Question 1

As the partial pressure of carbon dioxide increases, the affinity of oxygen binding to hemoglobin ______________.

Accepted Answer

The answer of As the partial pressure of carbon dioxide...

Question 2

Which of the following is correct concerning fetal hemoglobin?

Accepted Answer

A)  Fetal hemoglobin is composed of two α and two γ subunits. 
B)  Fetal hemoglobin binds 2,3-BPG more tightly than normal adult hemoglobin. 
C)  Fetal hemoglobin binds oxygen less than HbA at all pO2. 
D)  Fetal hemoglobin does not exist in the T-form. 
E)  None of the answers is correct. 
A)  Fetal hemoglobin is composed of two α and two γ subunits. 
B)  Fetal hemoglobin binds 2,3-BPG more tightly than normal adult hemoglobin. 
C)  Fetal hemoglobin binds oxygen less than HbA at all pO2. 
D)  Fetal hemoglobin does not exist in the T-form. 
E)  None of the answers is correct.

Question 3

In normal adult hemoglobin, HbA, the β6 position is a glutamate residue, whereas in sickle-cell hemoglobin, HbS, it is a ____________ residue.

Accepted Answer

The answer of In normal adult hemoglobin, HbA, the β6...

Question 4

The binding of 2-3-bisphosphogycerate to hemoglobin ____________ (increases, decreases) its affinity of oxygen binding.

Accepted Answer

The answer of The binding of 2-3-bisphosphogycerate to hemoglobin ____________...

Question 5

What is the organic portion of the heme group in hemoglobin?

Accepted Answer

A)  protoporphyrinogen 
B)  protoporphyrin 
C)  uroporphyrinogen 
D)  coproporphyrinogen 
E)  protoheme 
A)  protoporphyrinogen 
B)  protoporphyrin 
C)  uroporphyrinogen 
D)  coproporphyrinogen 
E)  protoheme

Question 6

Which is NOT correct concerning the accepted models that describe cooperative binding?

Accepted Answer

A)  In the sequential model, the binding of a ligand changes the conformation of the subunit to which it binds, in turn inducing a change in neighboring subunits. 
B)  All known allosteric proteins exhibit either the concerted or sequential model exclusive of the other. 
C)  Both models incorporate a low affinity T-state and a higher affinity R-state. 
D)  Both models explain the sigmoid-shaped binding curve. 
E)  In the concerted model, all molecules exist either in the T-state or the R-state. 
A)  In the sequential model, the binding of a ligand changes the conformation of the subunit to which it binds, in turn inducing a change in neighboring subunits. 
B)  All known allosteric proteins exhibit either the concerted or sequential model exclusive of the other. 
C)  Both models incorporate a low affinity T-state and a higher affinity R-state. 
D)  Both models explain the sigmoid-shaped binding curve. 
E)  In the concerted model, all molecules exist either in the T-state or the R-state.

Question 7

Which of the following is the immediate product of the reaction between carbon dioxide and water?

Accepted Answer

A)  HCO2H 
B)  HCO3- 
C)  CO32- 
D)  H2CO3- 
E)  None of the answers is correct. 
A)  HCO2H 
B)  HCO3- 
C)  CO32- 
D)  H2CO3- 
E)  None of the answers is correct.

Question 8

Why is the HbS mutation so prevalent in Africa and other tropical regions?

Accepted Answer

A)  The oxygen binds with greater affinity to the proximal histidine residue of HbS. 
B)  Bonding of carbon dioxide to HbS molecules increases the binding of oxygen. 
C)  Hemoglobin binds more oxygen with the reduction of the hemoglobin S chain. 
D)  Hemoglobin binds more oxygen with aggregations of α chains found in sickle-cell hemoglobin. 
E)  People with sickle-cell trait are resistant to malaria, increasing the prevalence of the HbS allele. 
A)  The oxygen binds with greater affinity to the proximal histidine residue of HbS. 
B)  Bonding of carbon dioxide to HbS molecules increases the binding of oxygen. 
C)  Hemoglobin binds more oxygen with the reduction of the hemoglobin S chain. 
D)  Hemoglobin binds more oxygen with aggregations of α chains found in sickle-cell hemoglobin. 
E)  People with sickle-cell trait are resistant to malaria, increasing the prevalence of the HbS allele.

Question 9

Which of the following is correct concerning the oxygenation plot of proteins X and Y shown below?

Accepted Answer

A)  Protein Y exhibits tighter oxygen-binding than protein X. 
B)  Protein Y corresponds to fetal hemoglobin, and protein X corresponds to normal adult hemoglobin. 
C)  Protein X corresponds to fetal hemoglobin, and protein Y corresponds to normal adult hemoglobin. 
D)  Protein X corresponds to myoglobin, and protein Y corresponds to hemoglobin. 
E)  None of the answers is correct. 
A)  Protein Y exhibits tighter oxygen-binding than protein X. 
B)  Protein Y corresponds to fetal hemoglobin, and protein X corresponds to normal adult hemoglobin. 
C)  Protein X corresponds to fetal hemoglobin, and protein Y corresponds to normal adult hemoglobin. 
D)  Protein X corresponds to myoglobin, and protein Y corresponds to hemoglobin. 
E)  None of the answers is correct.

Question 10

Describe the concerted model to explain allosteric cooperative binding.

Accepted Answer

The protein exists in two conformations:

Question 11

Which of the following represents the most predominant form for the transfer of carbon dioxide in the blood?

Accepted Answer

A)  CO2 
B)  H2CO3 
C)  HCO3- 
D)  CO32- 
E)  None of the answers is correct. 
A)  CO2 
B)  H2CO3 
C)  HCO3- 
D)  CO32- 
E)  None of the answers is correct.

Question 12

Describe how carbon dioxide affects the oxygenation of hemoglobin.

Accepted Answer

Increased levels of carbon dioxide cause

Exam 7: Hemoglobin: a Portrait of a Protein in Action

As the partial pressure of carbon dioxide increases, the affinity of oxygen binding to hemoglobin ______________.

Which of the following is correct concerning fetal hemoglobin?

In normal adult hemoglobin, HbA, the β6 position is a glutamate residue, whereas in sickle-cell hemoglobin, HbS, it is a ____________ residue.

The binding of 2-3-bisphosphogycerate to hemoglobin ____________ (increases, decreases) its affinity of oxygen binding.

What is the organic portion of the heme group in hemoglobin?

Which is NOT correct concerning the accepted models that describe cooperative binding?

Which of the following is the immediate product of the reaction between carbon dioxide and water?

Why is the HbS mutation so prevalent in Africa and other tropical regions?

Which of the following is correct concerning the oxygenation plot of proteins X and Y shown below?

Describe the concerted model to explain allosteric cooperative binding.

Which of the following represents the most predominant form for the transfer of carbon dioxide in the blood?

Describe how carbon dioxide affects the oxygenation of hemoglobin.

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

Enzymes: Basic Concepts and Kinetics

Oxidative Phosphorylation

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

The Light Reactions of Photosynthesis

The Calvin Cycle and the Pentose Phosphate Pathway

Glycogen Metabolism

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