Question 1

Hemoglobin-binding of oxygen is best described as a

Accepted Answer

A)   concerted model.
B)   Michaelis-Menten model.
C)   sequential model.
D)   combination of sequential and concerted models.
E)   None of the answers is correct.

Question 2

What is metmyoglobin?

Accepted Answer

Metmyoglobin is formed when the heme iro...

Question 3

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.

Question 4

What functional role does the "distal histidine" play in the function of myoglobin and hemoglobin?

Accepted Answer

The bonding between the iron and oxygen ...

Question 5

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.

Question 6

Describe the chemical basis of the Bohr effect.

Accepted Answer

The effect observed by Christian Bohr is...

Question 7

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.

Question 8

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 would function as a better oxygen-transport protein than protein X.
C)   Protein X exhibits cooperative binding, whereas Y does not.
D)   Protein Y corresponds to myoglobin, and protein X corresponds to hemoglobin.
E)   Protein X contains multiple binding sites.

Question 9

What is formed when carbon dioxide reacts with the amino terminal group of deoxyhemoglobin?

Accepted Answer

A)   amide
B)   imine
C)   carbonate
D)   carbamate
E)   None of the answers is correct.

Question 10

What is the composition of fetal hemoglobin?

Accepted Answer

A)   two   α\alphaα  chains and two  β\betaβ  chains.
B)   two   α\alphaα  chains and two  γ\gammaγ  chains.
C)   two   α\alphaα  chains and two  β\betaβ  chains
D)   two  α\alphaα  chains and two  δ\deltaδ  chains
E)   four  β\betaβ  chains

Question 11

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 position is...

Question 12

Which of the following is a genetic disease that results from a decreased production of one of the subunits of hemoglobin?

Accepted Answer

A)   thalassemia
B)   pernicious anemia
C)   megaloblastic hereditary anemia
D)   acanthocytosis
E)   aplastic anemia A

Question 13

What oxidized heme protein does not reversibly bind oxygen?

Accepted Answer

A)   metmyoglobin
B)   oxyhemoglobin
C)   carboxyhemoglobin
D)   leghemoglobin
E)   None of the answers is correct.

Question 14

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. B

Question 15

Why is it advantageous for hemoglobin to have allosteric properties?

Accepted Answer

Hemoglobin binds oxygen in a positive cooperative manner.This allows it to become saturated in the lungs,where oxygen pressure is high.When the hemoglobin moves to tissues,the lower oxygen pressure induces it to release oxygen and thus deliver oxygen where it is needed.

Question 16

Sickle-cell anemia is caused by

Accepted Answer

A)   a decreased production of α chains of hemoglobin.
B)   a substitution of a Glu residue for a Phe residue at the β6 position.
C)   the loss of the heme group because the proximal His is oxidized.
D)   a substitution of a Val residue for a Glu residue at the β6 position.
E)   a substitution of Glu residue for His at the C-terminal of the α chain.

Question 17

The ability of myoglobin to bind oxygen depends on the presence of a bound prosthetic group called _____________.

Accepted Answer

The answer of The ability of myoglobin to bind oxygen...

Question 18

Another reason why hemoglobin is sensitive to changes in pH is that the T-state of hemoglobin is stabilized by a salt bridge between β1 Asp 94 and the C-terminal ___________________ of the β1 chain.

Accepted Answer

Question 19

Describe the structure of normal adult hemoglobin.

Accepted Answer

Normal adult hemoglobin,HbA,is a tetrame...

Question 20

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.

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

Hemoglobin-binding of oxygen is best described as a

Correct AnswerverifiedShow Answer

What is metmyoglobin?

Correct AnswerverifiedMetmyoglobin is formed when the heme iro...View AnswerShow Answer

Which of the following is correct concerning fetal hemoglobin?

Correct AnswerverifiedShow Answer

What functional role does the "distal histidine" play in the function of myoglobin and hemoglobin?

Correct AnswerverifiedThe bonding between the iron and oxygen ...View AnswerShow Answer

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

Correct AnswerverifiedShow Answer

Describe the chemical basis of the Bohr effect.

Correct AnswerverifiedThe effect observed by Christian Bohr is...View AnswerShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

What is formed when carbon dioxide reacts with the amino terminal group of deoxyhemoglobin?

Correct AnswerverifiedShow Answer

What is the composition of fetal hemoglobin?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following is a genetic disease that results from a decreased production of one of the subunits of hemoglobin?

Correct AnswerverifiedA

What oxidized heme protein does not reversibly bind oxygen?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedB

Why is it advantageous for hemoglobin to have allosteric properties?

Correct AnswerverifiedHemoglobin binds oxygen in a positive cooperative manner.This allows it to become saturated in the lungs,where oxygen pressure is high.When the hemoglobin moves to tissues,the lower oxygen pressure induces it to release oxygen and thus deliver oxygen where it is needed.

Sickle-cell anemia is caused by

Correct AnswerverifiedShow Answer

The ability of myoglobin to bind oxygen depends on the presence of a bound prosthetic group called _____________.

Correct AnswerverifiedShow Answer

Another reason why hemoglobin is sensitive to changes in pH is that the T-state of hemoglobin is stabilized by a salt bridge between β1 Asp 94 and the C-terminal ___________________ of the β1 chain.

Correct AnswerverifiedShow Answer

Describe the structure of normal adult hemoglobin.

Correct AnswerverifiedNormal adult hemoglobin,HbA,is a tetrame...View AnswerShow Answer

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

Correct AnswerverifiedShow Answer

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Metmyoglobin is formed when the heme iro...
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The bonding between the iron and oxygen ...
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The effect observed by Christian Bohr is...
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Correct Answer
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A

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B

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Hemoglobin binds oxygen in a positive cooperative manner.This allows it to become saturated in the lungs,where oxygen pressure is high.When the hemoglobin moves to tissues,the lower oxygen pressure induces it to release oxygen and thus deliver oxygen where it is needed.

Correct Answer
verified

Correct Answer
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Another reason why hemoglobin is sensitive to changes in pH is that the T-state of hemoglobin is stabilized by a salt bridge between β₁ Asp 94 and the C-terminal ___________________ of the β1 chain.

Correct Answer
verified

Correct Answer
verified
Normal adult hemoglobin,HbA,is a tetrame...
View Answer

Correct Answer
verified