RBSE Solutions For Class 12 Biology Chapter 39: Immune System | Textbook Important Questions & Answers

RBSE Class 12 Biology Chapter 39- Immune system. In this chapter, students can learn in detail about the immune system, types of the immune system, immunity, immunology, vaccination and types of vaccines. It also deals with natural immunity, acquired immunity, physical barrier, physiological barriers, autoimmunity, passive immunity, and much more.

These important questions help students to perform exceptionally well in their exams. By practising these important questions, students can analyze their preparation, get a thorough knowledge about all the important terminologies and perform their best in the examinations.

RBSE Solutions for Class 12 are the best study material for both class assignments and other board examinations. By practising these important questions, students can gain deep knowledge about the topics explained in this chapter and also help them to be well prepared for their upcoming examinations.

RBSE Class 12 Biology Chapter 39 Important Questions

RBSE Biology Chapter 39: MCQ Type Questions

Q.1. Which antibody is involved in hypersensitivity or allergic reaction?

(a) IgG

(b) IgA

(c) IgE

(d) IgM

Sol: (c) IgE.

Q.2. Which cell is involved in cell-mediated immunity?

(a) Leukaemia

(b) Mast cells

(c) T cells

(d) Thrombocytes

Sol: (c) T cells.

Q.3. Antigen is a _________.

(a) Sugar

(b) Aromatic

(c) Nucleic acid

(d) Protein

Sol: (d) Protein.

Q.4. Which antibody is transmitted from a mother placenta to embryo?

(a) IgG

(b) IgA

(c) IgE

(d) IgM

Sol: (a) IgG.

Q.5. Which of the following is produced in the body by vaccination?

(a) Toxoid

(b) Plasma

(c) Antibody

(d) Histamine

Sol: (c) Antibody.

Q.6. Which of the following is a physical barrier?

(a) Skin

(b) Body hair

(c) Eyelashes

(d) All of the above

Sol: (d) All of the above.

Q.7. The immunity obtained during lifetime is called _________.

(a) Active immunity

(b) Acquired immunity

(c) Passive immunity

(d) None of the above.

Sol: (b) Acquired immunity

Q.8. Vaccination are of _________types.

(a) Five

(b) Two

(c) Three

(d) Four

Sol: (c) Three.

Q.9. Which of the vaccines are created by the deactivation of pathogens?

(a) Toxoid vaccines.

(b) Conjugated vaccines

(c) Inactivated organism vaccine

(d) Attenuated vaccines

Sol: (c) Inactivated organism vaccine.

Q.10. Which of the following are long-term immunity, which is present since the time of our birth?

(a) Active immunity

(b) Innate immunity

(c) Passive immunity

(d) Acquired immunity

Sol: (b) Innate immunity.

RBSE Biology Chapter 39: Short and Long Answer Type Questions.

Q.1. What are the types of Immunity?

Sol: There are two major types of immunity:

  1. Innate Immunity or Natural or Non-specific Immunity.
  2. Acquired Immunity or Adaptive Immunity.

Q.2. Which part of the antigen binds with an antibody?

Sol: Fab- Fragment antigen binding is the part of the antigen that binds with an antibody.

Q.3. What is an Antigen?

Sol: An antigen is a molecule that initiates the production of an antibody and causes an immune response. Complete antigens and incomplete antigens.

Q.4. How many types of antigen and antibody are found in the human body?

Sol: There are two types of antigens and are classified based on their ability to function. There are five types of antibodies, which are classified according to their H chains.

Q.5. What are Antibodies?

Sol: Antibody (Ab) is also known as an immunoglobulin(Ig). These are large, Y-shaped proteins produced by plasma cells and are present in the blood cells. They bind to foreign particles and invade them. These particles are foreign bodies that get attacked by Antibody.

Q.6.What is Immunization?

Sol: Immunization is the process of activating the person’s immune system, typically by the administration of a vaccine. This process helps an individual to protect against subsequent infection or dreadful disease.

Q.7. What is Immunity?

Sol: Immunity is the ability of the body to defend itself against disease-causing organisms. Everyday our body comes in contact with several pathogens, but only a few result in diseases. The reason is, antibodies are released against these pathogens by our body cells, which has an ability to protect our body against diseases. This defence mechanism is called immunity.

