Immunogenetics Questions: Test! Quiz

13 Questions | Total Attempts: 458

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Immunogenetics Questions: Test! Quiz

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Questions and Answers
  • 1. 
    The greater hypervariability of the CDR3 region compared to the CDR1 region of immunoglobulin heavy chains can be partly attributed to the enzyme terminal deoxyribonucleotide transferase because of its role in:
    • A. 

      Precise nucleotide splicing during gene rearrangement

    • B. 

      Somatic hypermutation

    • C. 

      Switch recombination.

    • D. 

      Combinatorial diversity

    • E. 

      Non template nucleotide additions

  • 2. 
    When a B-cell undergoes immunoglobulin class switching:
    • A. 

      The variable region of the light chain changes, but its constant region remains the same

    • B. 

      The variable region of the light chain remains the same, but its constant region changes.

    • C. 

      The variable region of the heavy chain remains the same but its constant region changes

    • D. 

      The variable region of the heavy chain changes but its constant region remains the same

    • E. 

      Both the variable and constant regions change

  • 3. 
    As predicted by the clonal selection hypothesis, B cells express cell-surface IgM of the same specificity as the IgM produced for secretion. This is possible because of:
    • A. 

      Switch recombination

    • B. 

      Productive V(D)J recombination on both alleles

    • C. 

      Selective pressure

    • D. 

      Alternative polyA site usage

    • E. 

      Post-translational modifications of the primary protein product

  • 4. 
    Which of the following does not contribute to the generation of diversity of B-cell antigen receptors?
    • A. 

      Multiple V genes in the germ line

    • B. 

      Random assortment of L and H chains

    • C. 

      Imprecise recombination of V and J or V, D, and J segments

    • D. 

      Inheritance of multiple C-region genes

    • E. 

      Somatic mutation

  • 5. 
    After binding to its specific antigen, a B lymphocyte may switch its:
    • A. 

      Immunoglobulin light-chain isotype

    • B. 

      Immunoglobulin heavy-chain class

    • C. 

      The variable region of the immunoglobulin heavy chain

    • D. 

      The constant region of the immunoglobulin light chain

  • 6. 
    “Isotype switching” of immunoglobulin classes by B cells involves:
    • A. 

      Simultaneous insertion of VH genes adjacent to each CH gene

    • B. 

      Successive insertion of a single VH gene adjacent to different CH genes

    • C. 

      Activation of homologous genes on chromosome 6

    • D. 

      Switching of light-chain types (kappa and lambda)

  • 7. 
    During the maturation of a B lymphocyte, the first immunoglobulin heavy chain synthesized is the:
    • A. 

      Mu chain

    • B. 

      Gamma chain

    • C. 

      Epsilon chain

    • D. 

      Alpha chain

  • 8. 
    The antibody-binding site is formed primarily by:
    • A. 

      The constant regions of H and L chains

    • B. 

      The hypervariable regions of H and L chains

    • C. 

      The hypervariable regions of H chains

    • D. 

      The variable region of H chains

    • E. 

      The variable region of L chains

  • 9. 
    An individual who is heterozygous for Gm allotypes contains two allelic forms of IgG in serum, but individual lymphocytes produce only one of the two forms.  This phenomenon, known as “allelic exclusion,” is consistent with
    • A. 

      A rearrangement of a heavy-chain gene on only one chromosome in a lymphocyte

    • B. 

      Rearrangements of heavy-chain genes on both chromosomes in a lymphocyte

    • C. 

      A rearrangement of a light-chain gene on only one chromosome in a lymphocyte

    • D. 

      Rearrangements of light-chain genes on both chromosomes in a lymphocyte

  • 10. 
    The hypervariable region of an antibody light chain results from: (concept – how antibody hypervariable regions are generated)
    • A. 

      Alternative splicing of the corresponding pre-RNA during maturation.

    • B. 

      Clipping the amino-terminal end of the polypeptide during secretion

    • C. 

      Presence of multiple J segments within the corresponding gene.

    • D. 

      Presence of multiple LV segments within the corresponding gene

    • E. 

      Addition of nucleotides between LV and J segments in maturing lymphocytes

  • 11. 
    Cells express cell-surface IgM of the same specificity as the IgM produced for secretion. This is possible because of:       (concept – how soluble IgM is generated)
    • A. 

      Switch recombination

    • B. 

      Productive V(D)J recombination on both alleles

    • C. 

      Selective pressure

    • D. 

      Alternative splicing of a primary RNA transcript.

    • E. 

      Post-translational modifications of the primary protein product

  • 12. 
    An IgG2 molecule is composed of which of the following?
    • A. 

      One alpha, one gamma2, and two kappa chains

    • B. 

      One gamma1 chain and two kappa chains

    • C. 

      Two gamma1 chains and one kappa and one lambda chain

    • D. 

      Two gamma1 chains and two kappa chains

    • E. 

      Two gamma2 chains and two kappa chains

  • 13. 
    The earliest stages of B-cell differentiation:
    • A. 

      Occur in the embryonic thymus

    • B. 

      Require the presence of antigen

    • C. 

      Involve rearrangement of -chain gene segments

    • D. 

      Involve the rearrangement of surrogate light-chain gene segments

    • E. 

      Involve a rearrangement of heavy-chain gene segments

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