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Cells in immune system - class-XII

Description: cells in immune system
Number of Questions: 62
Created by:
Tags: immunity immune system soldiers of defense human physiology zoology cell biology and biotechnology biology
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Kupffer's cells are.

  1. Hormone secreting

  2. Fat cells

  3. Mast cells

  4. Phagocytic


Correct Option: D

Which of the following cells does not exhibit phagocytic activity?

  1. Monocytes

  2. Neutrophil

  3. Basophil

  4. Macrophage


Correct Option: C
Explanation:

Phagocytes have the ability to phagocytose or kill foreign cells and particles like pathogens by ingesting them. Many blood cells have this function, including monocytes, neutrophils and macrophages. Basophils do not have phagocytic activity.

Thus, the correct answer is 'Basophil.'

Collecting of WBCs at the site of injury occurs due to

  1. Phagocytotis

  2. Hemolysis

  3. Diapedesis

  4. All of the above


Correct Option: C
Explanation:
A. Phagocytosis is a process of cell eating in which a cell engulfs a particle and digests it.
B. Hemolysis is a process of rupture of red blood cells which release their contents into the blood plasma or any other surrounding fluid.
C. Diapedesis is the process of passage of WBCs or leucocytes from the capillaries towards the site of injury.
So, the correct answer is 'Diapedesis'.

Which of these are phagocytic in nature

  1. Neutrophil, monocyte and basophil

  2. Neutrophil, monocyte and macrophage

  3. Neutrophil, basophil and macrophage

  4. Acidophil, basophil and lymphocyte


Correct Option: B
Explanation:

Among the White blood cells (WBCs) four cells have the phagocytic ability. The neutrophils, monocytes, eosionophils and basophils. The basophils and the eosinophils have very less phagocytic ability when compared to the phagocytic ability of neutrophils and monocytes. When monocytes leave the blood and enter tissue spaces they grow and modify to form macrophages which still have the phagocytic ability. Thus, the correct option is B.

Heparin present normally in blood is formed by

  1. Granulocytes

  2. Clumped platelets

  3. Mast cell granules

  4. Monocytes


Correct Option: C
Explanation:
Mast cells are a type of white blood cells (WBCs) or leucocytes and contain many granules. Their granules are rich in heparin and histamine. They are formed from myeloid stem cells which are part of immune system. These cells release heparin which is an anticoagulant and prevents the clotting of blood in blood vessels by inactivating the clotting factors. Heparin is also released from basophils which are an another type of white blood cells.
So, the correct answer is 'Mast cell granules'.

What is the name given to a large amoeboid cell that engulfs and destroys bacteria invading the human body?

  1. Elastocyte

  2. Mast cell

  3. Macrophage

  4. T-cell


Correct Option: C
Explanation:

A macrophage is a type of phagocyte, which is a cell responsible for detecting, engulfing and destroying pathogens and apoptotic cells. Macrophages are produced through the differentiation of monocytes, which turn into macrophages when they leave the blood. Macrophages also play a role in alerting the immune system to the presence of invaders. Phagocytosis is the term used to describe the engulfing and destroying of defective or microbial cells. When inflammation occurs, monocytes undergo a series of changes to become macrophages and target cells that need eliminating. Once engulfed, cellular enzymes inside the macrophage destroy the ingested particle. Some macrophages act as scavengers, removing dead or necrotic cells while others provide host immunity by engulfing microbes.

So the correct option is 'macrophage'.

Antibodies are produced by

  1. Lymph nodes

  2. B lymphocytes

  3. Spleen

  4. Liver


Correct Option: B
Explanation:

An antibody also known as an immunoglobulin (Ig) is a large, Y-shaped protein molecule produced by B lymphocytes, that is used by the immune system to identify and neutralize pathogens (antigens) such as bacteria and viruses.

Therefore, the correct answer is option B.

