Chapter 5: Generation of Antibody Diversity

This activity contains 20 questions.

	In the light of clonal selection theory, which of the following statements is false?   The specificity of an antibody molecule is determined prior to its encounter with antigen One B cell produces antibody molecules of a single specificity An antigen entering the host body simply “selects” and “switches on” a specific B cell Upon second encounter of the antigen, B cells can change their specificity

	The human heavy-chain and λ light-chain genes are located on _______ and ________ chromosomes, respectively.   12, 22 12, 2 14, 22 14, 2

	Which of the gene segments do not contribute to the light chain of antibody molecules?   V J C D

	The primary RNA transcript of the κ chain contains rearranged:   V–D–J gene segments V–D gene segments V–J gene segments V–J–C gene segments

	Which of the following statements is false for recombination signal sequences?   Presence of two conserved sequences—heptamer and spacer RSS is located on 3′ side of the V gene RSS are present on both sides of the D segment. RSS is located on 5′ side of the J gene

	CDR3 of the heavy chain of an antibody is coded by:   D–J gene segments V–D–J gene segments V–J gene segments V–D gene segments

	One enzyme that is not involved in V(D)J rearrangement in an antibody molecules:   RAG-2 AID TdT RAG-1

	The process through which primary transcripts can be spliced to generate membrane-bound and secreted forms of a heavy-chain polypeptide is called:   Alternative splicing Combinatorial association Somatic hypermutation Allelic exclusion

	During generation of diversity in the antibodies ,which of the following enzymes does not require a template for the addition of nucleotides:   Terminal deoxynucleotidyl transferase(TdT) Activation-induced cytosine deaminase(AID) DNA polymerase DNA Ligase

	Isotype switching cannot occur from IgG to:   IgA All of the above IgM IgE

	Switch region is 2 kbp sequence located upstream of each CH segment except:   Cμ Cδ Cα Cε

	After somatic hypermutation, the one characteristic of an antibody that changes is:   Affinity Molecular weight Solubility Specificity

	Which one of the following cell will not have α1 gene segment(that codes for IgA1) in their germ-line DNA?   Stem cell Immature B cell IgE-secreting plasma cell IgM-secreting plasma cell

	In mammals, which of the following does not contribute to the generation of antibody diversity?   Combinational diversity Gene conversion Junctional diversity Multiple germ-line gene segments

	Junctional diversity could be generated by all of the following except:   N-additions Imprecise joining of V, (D), J segments P-additions Somatic hypermutation

	The enzyme that is involved in increasing the affinity of an antibody is:   TdT RAG-1 AID RAG-2

	Pollen grains inhaled by a child cause a severe asthmatic attack. This reaction could be because of:   IgA IgG IgD IgE

	Class switching of antibodies involves:   Change of λ chain to κ chain Change of κ chain to λ chain Change of one CH gene segment to a different CH gene segment Change of one complete heavy-chain polypeptide to another

	Which of the statements is not correct?   J chain-deficient individuals will have a vulnerable mucosal surface A cell can synthesize IgG2 and then switch to IgG4 antibodies IgG can cross the placenta Immunoglobulin genes are un-rearranged in adipocytes

	A B cell expresses antibodies of more than one specificity. Which of the following events do you think did not occur?   Combinatorial pairing Somatic hypermutation V–D–J recombination Allelic exclusion

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