Question 1

Which molecule binds MOST strongly to the heme iron?

Accepted Answer

A)   N2
B)   O2
C)   CO2
D)   CO
E)   H2OF) A) and B)
G) A) and C)

Question 2

Which part of the IgG molecule is NOT involved in binding to an antigen?

Accepted Answer

A)   Fab
B)   Fc
C)   heavy chain
D)   light chain
E)   variable domainF) B) and E)
G) B) and C)

Question 3

For the binding of a ligand to a protein, what is the relationship between the Ka (association constant), the Kd (dissociation constant), and the affinity of the protein for the ligand?

Accepted Answer

The relationship between the association...

Question 4

Antibodies against a specific antigen can be injected into a person to provide passive immunity. For which reason is this NOT as effective as the process of vaccination with that antigen?

Accepted Answer

A)   Injection of antibodies does not provide long-lasting immunity.
B)   Vaccination with antigens triggers a clonal selection of B cells and cytotoxic T cells.
C)   Injection of antibodies may cause allergic reactions, while vaccination never causes allergic reactions.
D)   Injection of antibodies does not provide long-lasting immunity, and vaccination with antigens triggers a clonal selection of B cells and cytotoxic T cells.
E)   Injection of antibodies does not provide long-lasting immunity and may cause allergic reactions, while vaccination never causes allergic reactions.F) A) and D)
G) None of the above

Question 5

Which statement about protein-ligand binding is CORRECT?

Accepted Answer

A)   The Ka is equal to the concentration of ligand when all of the binding sites are occupied.
B)   The Ka is independent of such conditions as salt concentration and pH.
C)   The larger the Ka (association constant) , the weaker the affinity.
D)   The larger the Ka, the faster is the binding.
E)   The larger the Ka, the smaller the Kd (dissociation constant) .F) A) and D)
G) B) and C)

Question 6

What is the role of ATP and ATP hydrolysis in the cycle of actin-myosin association and disassociation that leads to muscle contraction?

Accepted Answer

ATP (adenosine triphosphate) plays a cru...

Question 7

(a) What is the effect of pH on the binding of oxygen to hemoglobin (the Bohr Effect)? (b) Briefly describe the mechanism of this effect.

Accepted Answer

(a) The effect of pH on the binding of o...

Question 8

Which statement is NOT correct concerning 2,3-bisphosphoglycerate (BPG) ?

Accepted Answer

A)   It binds at a distance from the heme groups of hemoglobin.
B)   It binds with lower affinity to fetal hemoglobin than to adult hemoglobin.
C)   It increases the affinity of hemoglobin for oxygen.
D)   It is an allosteric modulator.
E)   It is normally found associated with the hemoglobin extracted from red blood cells.F) A) and B)
G) B) and D)

Question 9

Explain why most multicellular organisms use an iron-containing protein for oxygen binding rather than free Fe2+. Your answer should include an explanation of (a) the role of heme and (b) the role of the protein itself.

Accepted Answer

Most multicellular organisms use an iron...

Question 10

Which antibody is principally found in saliva, tears, and breast milk?

Accepted Answer

A)   IgA
B)   IgD
C)   IgE
D)   IgG
E)   IgMF) A) and E)
G) None of the above

Question 11

The Fab regions of an antibody are made of which protein chain?

Accepted Answer

A)   a light chain containing variable and constant regions
B)   a heavy chain containing variable and constant regions
C)   a heavy chain containing only constant regions
D)   both a light chain and a heavy chain containing variable and constant regions
E)   both a light chain containing variable and constant regions and a heavy chain containing only constant regionsF) A) and B)
G) All of the above

Question 12

Describe briefly the two principal models for the cooperative binding of ligands to proteins with multiple binding sites.

Accepted Answer

The two principal models for the coopera...

Question 13

Which statement is NOT correct concerning cooperative binding of a ligand to a protein?

Accepted Answer

A)   It is usually a form of allosteric interaction.
B)   It is usually associated with proteins with multiple subunits.
C)   It rarely occurs in enzymes.
D)   It results in a nonlinear Hill Plot.
E)   It results in a sigmoidal binding curve.F) B) and C)
G) D) and E)

Question 14

The fundamental cause of sickle-cell disease is a change in the structure of:

Accepted Answer

A)   blood.
B)   capillaries.
C)   hemoglobin.
D)   red cells.
E)   the heart.F) B) and E)
G) B) and D)

Question 15

Which class of proteins includes the LARGEST polypeptide chains discovered to date in humans?

Accepted Answer

A)   myosins
B)   actins
C)   titins
D)   troponins
E)   globinsF) C) and D)
G) D) and E)

Question 16

A test where antibodies are used to quantitatively detect the presence of antiviral antibodies in human blood samples is referred to as:

Accepted Answer

A)   Western blot.
B)   ELISA.
C)   Northern blot.
D)   FRET.
E)   PCR.F) A) and C)
G) A) and D)

Question 17

Which immune-system cells are responsible for producing antibodies?