Phagocytosis

  1. Is carried by cells of the adaptive immune system

  2. Is restricted to macrophages

  3. Is important in bacterial infections

  4. Is a process that does not involve energy


Correct Option: C
Explanation:

Phagocytosis is a process by which certain living cells called phagocytes ingest or engulf other cells or particles It is normally important in bacterial infections.

So, the correct option is 'is important in bacterial infections'

When human body is infected by infection ______________ type of cells are activated to defend the body.

  1. erythrocytes

  2. leukocytes

  3. lymphocytes

  4. monocytes


Correct Option: C

The blood cells which destroy disease causing germs are

  1. RBCs

  2. WBCs

  3. Platelets

  4. Haemoglobin


Correct Option: B
Explanation:

The cells involved in the immune system are white blood cells, or leukocytes, which destroy disease-causing organisms or substances. The two types of leukocytes are phagocytes and lymphocytes. The most common type of phagocyte is the neutrophil, which primarily fights bacteria. The two kinds of lymphocytes are B lymphocytes and T lymphocytes. Lymphocytes form in the bone marrow and either stay there and mature into B cells, or they leave for the thymus gland, where they mature into T cells.

Chief components of the immune system are

  1. Eythrocytes

  2. Thrombocytes

  3. Leucocytes

  4. All of the above


Correct Option: C
Explanation:

Leucocytes or the white blood cells are the disease-fighting white blood cells that identify and eliminate pathogens. Hence, they are one of the chief components of the innate immune system. A high white blood cell count is referred to as leucocytosis. The innate leucocytes include phagocytes (macrophages, neutrophils and dendritic cells), mast cells, eosinophils and basophils.

Therefore, the correct answer is option C.

Which of the following biotechnological product can enhance the immune system?

  1. IL-2

  2. GM-CSF

  3. TNF

  4. All of the above


Correct Option: D
Explanation:

Interleukin 2 (IL-2) is an interleukin, a type of signaling molecule that regulates the activities of white blood cells (leukocytes, often lymphocytes) that are responsible for immunity. Granulocyte-macrophage colony-stimulating factor (GM-CSF), also known as colony-stimulating factor 2 (CSF2), a monomeric glycoprotein secreted by macrophages, T cells, mast cells, NK cells, endothelial cells and fibroblasts that function as a cytokine -  a white blood cell growth factor and stimulate stem cells to produce granulocytes (neutrophils, eosinophils, and basophils) and monocytes. Monocytes exit the circulation and migrate into tissue, whereupon they mature into macrophages and dendritic cells. Thus, it is part of the immune system. Tumor necrosis factor (TNF) is a cell signaling protein (cytokine) involved in systemic inflammation and is one of the cytokines that make up the acute phase reaction. It is produced chiefly by activated macrophages. The primary role of TNF is in the regulation of immune cells. Thus, the correct answer is option D.

In humans, MHC is also known as

  1. APC.

  2. HLA

  3. Mast cells.

  4. None of the above.


Correct Option: B

Life of the effector cells of immune system is 

  1. A few weeks to several years

  2. A few days

  3. A few years

  4. A few months to whole life


Correct Option: B

Antigen presenting cells can be related to 

  1. Cell mediated immunity.

  2. Humoral immunity.

  3. Allergic reaction.

  4. None of the above.


Correct Option: A

The cells involved in defence against pathogens are

  1. Phagocytes

  2. T-lymphocytes

  3. B-lymphocytes

  4. All of the above


Correct Option: D
Explanation:

  • A T cell or T lymphocyte is a type of lymphocyte that plays a central role in cell-mediated immunity. T cells can be distinguished from other lymphocytes, such as B cells and natural killer cells, by the presence of a T-cell receptor on the cell surface. They are called T cells because they mature in the thymus.
  • B cells, also known as B lymphocytes are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system by secreting antibodies. B-cells bind to an antigen, receive help from a cognate helper T cell and differentiate into a plasma cell that secretes large amounts of antibodies and help in phagocytosis.
  • Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells.
So, the correct answer is 'All of the above'.

B- and T-cells required for immune system are produced in.

