucose-6-phosphatase 
B)  hexokinase 
C)  phosphoglucomutase 
D)  UDP-glucose pyrophosphorylase 
E)  phosphorylase a 
A)  glucose-6-phosphatase 
B)  hexokinase 
C)  phosphoglucomutase 
D)  UDP-glucose pyrophosphorylase 
E)  phosphorylase a

Question 10

What path in addition to the cAMP-induced signal transduction is used in the liver to stimulate glycogen breakdown by epinephrine?

Accepted Answer

In the liver,epinephrine also binds to a

Question 11

Draw a structure showing the most common linkage between glucose units found in glycogen.

Accepted Answer

The structure should

Question 12

Thermodynamically,the reaction glucose-1-phosphate + UTP   UDP-glucose + PPiis readily reversible.Explain why the formation of UDP-glucose from glucose-1-phosphate and UTP is essentially irreversible.

Accepted Answer

The hydrolysis of pyrophosphate (PP_i)to t

Question 13

What type of glycosidic bond is found at the branch points of glycogen?

Accepted Answer

A)  $\alpha$-1,2 
B)  $\alpha$-1,4 
C)  $\alpha$-1,6 
D)  $\beta$-1,4 
E)  $\beta$-1,6 
A)  $\alpha$-1,2 
B)  $\alpha$-1,4 
C)  $\alpha$-1,6 
D)  $\beta$-1,4 
E)  $\beta$-1,6

Question 14

In skeletal muscle,the binding of ___________ converts phosphorylase b into the active form.

Accepted Answer

The answer of In skeletal muscle,the binding of ___________ converts...

Question 15

What is the function of liver glycogen degradation?

Accepted Answer

A)  For glucose export to other tissues when glucose levels are low 
B)  To maintain glucose levels after a large meal 
C)  To provide for the large energy needs of the liver 
D)  To allow for synthesis of lipids 
E)  None of the answers is correct. 
A)  For glucose export to other tissues when glucose levels are low 
B)  To maintain glucose levels after a large meal 
C)  To provide for the large energy needs of the liver 
D)  To allow for synthesis of lipids 
E)  None of the answers is correct.

Question 16

What reaction cleaves a bond by the addition of orthophosphate?

Accepted Answer

A)  phosphorolysis 
B)  phosphatase 
C)  transphosphorylation 
D)  oxidative phosphorylation 
E)  None of the answers is correct. 
A)  phosphorolysis 
B)  phosphatase 
C)  transphosphorylation 
D)  oxidative phosphorylation 
E)  None of the answers is correct.

Question 17

What is the activated form of glucose required for glycogen synthesis?

Accepted Answer

A)  glucose-6-phosphate 
B)  glucose-1-phosphate 
C)  ADP-glucose 
D)  UDP-glucose 
E)  GDP-glucose 
A)  glucose-6-phosphate 
B)  glucose-1-phosphate 
C)  ADP-glucose 
D)  UDP-glucose 
E)  GDP-glucose

Question 18

What is the primary glycosidic bond found in glycogen?

Accepted Answer

A)  $\alpha$-1,3 
B)  $\alpha$-1,4 
C)  $\alpha$-1,6 
D)  $\beta$-1,4 
E)  $\beta$-1,6 
A)  $\alpha$-1,3 
B)  $\alpha$-1,4 
C)  $\alpha$-1,6 
D)  $\beta$-1,4 
E)  $\beta$-1,6

Question 19

What hormone signifies the starved state?

Accepted Answer

A)  insulin 
B)  glucagon 
C)  epinephrine 
D)  cortisol 
E)  None of the answers is correct. 
A)  insulin 
B)  glucagon 
C)  epinephrine 
D)  cortisol 
E)  None of the answers is correct.

Question 20

Insulin stimulates glycogen synthase by inactivating ________________________.

Accepted Answer

glycogen s

Exam 21: Glycogen Metabolism

Glycogen synthase catalyzes the transfer of a glucose residue from UDP-glucose to one of the _____________ ends of glycogen.

Why is the T state of glycogen phosphorylase less active?

What are the fates of the glucose-1-phosphate derived from glycogen?

What liver enzyme catalyzes the hydrolysis of a phosphate group to produce glucose?

Why can't the glucose 1-phosphate diffuse out of the cell?

What is the normal glucose concentration in blood?

Phosphorylase kinase becomes fully active by being phosphorylated and binding ___________.

What protein is the δ\deltaδ subunit of phosphorylase kinase?

Which of the following serves as the glucose "sensor" enzyme in liver cells?

What path in addition to the cAMP-induced signal transduction is used in the liver to stimulate glycogen breakdown by epinephrine?

Draw a structure showing the most common linkage between glucose units found in glycogen.

Thermodynamically,the reaction glucose-1-phosphate + UTP UDP-glucose + PPiis readily reversible.Explain why the formation of UDP-glucose from glucose-1-phosphate and UTP is essentially irreversible.

What type of glycosidic bond is found at the branch points of glycogen?

In skeletal muscle,the binding of ___________ converts phosphorylase b into the active form.

What is the function of liver glycogen degradation?

What reaction cleaves a bond by the addition of orthophosphate?

What is the activated form of glucose required for glycogen synthesis?

What is the primary glycosidic bond found in glycogen?

What hormone signifies the starved state?

Insulin stimulates glycogen synthase by inactivating ________________________.

Biochemistry: An Evolving Science

Protein Composition and Structure

Exploring Proteins and Proteomes

DNA, RNA, and the Flow of Genetic Information

Exploring Genes and Genomes

Exploring Evolution and Bioinformatics

Hemoglobin: a Portrait of a Protein in Action

Enzymes: Basic Concepts and Kinetics

Catalytic Strategies

Regulatory Strategies

Carbohydrates

Lipids and Cell Membranes

Membrane Channels and Pumps

Signal-Transduction Pathways

Metabolism: Basic Concepts and Design

Glycolysis and Gluconeogenesis

The Citric Acid Cycle

Oxidative Phosphorylation

The Light Reactions of Photosynthesis

The Calvin Cycle and the Pentose Phosphate Pathway

Fatty Acid Metabolism

Protein Turnover and Amino Acid Catabolism

The Biosynthesis of Amino Acids

Nucleotide Biosynthesis

Biosynthesis of Membrane Lipids and Steroids

The Integration of Metabolism

DNA Replication, repair, and Recombination

RNA Synthesis and Processing

Protein Synthesis

The Control of Gene Expression in Prokaryotes

The Control of Gene Expression in Eukaryotes

Sensory Systems

The Immune System

Molecular Motors

Drug Development

Filters

What protein is the $\delta$ subunit of phosphorylase kinase?

Thermodynamically,the reaction glucose-1-phosphate + UTP UDP-glucose + PP_iis readily reversible.Explain why the formation of UDP-glucose from glucose-1-phosphate and UTP is essentially irreversible.