Concept explainers
The primary B-cell receptor is
- a. IgD.
- b. IgA.
- c. IgE.
- d. IgG.
Introduction:
Immunoglobulins are the glycoprotein molecules which are present in a Y shaped structure. They bind to the antigenic foreign epitopes and inhibit the spread of infection inside the human body. They are composed of one heavy chain and one light chain with variable and constant regions in the polypeptide protein.
Answer to Problem 1MCQ
Correct answer:
The primary B-cell receptor is IgD. Therefore, option (a) is correct.
Option (a) is given as “IgD”.
Explanation of Solution
Justify reason for the correct statement:
In the case of B lymphocytes, the genes code for Ig (immunoglobulins) synthesis, which are the receptors for B-cells. There are antigen binding sites in the ends of forks that are formed by the heavy and light chains and are variable in shape with respect to the shape of antigens. IgDis one of the classes of Igs that is secreted in blood and is present as a part of the membrane surface receptor molecule on
Hence, option (a) is correct.
Justify reasons for the incorrect statements:
Option (b) is given as “IgA”.
IgA is secreted in the lactating milk and forms the defense immunity in a child. It is not the primary Ig of B-cell receptors. Hence, it is a wrong answer.
Option (c) is given as “IgE”.
IgE is released from the mast cells following an antigenic response in the human body. It is not the primary Ig of B-cell receptors. Hence, it is a wrong answer.
Option (d) is given as “IgG”.
IgG is the antibody which is formed from activated
Hence, options (b),(c), and(d) are incorrect.
IgD is the immunoglobulin class that is considered as the primaryreceptor of B-cell.
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Chapter 15 Solutions
Microbiology: A Systems Approach
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