  1. Bone marrow

  2. Liver

  3. Spleen

  4. Lymph nodes


Correct Option: A
Explanation:
  • The acquired immunity involves two types of cells: B-cells and T-cells.T cells are involved in cell-mediated immunity, whereas B cells are primarily responsible for humoral immunity (relating to antibodies).
  • Like all blood cells, B(B lymphocyte)- and T-cells9T-lymphocyte) are produced in the bone marrow. B-cells mature in the bone marrow and  T-cells travel through the bloodstream to the thymus gland and mature in the thymus gland.
  • Hence B- and T-cells required for the immune system are produced in Bone marrow.
  • So, the correct answer is 'Bone marrow'.

Arrange the steps of ADA-deficiency treatment in sequence: 
I. The lymphocytes with ADA cDNA is returned to the patient
II. The lymphocytes from the blood of the patient are grown in culture outside the body 
III. A functional ADA cDNA (using retroviral vector) is introduced into the lymphocytes 

  1. $I\rightarrow III\rightarrow II$

  2. $I\rightarrow II\rightarrow III$

  3. $II\rightarrow I\rightarrow III$

  4. $III\rightarrow II\rightarrow I$


Correct Option: D
Explanation:

Adenosine deaminase deficiency or ADA deficiency is an autosomal recessive disorder that causes immunodeficiency. Gene therapy is a method to treat this. A functional ADA complementary DNA is inserted to the lymphocytes and then grown in an artificial culture. After the growth ADA cDNA is returned to the patient. 


So, the correct answer is 'III→II→I'.

MHCs are present as self antigens on all body cells except

  1. RBCs

  2. WBCs

  3. Lymphocytes

  4. Tissue cells


Correct Option: A
Explanation:

The major histocompatibility complex (MHC) is a collection of genes coding for MHC molecules found on the surface of all nucleated cells of the body. There are two classes of MHC molecules involved in adaptive immunity, MHC I and MHC II. MHC I molecules are found on all nucleated cells, they present normal self-antigens as well as abnormal or non-self pathogens to the effector T cells involved in cellular immunity. In contrast, MHC II molecules are only found on macrophagesdendritic cells, and B cells; they present abnormal or non-self pathogen antigens for the initial activation of T cells.

So, the correct option is 'RBCs'.

Which of the following does not belong with the others?

  1. Antigen - MHC forms

  2. Helper T-cell recognizes B- cell

  3. B-cell recognizes soluble antigen

  4. Antigen - presenting cell digests antigen


Correct Option: A
Explanation:

There are 2 forms of MHC, namely MHC class I and class II proteins. They play important role in the adaptive immunity. They present peptides on the cell surface for recognition by T cells. Helper T cells are part of adaptive immunity. They recognize and activate B cells to secrete antibodies and macrophages to destroy foreign bodies. They also help activate cytotoxic T cells to kill infected target cells. B cells are part of humoral immune response. They recognize soluble antigens. Antigen-presenting cell (APC) are those cells with detects, engulfs and digests antigen. 

Thus, the correct answer is 'Antigen - MHC forms.'

Identify the incorrect statement from the following.

  1. B-cells produce antibody

  2. Interferons kill viruses

  3. Response of T-cells is called cell mediated immunity

  4. Macrophages are the phagocytic cells.


Correct Option: A

Activation of B-lymphocytes is done by:-

  1. IgA

  2. IgG

  3. IgE

  4. IgD


Correct Option: D
Explanation:

IgD provides the activation signals to the B cells by acting as antigen receptors on the B cell surface. The B cells on being activated begins the immune defense mechanism of the body. So, the correct option is 'IgD'.

B-lymphocytes provide immunity by?

  1. Binding to antibodies

  2. Triggering Suppressor T cells

  3. Producing antibodies

  4. Producing antigens


Correct Option: C
Explanation:

B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system by secreting antibodies. BCRs allow the B cell to bind to a specific antigen, against which it will initiate an antibody response. They provide immunity by producing antibodies.

So, the correct option is 'producing antibodies'.

B-cells and T-cells of the body are involved in

  1. Defence mechanism

  2. Blood formation

  3. New bone formation

  4. Suppression of pain


Correct Option: A
Explanation:

T cells (thymus cells) and B cells ( bone marrow- or bursa-derived cells) are the major cellular components of the adaptive immune response. T cells are involved in cell-mediated immunity, whereas B cells are primarily responsible for humoral immunity (relating to antibodies).

So, the correct option is A. ( Defence mechanism )

When an organ is transplanted and is rejected by the body, the lymphocytes are produced by

  1. Cytotoxic T cells

  2. NK cells

  3. suppressor T cells

  4. B cells


Correct Option: A

How many followings statements are correct?
A. T-lymphocytes are part of acquired immunity.
B. Each antibody molecule has four pairs peptide chains, two pairs small called light chains and two pairs long called heavy chains.
C. Antibody-mediated immune response is responsible for graft rejection.

  1. Three

  2. Two

  3. Zero

  4. One


Correct Option: A

T-lymphocyte mature in

  1. Bone marrow

  2. Liver

  3. Thymus gland

  4. Kidney


Correct Option: C
Explanation:

T-lymphocytes are produced in bone marrow but differentiated in thymus glands. T lymphocytes play a central role in cell-mediated immunity. They can be distinguished from other lymphocytes, such as B cells and natural killer cells by the presence of a T-cell receptor  on the cell surface. They are called T cells because they mature in the thymus.

Histiocytes destroy bacteria by

  1. Phagocytosis

  2. Produces antitoxins

  3. Produces antibodies

  4. Produces antigen


Correct Option: A
Explanation:

Histiocytes destroy bacteria by phagocytosis. A histiocyte is an animal cell that is part of the mononuclear phagocyte system also known as the reticuloendothelial system or lymphoreticular system. The mononuclear phagocytic system is part of the organism's immune system. The histiocyte is a tissue macrophage or a dendritic cell.

Which of the following fights against the diseases?

  1. WBC

  2. RBC

  3. Liver

  4. Heart


Correct Option: A
Explanation:

WBCs fight against the infections. White blood cells account for only about 1 percent of the blood but their impact is significant. White blood cells, also called leukocytes, are essential for good health and protection against illness and disease. Think of white blood cells as your immunity cells. In a sense, they are continually at war. They flow through your bloodstream to battle viruses, bacteria, and other foreign invaders that threaten your health. When your body is in distress and a particular area is under attack, white blood cells rush in to help destroy the harmful substance and prevent illness. Thus, option A is correct. 

In the lymphatic system, .......... is the site for production of lymphocytes.

  1. Lymphoid organ

  2. Lymphoid walls

  3. Lymphoid tissue

  4. None of these


Correct Option: C
Explanation:

Associated lymphoid organs are composed of lymphoid tissue, and are the sites either of lymphocyte productionor of lymphocyte activation.

The main function of white blood cells in the body is to

  1. Carry oxygen

  2. Help in clot formation

  3. Produce more red cells

  4. Protect body against diseases


Correct Option: D
Explanation:

White blood cells or WBCs are also called leukocytes. They are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All leukocytes are produced and derived from a multipotent cell in the bone marrow known as a hematopoietic stem cell.

Therefore, the correct answer is option D.

................. manufactures antibodies.

  1. RBC

  2. WBC

  3. Plasma

  4. Platelets


Correct Option: B
Explanation:

WBCs or the white blood cells are the types of blood cells that are main cells of the immune system. The immune system responds to a particular pathogen to give you active or acquired immunity. The surface of every cell is covered with molecules that give it a unique set of characteristics. These molecules are called antigens. Antigens are generally fragments of protein or carbohydrate molecules. There are millions of different antigens and each one has a unique shape that can be recognized by the white blood cells of your immune system. The white blood cells then produce antibodies to match the shape of the antigens. Thus, option B is correct.

