Biology Exam Questions for NEET Exam on “Human Health and Disease – Humoral Immunity-2”.
1. Which region of an antibody is also called a ‘Fragment of Crystallization’?
a) Fc region
b) Fab region
c) CC region
d) NN region
Answer: a
Clarification: Fc region of an antibody is also called as a Fragment of Crystallization. It is responsible for the effector function. It is also called a constant region. It determines the isotype of an immunoglobulin.
2. What is the approximate weight of Heavy and Light chains respectively?
a) 50,000 Da and 25,000 Da
b) 25,000 Da and 50,000 Da
c) 75,000 Da and 25,000 Da
d) 75,000 Da and 50,000 Da
Answer: a
Clarification: Each antibody molecule has four peptide chains, two long chains called heavy or H chain each of molecular weight 50,000 Da and two short chains called light or L chains each of approximate molecular weight 25,000 Da.
3. Which region of an antibody is also called as ‘Variable Region’?
a) Fc region
b) Fab region
c) NN region
d) CC region
Answer: b
Clarification: Fab region of an antibody is also called a variable region. The Fab portion is so called because it is the fragment of the molecule which is antigen binding or a paratope.
4. Antigens are generally Antibody generating molecules.
a) True
b) False
Answer: a
Clarification: The word ‘Antigen’ has been derived from ‘Antibody Generating’ because they stimulate the production of antibodies in response to an infection.
5. Which of the following antibodies constitute the largest proportion of the total antibodies present?
a) IgA
b) IgM
c) IgG
d) IgE
Answer: c
Clarification: IgG antibodies constitute 75% of the total antibodies present in the blood. It is present in the monomer form and has two paratopes. It also evokes the complementary system and Opsonisation.
6. Which of the following is the smallest antibody?
a) IgG
b) IgA
c) IgD
d) IgE
Answer: a
Clarification: IgG is the smallest of all the antibodies. Also, it is the only antibody that can cross the placenta and confer immunity to the foetus. It only has two paratopes.
7. Which of the following is correctly matched in the following figure?
a) Antigen binding site
b) Disulphide bonds
c) Heavy chain
d) Light chain
Answer: a
Clarification: Antigen binding site is correctly matched in the following figure. The correct labelling of the following figure is: