Read the following passage carefully and answer the given questions.
The B-lymphocytes produce an army of proteins in response to pathogens. Each antibody molecule has four peptide chains, two small called light chains and two longer called heavy chains. Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection. Symptoms of allergic reactions include sneezing, watery eyes, running nose and difficulty in breathing. The use of drugs like anti-histamine, adrenalin and steroids quickly reduce the symptoms of allergy. Lymphoid organs are the organs where origin and/or maturation and proliferation of lymphocytes occur. The primary lymphoid organs are bone marrow and thymus. After maturation the lymphocytes migrate to secondary lymphoid organs like spleen, lymph nodes, tonsils, Peyer’s patches of small intestine and appendix. Heroin commonly called smack is chemically diacetylmorphine which is a white, odourless, bitter crystalline compound. This is obtained by acetylation of morphine, which is extracted from the latex of poppy plant Papaver somniferum.
Which one of the following is not a feature of an antibody:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → T-lymphocytes produce antibodies in response to pathogens in our blood to fight with them
The passage says that B-lymphocytes produce an army of proteins in response to pathogens, and that each antibody molecule has four peptide chains: two small light chains and two longer heavy chains. So an antibody is written as H2L2. Antibodies give the humoral immune response, because they are found in the blood.
Option (1) Each antibody has 4 peptide chains — A feature of an antibody. Two light and two heavy chains make four in all.
Option (2) Two small peptide chain in antibody structure are called light chains — A feature of an antibody. The two shorter chains are the light (L) chains.
Option (3) Two longer peptide chains in the antibody structure are called heavy chains — A feature of an antibody. The two longer chains are the heavy (H) chains.
Option (4) T-lymphocytes produce antibodies in response to pathogens in our blood to fight with them — Not a feature of an antibody. Antibodies are made by B-lymphocytes, not T-lymphocytes. T-cells do not make antibodies; they help the B-cells and give the cell-mediated immune response, as in graft rejection.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.