Clonal selection involves 

  1. Change in gene frequency

  2. Proliferation of T and B-cell

  3. Formation of dolly sheep

  4. Allergy


Correct Option: B
Explanation:

Clonal selection is a process to determine how B or T cell recognizes an antigen that enters the body is selected from the per-existing cell pool of differing antigen specificities and its proliferation to generate a clonal cell population that eliminates the antigen.
Thus, the correct answer is option B.

Exogenous antigens are processed and presented to the T-cells by 

  1. MHC I.

  2. MHC II.

  3. Mast cells.

  4. None of the above.


Correct Option: B

Which of the following matures in the thymus gland?

  1. B cell

  2. Fibrinogen

  3. Pathogen

  4. Phagocyte

  5. T cell


Correct Option: E
Explanation:

The thymus is the primary lymphoid organ where lymphocytes originate and/or mature. T-lymphocytes originate from lymphoid progenitor cells in thymus via three developmental stages, namely pro, pre and immature T cells. The immature T cells mature in thymus only. B cell originates and matures in red bone marrow, fibrinogen is the clotting factor 1 in blood and phagocytes are the type of WBC. Thus, the correct answer is E.

Which of the following is responsible for the production of antibodies specific to an infecting agent?

  1. B cell

  2. Fibrinogen

  3. Pathogen

  4. Phagocyte

  5. T cell


Correct Option: A
Explanation:

Phagocytes are the component of the non specific immune response. The encounter of B cell with a specific antigen activates its clonal expansion which in turn gives rise to plasma cell and memory cells.  A plasma cell is a mature B cell that serves in mass production of antibodies against a specific antigen. Pathogens are the disease-causing organisms that carry antigens. Fibrinogen is involved in the clotting process. T cells are responsible for cell-mediated immunity. Thus, the correct answer is A.

In which of the following organelle the MHC II molecule gets assembled before exogenous antigen processing?

  1. Lysosomes

  2. Endoplasmic reticulum

  3. Vacuoles

  4. None of the above


Correct Option: B
Explanation:
In the endoplasmic reticulum, during synthesis of class II MHC, the α and β chains are produced and complexed with a special polypeptide called invariant chain. The nascent MHC class II protein has its peptide-binding cleft blocked by the invariant chain to prevent it from binding cellular peptides or peptides from the endogenous pathway. The chain also aids the export of class II MHC from the Endoplasmic reticulum to the Golgi, followed by fusion with a late endosome containing endocytosed, degraded proteins. Thus the correct answer is option B.

During endogenous antigen processing, the antigens are cleaved in which of the following organelle?

  1. Endoplasmic reticulum

  2. Proteosomes

  3. Golgi bodies

  4. Lysosomes


Correct Option: B
Explanation:

The endogenous pathway is used to present cellular peptide fragments broken down by proteosomes on the cell surface of MHC class I molecules. Transporter associated with antigen processing spans the membrane of the rough endoplasmic reticulum and transports the peptides into the lumen of the rough endoplasmic reticulum. Once the peptide is transported into the ER lumen it binds to the cleft of the MHC class I molecule, stabilizing it and allowing it to be transported to the cell surface by the Golgi apparatus. Thus the correct answer is option B.

MHC genes in humans are located on 

  1. Chromosome 1.

  2. Chromosome 2.

  3. Chromosome 4.

  4. Chromosome 6.


Correct Option: D
Explanation:

Major histocompatibility complex (MHC) are the proteins on the surface of cell membrane. These proteins play an important role in the recognition of the foreign antigens. There are two MHC complexes called as MHC-I and MHC-II complex. These complexes play a different role in different processes. The genes for MHC complex are located on the chromosome 6 in the case of humans. In the case of mice, these genes are on chromosome 17. 

Thus, the correct answer is option D. 