Q.8. What are the main elements of the innate immune system?

Sol: The main elements of the innate immune system are –

  • Dendritic cells.
  • Phagocytic leukocytes.
  • Natural killer (NK) cell.
  • Physical epithelial barriers.
  • Circulating plasma proteins.

Q.9. What are the different types of antibodies?

Sol: Types of antibodies

Antibodies (Ab) are also known as an immunoglobulin(Ig). of five different types. This classification is on the basis of their H chains. The different types of antibodies that are present are as follows:

  1. Immunoglobulin A.
  2. Immunoglobulin D.
  3. Immunoglobulin E.
  4. Immunoglobulin G.
  5. Immunoglobulin M.

Q.10. What is the difference between antigen and antibody

Sol: An antigen is a molecule that initiates the production of an antibody and causes an immune response.

Antibody (Ab) is also known as an immunoglobulin(Ig). These are large, Y-shaped blood proteins produced by plasma cells. They bind to foreign particles and invade them. These particles are foreign bodies that get attacked by Antibody.

Differences between antigen and antibody.

Antigen Antibody
These are proteins but can be nucleic acids, carbohydrates and lipids. These are glycoproteins made up of small amounts of carbohydrates and amino acids.
Highly complex in structure and composition. Simpler in structure.
Causes diseases or allergic reactions. Protects the body against diseases.
These molecules interact with antibodies or by T-cell receptors when complexed with major histocompatibility complex. Synthesized by plasma cells of B cells that react with antigens who invoked their production.
Includes components of viral proteins, cell walls, capsules, and other microbes. Consists of 4 polypeptide chains, two light chains(L chain) and two heavy chains(H chain) forming a Y shape.
There are three basic kinds of antigens:

Exogenous.

Endogenous.

Autoantigens.

There are five basic kinds of antibodies:

IgM.

IgG.

IgE.

IgD.

IgA.

Q.11.What are the functions of the antibody?

Sol: The main functions of the antibody are:

  • Binds to pathogens
  • Assists in phagocytosis
  • Directly attacks viral pathogens
  • They ingest cells by phagocytosis.
  • Activates the immune system in case of bacterial pathogens
  • They also act as the first line of defence for mucosal surfaces.
  • It neutralizes the bacterial toxins and binds the antigen to enhance its efficiency.
  • Antibody provides long-term protection against pathogens because it persists for years after the presence of the antigen.
  • Few antibodies bind the antigen present on the pathogens. These aggregates the pathogen and they remain in secretions. When the secretion is expelled out, the antigen is also expelled.

Q.12. What is innate immunity?

Sol: The immunity, which is present in an organism by birth is called the innate Immunity. Innate immunity refers to the body’s defence system. This is activated immediately when the pathogen attacks. Innate immunity includes certain barriers and defence mechanisms that keep foreign particles out of the body. This immunity helps us by providing the natural resistance components including salivary enzymes, natural killer cells, intact skin and neutrophils, etc. which produce an initial response against the infections at birth prior to exposure to a pathogen or antigens. It is a long-term immunity in which our body produces the antibodies on its own. Our body has few natural barriers to prevent the entry of pathogens.

Q.13. What are the functions of antibodies in the human immune system?

Sol: Antibodies are the proteins produced due to the interaction of antigens with B cells found in the body and can get specifically coupled with that specific antigen.

Following are some of the primary functions of antibody:

  • It binds to pathogens.
  • It is involved in phagocytosis.
  • It directly attacks viral pathogens.
  • They ingest cells by phagocytosis.
  • It activates the immune system in case of bacterial pathogens.
  • They also act as the first line of defence for mucosal surfaces.
  • It neutralizes the bacterial toxins and binds the antigen to enhance its efficiency.
  • Antibody provides long-term protection against pathogens because it persists for years after the presence of the antigen.
  • Few antibodies bind the antigen present on the pathogens. These aggregate the pathogen and they remain in secretions. When the secretion is expelled out, the antigen is also expelled.

Q.14.What are the different types of antigens?

