NIOS Class 12 Biology Chapter 31 Solution – Immunobiology: An Introduction
NIOS Class 12 Biology Solution Chapter 31 Immunobiology: An Introduction . NIOS Class 12 Biology Chapter 31 Question Answers Download PDF. NIOS Class 12 Biology Notes.
Board |
NIOS |
Class |
12th (Higher Secondary) |
Subject |
Biology |
Topic |
Question Answer, Solution, Notes |
INTEXT 31.1
1.) Who is considered as the father of immunobiology?
Ans: Edward Jenner (1749-1823) is considered to be the father of modern immunobiology. He demonstrated that inoculation of cowpox crusts afforded protection to humans against smallpox
2.) What are the three main functions of immunological defence?
(i) Defence against microorganisms. (ii) Homeostasis i.e. removal of damaged (non functional) cells to maintain normal state. (iii) Surveillance i.e. recognition and destruction of mutant cells
3.) Define immunology.
Ans: The study of immune system structure and operation is known as immunobiology. Immunity—the ability to be protected against diseases—is provided by the immune system.
INTEXT 31.2
1.) Name the two categories of immune cells.
Ans: (i) Central or primary lymphoid organs. (ii) Peripheral or secondary lymphoid organs are the categories of immune cells
2.) Name the organ found in birds where B-cells are produced.
Ans: The organ found in birds where B cells are produced is Bursa of Fabricius.
3.) Write the two main functions of B-cells.
Ans: Main functions of B-cells
1.) Initiate antibody-mediated immune response.
2.) Transform into plasma cells which secrete antibodies
4.) Name the cells responsible for synthesis of antibodies.
Ans: Plasma cells/B-cells is responsible for synthesis of antibodies.
5.) What is the function of T-helper cells?
Ans: The main function of T helper cells are
(i) Regulate immune response.
(ii) Mediate cell-mediated immune (CMI) response.
(iii) Induce B-cells to produce antibody
INTEXT 31.3
1.) Name the part of antigen which makes contact with antibody.
Ans: Epitope
2.) How many types of immunoglobulins are known? (Give only the number).
Ans: There are tptal Five immunoglobulins
3.) Name the immunoglobulin found in highest concentration.
Ans: Immunoglobulin G are found in highest concentration
4.) Which type of immune response is responsible for the killing of cancer cells?
Ans: Cell-mediated immune response is responsible for the killing of cancer cells. It kill the intracellular organisms.
INTEXT 31.4
1.) Mention two physical barriers of the body.
Ans: Skin The outer tough layer of skin is formed of keratin and is almost impermeable to germs. Body secretions such as sweat and secretion from eyes also ward off pathogens
2.) Macrophages are found in large numbers in the following organs :
(i) Lung
(ii) Liver
(iii) Spleen
3.) Give two examples of each of the following:
(i) Killed organism vaccine : Typhoid vaccine, Pertussis vaccine.
(ii) Live attenuated organism vaccine : BCG, Rubella vaccine.
(iii) Toxoid vaccine: Diphtheria vaccine, Tetanus vaccine.
TERMINAL EXERCISE
1.) Define the term immunity.
Ans: The ability of the body to identify substances as foreign to itself and destroy, remove, or digest them with or without harm to its own tissues is known as immunity
2.) What are the main defence mechanisms operating in our body?
Ans: Our body has four defense mechanisms:
1.) The ability to fight illnesses and protect the body.
2.) The metabolizing and detoxifying power of the body.
3.) Bleeding control (haeostasis) to stop blood loss.
4.) Resistance to stress is mostly achieved by hormone release.
3.) ‘Immune system is a complex network of cells, tissues and soluble factors’.Justify this statement.
Ans: Immune system is complex network of cell , tissue , and soluble factors as cell such as B cells , T cells are requires for maintaining immunity other tissues and organ such as Thymus and bone marrow play a part of immune system.
4.) Describe the process of antibody production.
Ans: Antibody is produce by B cells in the body. B-cells are responsible for the production of antibodies. Activated B-cells transform into plasma cells, Some of the B-cells progeny do not differentiate into plasma cells but rather become ‘memory cells’ which produce antibodies in the event of the antigen re-appearing again in future.
5.) List main functions of T-cells.
Ans: T-cells’ primary responsibilities include (i) regulating immunological response.
(ii) Control the cell-mediated immune response (CMI) process.
(iii) stimulate B-cell production of antibodies.
6.) Draw a schematic diagram of the structure of antibody.
Ans:
7.) What are the main physical barriers of the body?
Ans: Skin: The keratin-based outer layer of skin is strong and nearly impervious to pathogens. Lactic acid produced by sebaceous glands in the skin creates an acidic environment that kills many bacteria.
Cilia covering the outer surface of the epithelial cells in the respiratory tract beat continuously upward toward the nasopharynx, helping to eliminate particles and bacteria. Epithelial cells regenerate continuously.and removing them eliminates germs encrusted on their surface.
Body secretions: Pathogens are repelled by body secretions like sweat and eye secretion. Other bodily fluids contain bactericidal chemicals that can eliminate microorganisms.
8.) Describe important features of phagocytic cells.
Ans: 1.) They quickly engulf the foreign molecular foreign agent with which they come into touch or with which they come into contact are important characteristics of phagocytic cells.
2.) They have enzymes that help break down the substance that is swallowed.
3.) They provide a crucial connection between innate and acquired immunity.
9.) Give one main difference between passively acquired immunity and actively acquired immunity.
Ans
Passively acquired immunity |
Actively acquired immunity |
It is transmitted from a person who has received an active vaccination by blood, serum components, etc. |
It is acquired through intentional artificial immunisation and infection, which causes the production of antibodies against the infectious agent. |
Some infections, such as diphtheria, whooping cough, smallpox and mumps usually induce a lifetime immunity |
Transfer of antibodies (e.g. IgG) from mother into foetus across the placenta |
10.) Define the process of attenuation.
Ans: Attenuation imitates the organism’s normal behaviour without actually making it sick. An ongoing supply of antigens is provided by the organism that is actively reproducing.
11.) Name two toxoid vaccines.
Ans: Toxoid vaccines : Examples: diptheria and tetanus.
Toxoid is a chemically or physically modified toxin that is no longer harmful but retains immunogenicity.
12.) What do the following abbreviations mean?
(i) BCG : Bacillo Calmette Guerin
(ii) DPT : diphtheria pertussis tetanus
(iii) MMR: measles, mumps and Rubella.
Also See: Chapter 1 Question Answer Solution