MHC II is generally loaded with the 

  1. Extracellular protein.

  2. Intracellular protein.

  3. Cytosolic protein.

  4. None of the above.


Correct Option: A
Explanation:

MHC class II molecules bind peptides from antigens processed in organelles. These extracellular antigens, such as whole bacteria, engulfed by APCs via phagocytosis or endocytosis are enclosed in an intracellular vesicle. This vesicle containing peptides is fused with another vesicle containing MHC class II proteins. Upon fusion, the peptide is loaded onto MHC class II molecules, and the entire complex migrates to the cell membrane surface, where peptide-specific CD4 T cells recognize it. Thus the correct answer is option A.

Helper T-cells: Lymphokines as.
Killer T-cells: ____________.

  1. Interferons

  2. Lysozymes

  3. Perforins

  4. Prostaglandins


Correct Option: C

Types of T-cells are 

  1. Killer cells and helper cells

  2. Killer cells and suppressor cells

  3. Killer, helper and suppressor

  4. Killer, helper and dereppressor cells


Correct Option: C
Explanation:

  • A T cell, or T lymphocyte, is a type of lymphocyte that plays a central role in cell-mediated immunity. T cells can be distinguished from other lymphocytes, such as B cells and natural killer cells, by the presence of a T-cell receptor on the cell surface. They are called T cells because they mature in the thymus. 
  • The types of T-cells are killer cells (cytotoxic cells) which destroy virus-infected cells and tumor cells, and are also implicated in transplant rejection, helper T-cells which  assist other white blood cells in immunologic processes, including maturation of B cells into plasma cells and memory B cells, and activation of cytotoxic T cells and macrophages and suppressor T-cells which are crucial for the maintenance of immunological tolerance.
So, the correct answer is 'Killer, helper and suppressor'.

Both B-cells and T-cells of immune system are produced in

  1. Spleen

  2. Lymphoid nodes

  3. Bone marrow

  4. Thymus


Correct Option: C
Explanation:

Bone marrow is a semi-solid tissue which may be found within the spongy or cancellous portions of bones. Bone marrow is the primary site of new blood cell production or hematopoiesis. Bone marrow is considered as a primary lymphoid organ which is involved in the production and early clonal selection of lymphocyte tissues. Bone marrow is responsible for both the production of T cells and the production and maturation of B cells. 

So, the correct answer is 'Bone marrow'.

T-lymphocytes mature in

  1. Pancreas

  2. Spleen

  3. Bone marrow

  4. Thymus


Correct Option: D
Explanation:

The thymus is a specialized primary lymphoid organ of the immune system. The T-cells are produced from the bone marrow. Within the thymus, T cells mature. T cells are critical to the adaptive immune system, where the body adapts specifically to foreign invaders. The thymus is the largest and most active during the neonatal and pre-adolescent periods.

So, the correct answer is 'Thymus'.

T-cells have life of

  1. 4-5 days

  2. 4-5 weeks

  3. 4-5 months

  4. 4-5 years


Correct Option: D
Explanation:

A T cell or T lymphocyte is a type of lymphocyte that plays a central role in cell-mediated immunity. T cells can be distinguished from other lymphocytes, such as B cells and natural killer cells, by the presence of a T-cell receptor on the cell surface. They are called T cells because they mature in the thymus. Most lymphocytes are short-lived, with an average life span of a week to a few months, but a few live for years, providing a pool of long-lived T cells (4-5 years) and B cells.

So, the correct answer is '4-5 years'.

T-lymphocytes are 

  1. Formed in thymus

  2. Formed in bone marrow and mature in thymus

  3. Formed in thymus and preprocessed in bone marrow

  4. Formed and preprocessed in bone marrow


Correct Option: B
Explanation:

A T cell or T lymphocyte is a type of lymphocyte that plays a central role in cell-mediated immunity. T cells can be distinguished from other lymphocytes, such as B cells and natural killer cells, by the presence of a T-cell receptor on the cell surface. Lymphocytes such as B-cells and T-cells are produced in the bone marrow. They are called T- cells because they mature in the thymus.

So, the correct answer is 'Formed in bone marrow and mature in thymus'.

What is true about T-lymphocytes in mammals ?