Accepted Answer

A)   macrophages
B)   B cells
C)   helper T cells
D)   cytotoxic T cells
E)   erythrocytesF) A) and E)
G) D) and E)

Question 18

Explain briefly why the relative affinity of heme for oxygen and carbon monoxide is changed by the presence of the myoglobin protein.

Accepted Answer

The relative affinity of heme for oxygen...

Question 19

During muscle contraction, the _____ of myofibrils contract and the _____ move closer together due to the movement of myosin thick filaments along actin thin filaments.

Accepted Answer

A)   Z disks; A bands
B)   A bands; M lines
C)   I bands; Z disks
D)   I bands; M lines
E)   M lines; I bandsF) C) and D)
G) A) and E)

Question 20

Describe the cycle of actin-myosin association and disassociation that leads to muscle contraction.

Accepted Answer

The cycle of actin-myosin association an...

Exam 5: Protein Function

What is the role of ATP and ATP hydrolysis in the cycle of actin-myosin association and disassociation that leads to muscle contraction?

Correct AnswerAnswered by ExamLex AIATP (adenosine triphosphate) plays a cru...View AnswerShow Answer

During muscle contraction, the _____ of myofibrils contract and the _____ move closer together due to the movement of myosin thick filaments along actin thin filaments.

Correct AnswerverifiedShow Answer

Which immune-system cells are responsible for producing antibodies?

Correct AnswerverifiedShow Answer

Describe briefly the two principal models for the cooperative binding of ligands to proteins with multiple binding sites.

Correct AnswerAnswered by ExamLex AIThe two principal models for the coopera...View AnswerShow Answer

Which antibody is principally found in saliva, tears, and breast milk?

Correct AnswerverifiedShow Answer

Which part of the IgG molecule is NOT involved in binding to an antigen?

Correct AnswerverifiedShow Answer

Which molecule binds MOST strongly to the heme iron?

Correct AnswerverifiedShow Answer

For the binding of a ligand to a protein, what is the relationship between the Ka (association constant), the Kd (dissociation constant), and the affinity of the protein for the ligand?

Correct AnswerAnswered by ExamLex AIThe relationship between the association...View AnswerShow Answer

Explain briefly why the relative affinity of heme for oxygen and carbon monoxide is changed by the presence of the myoglobin protein.

Correct AnswerAnswered by ExamLex AIThe relative affinity of heme for oxygen...View AnswerShow Answer

Which class of proteins includes the LARGEST polypeptide chains discovered to date in humans?

Correct AnswerverifiedShow Answer

Which statement is NOT correct concerning 2,3-bisphosphoglycerate (BPG) ?

Correct AnswerverifiedShow Answer

Antibodies against a specific antigen can be injected into a person to provide passive immunity. For which reason is this NOT as effective as the process of vaccination with that antigen?

Correct AnswerverifiedShow Answer

Which statement about protein-ligand binding is CORRECT?

Correct AnswerverifiedShow Answer

Explain why most multicellular organisms use an iron-containing protein for oxygen binding rather than free Fe2+. Your answer should include an explanation of (a) the role of heme and (b) the role of the protein itself.

Correct AnswerAnswered by ExamLex AIMost multicellular organisms use an iron...View AnswerShow Answer

The Fab regions of an antibody are made of which protein chain?

Correct AnswerverifiedShow Answer

Describe the cycle of actin-myosin association and disassociation that leads to muscle contraction.

Correct AnswerAnswered by ExamLex AIThe cycle of actin-myosin association an...View AnswerShow Answer

Which statement is NOT correct concerning cooperative binding of a ligand to a protein?

Correct AnswerverifiedShow Answer

(a) What is the effect of pH on the binding of oxygen to hemoglobin (the Bohr Effect)? (b) Briefly describe the mechanism of this effect.

Correct AnswerAnswered by ExamLex AI(a) The effect of pH on the binding of o...View AnswerShow Answer

The fundamental cause of sickle-cell disease is a change in the structure of:

Correct AnswerverifiedShow Answer

A test where antibodies are used to quantitatively detect the presence of antiviral antibodies in human blood samples is referred to as:

Correct AnswerverifiedShow Answer

Correct Answer
Answered by ExamLex AI
ATP (adenosine triphosphate) plays a cru...
View Answer

During muscle contraction, the _ of myofibrils contract and the _ move closer together due to the movement of myosin thick filaments along actin thin filaments.

Correct Answer
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The two principal models for the coopera...
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For the binding of a ligand to a protein, what is the relationship between the K_a (association constant), the K_d (dissociation constant), and the affinity of the protein for the ligand?

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The relationship between the association...
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The relative affinity of heme for oxygen...
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Explain why most multicellular organisms use an iron-containing protein for oxygen binding rather than free Fe²⁺. Your answer should include an explanation of (a) the role of heme and (b) the role of the protein itself.

Correct Answer
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Most multicellular organisms use an iron...
View Answer

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Correct Answer
Answered by ExamLex AI
The cycle of actin-myosin association an...
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(a) The effect of pH on the binding of o...
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Correct Answer
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