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Another term commonly used to describe hypervariable loops is


A) multivalency
B) framework regions
C) hinge region
D) complementarity-determining regions
E) signal joint.

F) A) and D)
G) A) and E)

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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.

F) B) and E)
G) B) and C)

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D

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.

F) A) and E)
G) A) and C)

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In what way does the κ light chain differ from the λ light chain?


A) κ performs a different function from λ when bound to the immunoglobulin heavy chain.
B) κ,but not λ,is encoded on the same chromosome as the heavy-chain locus.
C) κ contains a VJ region,whereas λ contains a VDJ region.
D) The κ locus encodes a single C segment,whereas the λ locus has more than one.
E) κ contains a transmembrane domain but lambda does not.

F) A) and E)
G) B) and E)

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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.

F) A) and B)
G) C) and D)

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A. What is an epitope? B. Define the term multivalent antigen. C. How does a linear epitope differ from a conformational epitope? D. Do antibodies bind their antigens via noncovalent bonding or via covalent bonding?

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A.An epitope is the specific part of the...

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A. Explain briefly how a vast number of immunoglobulins of different antigen specificities can be produced from the relatively small number of immunoglobulin genes present in the genome. Include the following terms in your explanation: somatic recombination; germline configuration; V, D, and J segments. B. What is the final arrangement of gene segments in the rearranged immunoglobulin heavy-chain gene V region, and in what order do these gene segment rearrangements occur? C. In what order do the various immunoglobulin loci rearrange?

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A. In developing B cells, gene rearrangements within the genetic loci for immunoglobulin light and heavy chains can produce an almost unlimited variety of different variable regions, and thus produce the huge repertoire of antibodies with different specificities for many types of antigen. This gene rearrangement mechanism is called somatic recombination. In the germline configuration, before gene rearrangement, the immunoglobulin loci in progenitor B cells are composed of sequences encoding the constant regions and families of gene segments encoding different portions of the variable region. Heavy-chain loci contain a series of gene segments called variable (V), diversity (D), and joining (J). Light-chain loci contain only V and J gene segments. In somatic recombination in developing B cells, one of each family of gene segments is randomly selected and joined together to give a complete variable-region sequence, which is subsequently expressed as an immunoglobulin heavy or light chain. Immunoglobulin gene rearrangement is irreversible, leading to permanent alteration of the chromosome; it occurs exclusively in B cells. B. A D gene segment first joins to a J to form DJ, followed by a V becoming joined to DJ to form VDJ, which encodes a complete variable region. C. The heavy-chain locus rearranges before the light-chain loci. For light chains in humans, the κ locus rearranges first and is followed by the λ locus only if both κ loci fail to produce a successful rearrangement.

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.

F) A) and E)
G) A) and C)

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Which of the following statements is correct concerning membrane-coding (MC) exons of immunoglobulin genes?


A) MC exons are located upstream (5′) of the constant-domain exons.
B) MC exons code for amino acids that anchor and stabilize the light chain to the membrane of B cells.
C) MC exons specify transmembrane hydrophobic amino acids that associate with the B-cell membrane.
D) MC exons are removed from primary RNA transcripts as a consequence of alternative mRNA splicing when secreted antibodies are produced by plasma cells.
E) Somatic hypermutation causes alteration in the coding sequence of MC exons.

F) B) and D)
G) D) and E)

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The enzyme responsible for adding N nucleotides is


A) V(D) J recombinase
B) terminal deoxynucleotidyl transferase
C) uracil-DNA-glycosylase (UNG)
D) DNA ligase
E) activation-induced cytidine deaminase (AID) .

F) B) and C)
G) A) and B)

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B

How is additional diversity introduced into the variable region by the molecular mechanism of somatic recombination? Include the following terms in your

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The rejoining and repair of DNA during t...

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Explain how mature,naive B cells co-express IgM and IgD.

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Naive B cells express IgM and IgD simult...

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_____ is secreted into the bloodstream,whereas _____ is secreted into mucus such as gastrointestinal fluid,colostrum,saliva,tears,and sweat.


A) monomeric IgM: pentameric IgM
B) monomeric IgA: dimeric IgA
C) monomeric IgA: dimeric IgG
D) monomeric IgA: monomeric IgM
E) dimeric IgA: pentameric IgM.

F) D) and E)
G) A) and B)

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


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.

F) A) and C)
G) None of the above

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In contrast with leader peptides and the C regions,the V regions in immunoglobulin heavy-chain genes


A) encode hydrophobic amino acids that anchor the immunoglobulin chains to B-cell membranes
B) comprise the smallest number of gene segments in the human immunoglobulin loci
C) are composed of V,D,and J gene segments that must undergo gene rearrangement to generate a transcribable exon
D) do not undergo somatic hypermutation
E) are not subject to allelic exclusion.

F) None of the above
G) B) and C)

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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

F) B) and C)
G) C) and D)

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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.

F) A) and D)
G) B) and D)

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On the heavy-chain immunoglobulin gene locus,recombination signal sequences flank _______ of the V segment,_______ of the D segment,and _______ of the J segment.


A) the 5′ side; both sides; the 3′ side
B) the 5′ side; the 5′ side,the 5′ side
C) the 3′ side; both sides; the 3′ side
D) both sides; both sides; both sides
E) the 3′ side; both sides; the 5′ side.

F) A) and B)
G) A) and C)

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The _______ contribute to antigen specificity of immunoglobulins,and _______ make up the more conservative flanking regions.


A) hypervariable loops; framework regions
B) constant domains; variable domains
C) heavy chains; light chains
D) variable gene segments; joining gene segments
E) antigenic determinants; complementarity determining regions.

F) A) and E)
G) A) and D)

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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.

F) A) and E)
G) A) and C)

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