  1. There are three main types-cytotoxic, helper and suppressor.

  2. They originate in lymphoid tissues.

  3. They scavenge damaged cells and cellular debris.

  4. They are produced in thyroid.


Correct Option: A
Explanation:

  • A T cell, or T lymphocyte, is a type of lymphocyte (a subtype of white blood cell) that plays a central role in cell-mediated immunity. T cells can be distinguished from other lymphocytes, such as B cells and natural killer cells, by the presence of a T-cell receptor on the cell surface. T-cells are originated from bone marrow and mature in the thymus gland. 
  • There are 3 main types of T-cells in mammals. They are - cytotoxic cells ( destroy virus-infected cells and tumour cells), helper cells (assist other WBC in immunologic processes including maturation of B cells into plasma cells and memory B cells, and activation of cytotoxic T cells and macrophages and suppressor cells (stop  T cell-mediated immunity toward the end of an immune reaction).
So, the correct answer is 'There are three main types-cytotoxic, helper and suppressor'.

Antigenic determinants are 

  1. Large and complex molecules that are different from those of an organism/host

  2. Proteins or carbohydrates

  3. Recognisable sites over antigens

  4. Specific products of pathogen


Correct Option: C
Explanation:

An epitope, also known as antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells. The part of an antibody that binds to the epitope is called a paratope. These epitopes interact with the paratope based on the 3-D surface features and shape or tertiary structure of the antigen.

So, the correct answer is 'Recognisable sites over antigens'.

Antigenic determinants are recognised by

  1. Antibodies

  2. Receptors over T-cells

  3. Receptors over B-cells

  4. All of the above


Correct Option: D

Which is not a T-lymphocytes?

  1. Helper

  2. Suppressor

  3. Cytotoxic

  4. Repressor


Correct Option: D
Explanation:
  • A T cell, or T lymphocyte, is a type of lymphocyte (a subtype of white blood cell) that plays a central role in cell-mediated immunity. T cells can be distinguished from other lymphocytes, such as B cells and natural killer cells, by the presence of a T-cell receptor on the cell surface. T-cells are originated from bone marrow and mature in the thymus gland. 
  • There are 3 main types of T-cells in mammals. They are - cytotoxic cells ( destroy virus-infected cells and tumour cells), helper cells (assist other WBC in immunologic processes including maturation of B cells into plasma cells and memory B cells, and activation of cytotoxic T cells and macrophages and suppressor cells (stop  T cell-mediated immunity toward the end of an immune reaction).
So, the correct answer is 'Repressor'.

What is true about Bt toxin ?

  1. The concerned Bacillus has antitoxins

  2. The inactive protoxin gets converted into active form in the insect gut

  3. Bt protein exists as active toxin in the Bacillus

  4. The activated toxin enters the ovaries of the pest to sterilize it and thus prevent its multiplication.


Correct Option: B

Anaplasia  is

  1. Transfer of cancer cells

  2. Formation of tumour

  3. Loss of cell adeherence and cell differentioation

  4. Action of lysosomes over cells


Correct Option: C
Explanation:

Anaplasia is a condition of cells with poor cellular differentiation, losing the morphological characteristics of mature cells and their orientation with respect to each other and to endothelial cells. Such loss of structural differentiation is especially seen in most, but not all, malignant neoplasms. Hence, Anaplasia is the loss of adherence and cell differentiation.

So, the correct answer is 'Loss of cell adherence and cell differentiation'.

B-lymphocytes differentiate and mature in

  1. Bone marrow

  2. Bursa of Fabricus

  3. Thymus

  4. Both A and B


Correct Option: D
Explanation:
  • B cell activation occurs in the secondary lymphoid organs, such as the spleen and lymph nodes. 
  • After B cells mature in the bone marrow, they migrate through the blood secondary lymphoid organs to which receive a constant supply of antigen through circulating lymph.
  •  In birds, the bursa of Fabricius is the site of hematopoiesis, a specialized organ that is necessary for B cell development in birds. 
  • Hence, B-lymphocytes differentiate and mature in Bone marrow and Bursa of Fabricius. 
  • So, the correct answer is 'Both A and B'.

