This set of Structural Biology Multiple Choice Questions & Answers (MCQs) focuses on “Immunoglobulin”.
1. How do most protein-ligand interactions occur?
a) Involve a prosthetic group
b) Presence of amino acids lining a cleft in the protein
c) Require an enzyme
d) Without a prosthetic group
View Answer
Explanation: Most protein-ligand interactions occur because of the amino acids lined along a cleft in the protein such that the interaction between the ligand and protein is highly specific.
2. The immune system consists of _______
a) Humoral and cellular immune systems
b) Humoral and cellular regeneration systems
c) Cellular immune and regeneration systems
d) Cellular immune and signalling systems
View Answer
Explanation: The humoral immune system focuses primarily on fighting off bacterial infections and viruses and the cellular immune system works towards destroying host cells infected by viruses.
3. Which of these are responsible for the recognition of infected cells or invading parasites?
a) Cytotoxic T-cells
b) T-cell receptors
c) B lymphocytes
d) Helper T-cells
View Answer
Explanation: T-cell receptors are found on the surface of cytotoxic T-cells. The binding of an antigen to these receptors triggers changes in the cells, signalling the immune system of a threat.
4. The term epitope refers to ________
a) Individual antigen binding to a structure within an antibody
b) Antigen binding to any host cell
c) Individual antibody binding to a specific structure within an antibody
d) Production of antibody
View Answer
Explanation: A complex antigen maybe bound by several different antibodies. But when a singular or individual antibody binds to a very particular part in the antigen, it’s called an antigenic determinant or an epitope.
5. The most abundant type of antibody found in all body fluids is ______
a) IgA
b) IgM
c) IgE
d) IgG
View Answer
Explanation: IgG is the most abundant protein in all body fluids, especially blood serum, which fights bacterial and viral infections.
6. Which of the following is also called the natural antibody?
a) IgA
b) IgM
c) IgE
d) IgG
View Answer
Explanation: It is the first line of defence against foreign bodies, i.e. it is the first antibody to be produced to fight off antigens. It was found that IgM binds to specific antigens, even in cases where the host had not been immunized before, hence the name.
7. The four polypeptide chains found in IgG are bound together by ______
a) Noncovalent and disulphide bonds
b) Covalent and disulphide bonds
c) Disulphide and hydrogen bonds
d) Noncovalent and hydrogen bonds
View Answer
Explanation: IgG is a large molecule with two large polypeptide chains called heavy chains and two light chains. These are linked to form a complex by disulphide bonds.
8. How are the different classes of immunoglobulins different from each other?
a) Variability in amino acid sequence of variable domain
b) Variability in amino acid sequence of constant domain
c) Variability in amino acid sequence of hypervariable domain
d) Variability in amino acid sequence of all the three domains
View Answer
Explanation: There are three constant domains in each of the four polypeptide chains of immunoglobulins, and the differences in the amino acid sequences of the constant regions of the heavy, polypeptide chain of the antibody.
9. An immunoglobulin is essentially a glycolipid.
a) True
b) False
View Answer
Explanation: Immunoglobulins are glycoproteins, composed of multiple subunits which are in turn made up of four polypeptide chains each (sugar chains). Their terminal amino acid sequences are different for each immunoglobulin, and this variance is called the variable region.
10. Antibodies or Immunoglobulins occur in two physical forms, namely _______
a) Soluble and membrane-bound forms
b) Insoluble and trans-membrane forms
c) Soluble and trans-membrane forms
d) Insoluble and membrane-bound forms
View Answer
Explanation: Antibodies are produced by B cells or B lymphocytes in soluble form, that is found in blood plasma and the membrane-bound form which is often found attached to a B cell. The latter is also referred to as the B cell receptor.
Sanfoundry Global Education & Learning Series – Structural Biology.
To practice all areas of Structural Biology, here is complete set of Multiple Choice Questions and Answers.
If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]
