This set of Immunology Multiple Choice Questions & Answers (MCQs) focuses on “Immunoglobulin Gene Structure and their Multigene Organization”.
1. What are the chains of an immunoglobulin comprises of?
a) One heavy chain and one light chain
b) Two heavy chains and two light chains
c) One heavy chain and two light chains
d) Two heavy chains and one light chain
View Answer
Explanation: An immunoglobulin comprises four chains made up of polypeptides. They are two heavy chains and two light chains. They in turn contain regions which are variable and also constant and conserved.
2. The heavy chains and light chains in an immunoglobulin are held together by ________ bonds.
a) Covalent
b) Disulphide
c) Hydrogen
d) Ionic
View Answer
Explanation: A heavy chain and a light chain and also a heavy chain and a heavy chain in an immunoglobulin are held together by disulphide bonds, hence them being very strong.
3. When does the organization of the genes in an immunoglobulin take place?
a) During the development and differentiation of T cells
b) During the development and differentiation of B cells
c) During the development and differentiation of both B cells and T cells
d) During the development and differentiation of neither B cells nor T cells
View Answer
Explanation: The organization and the rearrangements of genes in an immunoglobulin take place during the development and differentiation of B cells.
4. What are the multigene families that are present in a heavy chain or a light chain of an immunoglobulin called?
a) Gene segments
b) Gene coders
c) Gene clusters
d) Gene fragments
View Answer
Explanation: The various multigene families that are present in an immunoglobulin are called the gene segments. These gene segments don’t have a number in particular.
5. The gene segments in an immunoglobulin are separated by non-coding genes.
a) True
b) False
View Answer
Explanation: Immunoglobulins are composed of multigene families called the gene segments. These gene segments are separated by non-coding genes.
6. The variable region of a light chain in an immunoglobulin is encoded by the _________
a) Segment V
b) Segment J
c) Segment C
d) Segments VJ
View Answer
Explanation: A light chain has three main gene segments, The V(variable) segment, the J(joining) segment and the C(constant) segment. The variable region is encoded by both V and J segments.
7. The light chain development of an immunoglobulin takes place at the time of _______ processing.
a) DNA
b) mRNA
c) tRNA
d) rRNA
View Answer
Explanation: The organization and development of a light chain in an immunoglobulin takes place at the time of mRNA processing. It can be either a kappa or a lambda.
8. What are the types of light chain that are developed in an immunoglobulin?
a) Either a kappa or a lambda
b) Either a kappa or a gamma
c) Either a gamma or a lambda
d) Either a gamma or a delta
View Answer
Explanation: There are two types of lights chains, they are kappa chain and lambda chain. The decision of which type of chain it is to be made during mRNA processing.
9. A functional variable region gene of a light chain contains two coding gene segments that are separated by a non-coding DNA sequence in germ-line DNA.
a) True
b) False
View Answer
Explanation: A functional variable region gene of a light chain contains two coding gene segments that are separated by a non-coding DNA sequence in germ-line DNA. This variable region is still unrearranged.
10. Heavy chain of an immunoglobulin also has three gene segments.
a) Yes
b) No
View Answer
Explanation: The heavy chain of an immunoglobulin has four gene segments. There is an extra segment present between V and J segments called D(diversity) segment.
11. Where does the variable region rearrangements of an immunoglobulin take place?
a) Thymus
b) Bone marrow
c) Spleen
d) Lymphatic tissue
View Answer
Explanation: During the process of B cell maturation, the variable region rearrangements of an immunoglobulin take place. The whole process is carried out in bone marrow.
12. What happens to the diversity of antibodies/immunoglobulins with the insertion of D segment in heavy chain?
a) Increases
b) Decreases
c) Remains constant
d) Diversity is independent of D segment
View Answer
Explanation: The D segment that is present in the heavy chains of immunoglobulins is also a coding gene. With its insertion, the diversity in antibodies increases.
13. What is the other type of region that is present in the constant gene region of the heavy chain of an immunoglobulin?
a) Framework region
b) CDR region
c) Hinge region
d) Bent region
View Answer
Explanation: Hinge region is present between the first and second constant regions of a heavy chain. It provides flexibility to the immunoglobulin.
14. What are the regions that are responsible for diversity in an immunoglobulin called?
a) Framework region
b) CDR region
c) Hinge region
d) Bent region
View Answer
Explanation: CDR (complementarity-determining region) are responsible for the diversity in immunoglobulins. They are present in the variable region.
15. What is the region that is present between the CDRs in the variable region of a heavy chain in an immunoglobulin called?
a) Framework region
b) CDR region
c) Hinge region
d) Bent region
View Answer
Explanation: The region that is present in between the CDRs is called the Framework region. framework region provides structural support to an immunoglobulin. It acts as a scaffold.
Sanfoundry Global Education & Learning Series – Immunology.
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