Sol: There are different types of antigens and the classification are as follows:

Based on their origin or their sources:

  1. Autoantigens.
  2. Exogenous antigens.
  3. Endogenous antigens.

Based on the immune response or the ability of antigens to carry out their functions:

  1. Complete antigens or Immunogens.
  2. Incomplete antigens or Haptens.

Q.15. What is the difference between active immunity and passive immunity

Sol: Active immunity and passive immunity are two types of adaptive immunity. A prominent difference between active and passive immunity is that active immunity is developed due to the production of antibodies in one’s own body, while passive immunity is developed by antibodies that are produced outside.

Differences between active immunity and passive immunity:

Active Immunity Passive Immunity
Active immunity is a permanent immunity produced by the antibodies of the host in response to direct contact of an antigen Passive immunity is a short-term immunity produced by the introduction of antibodies from outside to the host
Immunity doesn’t occur immediately. A time lag occurs for its development Immunity develops immediately. There is no time lag
There is an involvement of an immune system There is no involvement of an immune system
It generates an immunological memory Doesn’t generate immunological memory
Requires exposure to the pathogens Does not require exposure to the pathogens
No side-effects It may cause reactions
Provides long term protection. The protection is only transient
It involves both the humoral and cell-mediated immunity The immunity is conferred only by readymade antibodies
When the antigens enter the body naturally, antibodies and specialised lymphocytes are induced by the body Antibodies are passed from a mother to a fetus through the placenta and to an infant via mother’s milk.

Q.16. Explain in detail about the B-cells and T-cells.

Sol: The acquired immunity involves two types of cells: B-cells and T-cells. B cells and T cells are the white blood cells of the immune system that are responsible for adaptive immune response in an organism. Both the cells are produced or developed within the bone marrow. The B cells mature in the bone marrow and the T cells travel and mature in the thymus. These cells are structurally similar and are involved in adaptive immune response in an organism.

B-cells

  • B cells, also known as B lymphocytes.
  • B cells are a type of white blood cells, which are developed in the bone marrow.
  • The immunity dependent on B-cells is called humoral immunity.
  • These antibodies are attached to the surface of the antigen/foreign agent.
  • These antibodies function by detecting the antigen in the body and destroy it.
  • The B-cells are activated on their encounter with foreign agents. These foreign particles act as foreign markers.
  • The B-cells are differentiated into plasma cells which produce antibodies specific to that foreign particle or so-called antigen.

T-cells

  • T-cells also called T lymphocytes.
  • T-cells are one of the major components of the adaptive immune system.
  • The T-cells are originated in the bone marrow and developed in the thymus.
  • When these cells are triggered by an antigen, helper T-cells release cytokines that act as messengers.
  • The cytotoxic T-cells kills the cancer cells and the regulatory T-cells regulate immune reactions.
  • T-cells differentiate into helper cells, cytotoxic cells, and regulatory cells. These cells are released into the bloodstream.
  • These cytokines initiate the differentiation of B-cells into plasma cells which release antibodies against the antigens.

B-cells and T-cells

Q.17. What is Acquired Immunity?

Sol: Acquired Immunity

An individual acquires the immunity after the birth, hence is called the acquired immunity.

Acquired immunity, also called adaptive immunity.

Unlike the innate immunity, this is not present by birth. It is the immunity that our body acquires or gains over time. The ability of the immune system to adapt itself to disease and to generate pathogen-specific immunity is termed as acquired immunity. It is also known as adaptive immunity.

Acquired Immunity is specific and mediated by antibodies or lymphocytes which make the antigen harmless.

The main function of acquired immunity is to relieve the victim of the infectious disease and also prevent its attack in future. It mainly consists of an advanced lymphatic defence system, which functions by recognizing their own body cells and not reacting to them.

Our body starts producing antibodies to engulf the pathogen and destroy its antigen. When it encounters for the first time, it is called a primary response. Once a body gets used to these pathogens, antibodies are ready to attack them for the second time and are known as naturally acquired immunity.

The acquired immunity involves two types of cells: B-cells and T-cells

Features of Acquired Immunity

The acquired immunity in our body has certain special features.

