Question 1

Choose the correct order of the steps of light chain gene recombination.

Accepted Answer

A)   Gene segments loop close together, signal joint removed, hairpins formed and opened, gene segments ligated together
B)   Hairpins formed and opened, gene segments loop close together, signal joint removed, gene segments ligated together
C)   Signal joint removed, hairpins formed and opened, gene segments loop close together, gene segments ligated together
D)   Gene segments loop close together, gene segments ligated together, hairpins formed and opened, signal joint removed A

Question 2

The hypervariable complementarity-determining regions (CDRs) are primarily coded for by which gene region or regions?
 I- Joining (J)
II- Variable (V)
III- Diversity (D)

Accepted Answer

A)   I only
B)   III only
C)   I and II
D)   II and III
E)   I, II, and III C

Question 3

The addition of N-nucleotides has which effect on antibody structure?

Accepted Answer

A)   Determines if the light chain is a l-chain or k-chain
B)   Allows for removal of amino acids in the open hairpins
C)   Adds the C4 region to the heavy chain of some antibodies
D)   Changes the amino acid sequence in the hypervariable CDR3 D

Question 4

Somatic mutation theory of antibody diversity states that:

Accepted Answer

A)   A limited number of genes undergo mutations
B)   Separate genes exist for each antibody molecule
C)   A limited number of genes undergo genetic rearrangements
D)   The many genes inherited from both parents undergo a few mutations

Question 5

During recombination, which enzymes are responsible for formation of the DNA hairpins?

Accepted Answer

A)   Endonucleases
B)   RAG1 and RAG2
C)   Artemis and DNA-dependent kinase (DNA-PK) 
D)   Multiple terminal deoxynucleotidyl transferases

Question 6

Which of the following represents possible antibody conformations? 
I. One l light chain, one k light chain, two g heavy chains
II. Two l light chains, one g heavy chain, one m heavy chain
III. Two k light chains, two m heavy chains

Accepted Answer

A)   I only
B)   III only
C)   I and II
D)   II and III
E)   I, II, and III

Question 7

Small nuclear RNA and small nuclear riboprotein are involved in which process?

Accepted Answer

A)   Opening of hairpins
B)   Ligation of V and J genes
C)   Addition of P- and N-nucleotides
D)   Attachment of C genes to V and J genes

Question 8

Mutations in which genes in germinal center B cells lead to the production of higher affinity antibodies?

Accepted Answer

A)   V genes
B)   D genes
C)   J genes
D)   C genes

Question 9

What is the purpose of the recognition signal sequences (RSSs) in rearrangement of genes?

Accepted Answer

A)   The RSSs are the coding regions of the DNA.
B)   The RSSs are the enzymes that facilitate recombination.
C)   The RSSs are spacers that align genes on the same side of DNA.
D)   The RSSs are the areas that determine the antigen-binding pocket.

Exam 10: Antibody Diversity