Antibody Structure and Function

Question 1

Which is characteristic of variable domains of immunoglobulins?

a. They occur on both the H and L chains.
b. They represent the complement binding site.
c. They are at the carboxy-terminal ends of the molecules.
d. All of the above

Answer 1

a. They occur on both the H and L chains.

Question 2

All of the following are true of IgM except that it

a. can cross the placenta.
b. fixes complement.
c. has a J chain.
d. is a primary response antibody.

Answer 2

a. can cross the placenta.

Question 3

3. How many antigen binding sites does a typical IgM molecule have?

a. 2
b. 4
c. 6
d. 10

Answer 3

b. 4

Question 4

Bence-Jones proteins are identical to which of the
following?
a. H chains
b. L chains
c. IgM molecules
d. IgG molecules

Answer 4

b. L chains

Question 5

A Fab fragment consists of

a. two H chains.
b. two L chains.
c. one L chain and one-half of an H chain.
d. one L chain and an entire H chain.

Answer 5

c. one L chain and one-half of an H chain.

Question 6

Which of the following pairs represents two different immunoglobulin allotypes?

a. IgM and IgG
b. IgM1 and IgM2
c. Antihuman IgM and antihuman IgG
d. IgG1m3 and IgG1m17

Answer 6

d. IgG1m3 and IgG1m17

Question 7

Which of the following are L chains of antibody molecules?

a. kappa
b. gamma
c. mu
d. alpha

Answer 7

a. kappa

Question 8

If the results of serum protein electrophoresis show a significant decrease in the gamma band, which of the
following is a likely possibility?

a. Normal response to active infection
b. Muliple myeloma
c. Immunodeficiency disorder
d. Monoclonal gammopathy

Answer 8

c. Immunodeficiency disorder

Question 9

The subclasses of IgG differ mainly in

a. the type of L chain.
b. the arrangement of disulfide bonds.
c. the ability to act as opsonins.
d. molecular weight

Answer 9

b. the arrangement of disulfide bonds.

Question 10

Which best describes the role of the SC of IgA?

a. A transport mechanism across endothelial cells
b. A means of joining two IgA monomers together
c. An aid to trapping antigen
d. Enhancement of complement fixation by the classical pathway

Answer 10

a. A transport mechanism across endothelial cells

Question 11

11. Which represents the main function of IgD?

a. Protection of the mucous membranes
b. Removal of antigens by complement fixation
c. Enhancing proliferation of B cells
d. Destruction of parasitic worms

Answer 11

c. Enhancing proliferation of B cells

Question 12

Which antibody is best at agglutination and complement
fixation?

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

Answer 12

d. IgM

Question 13

Which of the following can be attributed to the clonal selection theory of antibody formation?

a. Plasma cells make generalized antibody.
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b. B cells are preprogrammed for specific antibody synthesis.
c. Proteins can alter their shape to conform to antigen.
d. Cell receptors break off and become circulating antibody.

Answer 13

b. B cells are preprogrammed for specific antibody synthesis.

Question 14

4. All of the following are true of IgE except that it

a. fails to fix complement.
b. is heat stable.
c. attaches to tissue mast cells.
d. is found in the serum of allergic persons

Answer 14

b. is heat stable.

Question 15

Which best describes coding for immunoglobulin molecules?

a. All genes are located on the same chromosome.
b. L chain rearrangement occurs before H chain rearrangement.
c. Four different regions are involved in coding of H chains.
d. λ rearrangement occurs before κ rearrangement

Answer 15

c. Four different regions are involved in coding of H chains

Question 16

What is the purpose of HAT medium in the preparation of monoclonal antibody?

a. Fusion of the two cell types
b. Restricting the growth of unfused myeloma cells.
c. Restricting the growth of unfused spleen cells
d. Restricting antibody production to the IgM class

Answer 16

b. Restricting the growth of unfused myeloma cells.