  1. Specificity: Our body has the ability to differentiate between different types of pathogens, whether it is harmful or not, and devise ways to destroy them.
  2. Diversity: Our body can detect vast varieties of pathogens, ranging from protozoa to viruses.
  3. Differentiate between self and non-self: Our body has the unique ability to differentiate between its own cells and foreign cells. It immediately starts rejecting any foreign cell in the body.
  4. Memory: Once our body encounters a pathogen, it activates the immune system to destroy it. It also remembers what antibodies were released in response to that pathogen, so that, the next time it enters, a similar procedure is followed by the body to eliminate it.

Types of Acquired Immunity

Types of Acquired Immunity

Q.18. What is the physical barrier? List out the main physical barriers.

Sol: A human body has a few natural barriers to prevent the entry of pathogens.

The physical barrier functions by preventing the entry of disease-causing agents into the body. These include the skin, body hair, cilia, eyelashes, the respiratory tract, and the gastrointestinal tract. The physical barrier forms the first line of defence.

Skin

  • It is the first line of defence.
  • It is the outermost layer of the body which covers and functions as a protective barrier between the outside and the inside of the body
  • The outer layer of the skin, called epidermis, is dead due to the deposition of keratin protein and it forms a barrier layer. The germ cannot penetrate this layer.
  • The dermis has many sebaceous glands which secrete an oily secretion called sebum.
  • Sebum has lactic acid and fatty acid which maintain the pH of skin in between 3 to 5
  • Most of the microorganism does not survive in this pH and most of the bacteria also do not grow in this pH.

Mucous membrane

  • Many body organs such as the respiratory system, digestive system and reproductive system have a layer of epithelium cells, which are covered with a protective layer of mucus.
  • If the germ falls on this path, then they get destroyed in the protective mucus layer. It thus restricts the entry of such agents which may otherwise prove to be infectious.
  • The mucous membrane having an enzyme is called the lysozyme and they act as a germicidal.

Q.19. List out the similarities and differences between B-cells and T-cells?

Sol:

Similarities between B-cells and T-cells:

  1. Both B and T-cells are nucleated and motile.
  2. Both B and T-cells are types of lymphocytes.
  3. Both B and T-cells originate in the bone marrow.
  4. Both B and T-cells are involved in adaptive immunity.
  5. Both B and T-cells are non-phagocytic and are a part of the lymphatic system.
  6. Both B and T-cells protect the body’s immune system and help in fighting infections.

Differences between B-cells and T-cells:

B-Cells T-Cells
These cells are formed in the Bone marrow. These cells are formed in the Thymus.
B-Cells are also called B lymphocytes. T-Cells are also called T lymphocytes.
Present outside lymph node. Present inside the lymph node.
Surface antibodies are present. Surface antibodies are absent.
Have a shorter life span. Have a longer life span.
Secrete Antibodies. Secrete Lymphokines.
Only one active type of B-Cells. Two types of T-Cells: Helper and Killer.
Membrane receptor for antigen is BCR. Membrane receptor for antigen is TCR.
They connect to the surface of invading bacteria and virus. They connect only to the virus antigen on the outside.

Q.20. What are the cells involved in the mechanisms of innate immunity?

Sol: There are different types of cells, which play an important role in the mechanisms of innate immunity. These cells include:

  • Mast Cells: These are important for healing wounds and defence against infections.
  • Natural Killer Cells: These stop the spread of infections by destroying the infected host cells.
  • Eosinophils: These blood cells contain highly toxic proteins that kill any bacteria or parasite in contact.
  • Basophils: These blood cells attack multicellular parasites. Like the mast cells, these release histamine.
  • Neutrophils: These blood cells contain granules that are toxic in nature and kill any pathogen that comes in contact.
  • Phagocytes: These circulate through the body and look for any foreign substance. They engulf and destroy it defending the body against that pathogen.
  • Macrophages: These have the ability to move across the walls of the circulatory system. They release certain signals as cytokines to recruit other cells at the site of infections.
  • Dendritic Cells: These are located in the tissues that are the points for initial infections. These cells sense the infection and send the message to the rest of the immune system by antigen presentation.

We, at BYJU’S, aim to deliver students with all the necessary support and allow them to prove their abilities by excelling in their examination. Important Questions for RBSE Class 12 Biology Chapter-39, Immune system are prepared under the guidance of RBSE syllabus for Class 12 with proper structure and after thorough research on the particular topics.

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