Chapter 4 quiz

Question 1

The name given to a fully activated and differentiated B cell that secretes antibody is __________________.

a. T cell
b. antigen-presenting cell
c. hematopoietic cell
d. secretory cell
e. plasma cell

Answer 1

e. plasma cell

Question 2

The five isotypes of immunoglobulin differ from each other in their _____.

a. a. light-chain constant regions
b. heavy-chain constant regions
c. light-chain variable regions
d. heavy-chain variable regions
e. heavy-chain variable and constant regions.

Answer 2

b. heavy-chain constant regions

Question 3

The immunoglobulin heavy-chain gene consists of _______ segments, whereas the immunoglobulin light-chain gene consists of _______ segments.

a. κ;λ
b. VDJ; VJ
c. VJ; VDJ
d. P; N
e. RAG-1; RAG-2.

Answer 3

b. VDJ; VJ

Question 4

Which of the following describes two recombination signal sequences required for a permitted somatic recombination event?

a. VH 7-12-9::9-23-7 JH
b. Vλ7-23-9::9-23-7 Jλ
c. DH 7-12-9::9-23-7 JH
d. Vκ7-12-9::7-23-9 Jκ
e. VH 9-23-7::7-12-9 DH

Answer 4

c. DH 7-12-9::9-23-7 JH

Question 5

Which of the following corresponds to the antigen-binding site of immunoglobulins?

a. VH:CH
b. VH:VL
c. VL:CL
d. CH:CL
e. VH:CL

Answer 5

b. VH:VL

Question 6

Another term commonly used to describe hypervariable loops is ___________.

a. multivalency
b. framework regions
c. hinge region
d. complementarity-determining regions (CDR)
e. signal joint

Answer 6

d. complementarity-determining regions (CDR)

Question 7

All of the following are utilized in the binding of antibodies to antigens except:

a. interchain disulfide bonds
b. hydrogen bonding
c. hydrophobic interactions
d. electrostatic forces (salt bridges)
e. van der Waals interactions

Answer 7

a. interchain disulfide bonds

Question 8

With the exception of B cells, all other cells of the body have the immunoglobulin genes in the ______________.

a. germline configuration
b. monoclonal form
c. recombined configuration
d. expressed configuration
e. chimeric form

Answer 8

a. germline configuration

Question 9

Indicate which of the following statements is false.

a. Light chains contain V and J segments, whereas heavy chains contain V, D, and J segments.
b. The Vκ gene segments are duplicated in about 50% of the human population.
c. All immunoglobulin loci include a leader sequence.
d. On the heavy-chain locus, V rearranges to D first, and then J joins the combined VD sequence.
e. Immunoglobulin heavy-chain loci undergo two rounds of somatic recombination, whereas light-chain loci undergo only one.

Answer 9

d. On the heavy-chain locus, V rearranges to D first, and then J joins the combined VD sequence.

Question 10

Which of the following enzymes facilitates the process of affinity maturation?

a. DNA ligase
b. V(D)J recombinase
c. terminal deoxynucleotidyl transferase
d. activation-induced cytidine deaminase (AID)
e. exonuclease

Answer 10

d. activation-induced cytidine deaminase (AID)

Question 11

The process of gene rearrangement in immunoglobulin and T-cell receptor genes is called _________________.

a. somatic hypermutation
b. isotype switching
c. somatic recombination
d. apoptosis
e. clonal selection.

Answer 11

c. somatic recombination

Question 12

Junctional diversity during gene rearrangement results from the addition of __________________.

a. switch region nucleotides
b. P and N nucleotides
c. V, D, and J nucleotides
d. recombination signal sequences
e. mutations in complementarity-determining regions

Answer 12

b. P and N nucleotides

Question 13

A circulating B cell that has never before encountered antigen expresses _____ on the cell surface.

a. IgM and IgD
b. IgM
c. IgD
d. IgM and IgG
e. IgG

Answer 13

a. IgM and IgD

Question 14

All of the following processes occur in mature B cells after antigen encounter except:

a. alternative splicing
b. affinity maturation
c. proliferation
d. somatic recombination
e. isotype switching

Answer 14

d. somatic recombination

Question 15

Which of the following does not describe B-cell receptors?

a. B-cell receptors are membrane-bound and secreted.
b. B-cell receptors consist of a variable region and a constant region.
c. B-cell receptors lack specificity and can bind to a number of different antigens.
d. B-cell receptors possess specificity and can therefore bind only to unique epitopes.
e. B cell receptors undergo affinity maturation as a consequence of somatic hypermutation.

Answer 15

c. B-cell receptors lack specificity and can bind to a number of different antigens.

Question 16

Which of the following determines the isotype of an immunoglobulin?

a. the composition of the hypervariable regions
b. whether the immunoglobulin is membrane-bound or secreted
c. its light chain
d. its heavy chain
e. the composition of the cytoplasmic tails of Igα and Igβ

Answer 16

d. its heavy chain

Question 17

The highest degree of diversity resulting from somatic recombination is concentrated ____________ of the VH and VL domains, whereas the point mutations caused by somatic hypermutation are found ____________.

a. in CDR3; throughout the V region
b. in CDR3; in CDR1 and CDR2 of VH and VL domains
c. in CDR1 and CDR2; in CDR3
d. in CDR1 and CDR2; throughout the V region
e. in all three CDRs; in C regions

Answer 17

a. in CDR3; throughout the V region

Question 18

As an adaptive immune response progresses, the production of variant antibodies that compete more effectively for antigen occurs, and B cells producing these antibodies are preferentially selected on the basis of their improved binding to antigen. This phenomenon is referred to as _______.

a. isotype switching
b. neutralization
c. allelic exclusion
d. affinity maturation
e. somatic rearrangement

Answer 18

d. affinity maturation

Question 19

Which of the following statements about the production and use of monoclonal antibodies is incorrect?

a. Production of monoclonal antibodies requires a purified form of antigen.
b. A monoclonal antibody has specificity for only one epitope of an antigen.
c. B cells are fused with a tumor cell called a myeloma, to immortalize the resulting hybridoma.
d. Monoclonal antibodies made in mice have limited therapeutic potential.
e. Humanized monoclonal antibodies reduce complications associated with using mouse monoclonal
antibodies.

Answer 19

a. Production of monoclonal antibodies requires a purified form of antigen.

Question 20

The mutational mechanism that results in the production of antibodies that bind antigen with higher affinity is called _____.

a. somatic recombination
b. isotype switching
c. somatic hypermutation
d. clonal selection
e. antigen processing

Answer 20

c. somatic hypermutation

Question 21

The process of _____ results in change in the constant region of the heavy-chain of antibodies, causing a change in the effector function and transport properties of antibodies.

a. complement fixation
b. neutralization
c. isotype switching
d. somatic hypermutation
e. somatic recombination

Answer 21

c. isotype switching

Question 22

The process used to produce either surface or secreted forms of the immunoglobulin heavy chain is called __________________.

a. alternative RNA processing
b. isotype switching
c. somatic recombination
d. somatic hypermutation
e. opsonization

Answer 22

a. alternative RNA processing

Question 23

Which immunoglobulin is transported most efficiently across mucosal epithelium?

a. IgA
b. IgD
c. IgE
d. IgG
e. IgM

Answer 23

a. IgA

Question 24

A newborn derives passive immunity from its mother as a result of placental transfer of _____ during pregnancy.

a. IgA
b. IgD
c. IgE
d. IgG
e. IgM

Answer 24

d. IgG

Question 25

The process of _____ results in the amplification of particular B cells with specificity for antigen.

a. germline recombination
b. somatic recombination
c. clonal selection
d. antigen processing
e. antigen presentation

Answer 25

c. clonal selection