Cytotoxic T-cells are similar to natural killler cells in secretion of 

  1. Interferons

  2. Lysozymes

  3. Perforins

  4. Prostaglandins


Correct Option: C
Explanation:
  • Perforin is a pore-forming cytolytic protein found in the granules of cytotoxic T lymphocytes (CTL) and Natural Killer cells (NK cells). 
  • Upon degranulation, perforin binds to the target cell's plasma membrane, and oligomerises in a Ca2+ dependent manner to form pores on the target cell.
  • Hence, Cytotoxic T-cells are similar to natural killer cells in the secretion of Perforins.
  •  So, the correct answer is 'Perforins'.

The site of production of ADA in the the body is _____________.

  1. Erythrocytes

  2. Lymphocytes

  3. Blood plasma

  4. Osteocytes


Correct Option: B
Explanation:

Lymphocytes are kind of white blood cells present in the bone marrow. ADA (adenosine deaminase) is an enzyme that is present in lymphocytes and is very important for the immune system to function. Its primary function in humans is the development and maintenance of the immune system.

T-cells in lymph nodes

  1. occur predominantly in the medullary region

  2. are only of the cytotoxic type

  3. are phagocytic

  4. are absent in Di George syndrome


Correct Option: D
Explanation:

T cells are so called because they are predominantly produced in the medullary region of thymus. They recognise  foreign particles (antigen) by a surface expressed, highly variable, T cell receptor (TCR). There are two major types of T cells: the helper T cell and the cytotoxic T cell. As the names suggest helper T cells ‘help’ other cells of the immune system, whilst cytotoxic T cells kill virally infected cells and tumours. T cells with CD4 molecules bind peptides displayed on MHC II molecules. As discussed earlier, such peptides are derived from phagocytized sources, and thus these T cells interact with only with certain special, phagocytic cells. 


So, the correct options are 'Option D'.

Production of antibody molecules by plasma cells requires interactions of and 

  1. Macrophages; plasma cells

  2. T-helper cells; B-cells

  3. Stromal cells; B-cells

  4. T-suppressor cells; plasma cells


Correct Option: B
Explanation:

Plasma cells are transported by the blood plasma and the lymphatic system. Plasma cells originate at the bone marrow and B cells differentiate into plasma cells that produce antibody molecules closely modeled after the receptors and requires interactions with Helper T cells.

So, the correct option is 'T-Helper cells: B cells'.

Arrange the following sentences in sequential order.
a) Antigen gets broken down into smaller fragments.
b) An antigen is internalised by phagocytosis.
c) An antigen is attracted by chemotaxis and attaches to the cell surface.
d) Antigen fragments binds to the MHC I and MHC II and gets transported to the membrane.

  1. b, c , a, d

  2. c, b, a, d

  3. b, c , d, a

  4. b, a , c, d


Correct Option: B
Explanation:
An antigen is attracted by chemotaxis and attaches to the cell surface of antigen-presenting cells, such as B-cells, dendritic cells and macrophages. This is followed by antigen processing that includes protein fragmentation (proteolysis) followed by its internalization. Then the antigen is phagocytosed. Its peptide fragments gets transported to the membrane and are expressed as peptide-MHC complex at the cell surface where they can be recognized by the T cell receptor ( TCR ) on a T cell. There are two classes of MHC proteins, MHC class I and MHC class II.
 So, the correct answer is ' c,b,a,d'

Plasma cells are

  1. inactive T-cells carried in the plasma

  2. B-cells that are actively secreting antibody

  3. formed from blood plasma

  4. the same as memory cells


Correct Option: B
Explanation:

Plasma cells are transported by the blood plasma and the lymphatic system. They originate in the bone marrow: B cells differentiate into plasma cells that produce antibody molecules closely modeled after the receptors of the precursor B cell.

So, the correct option is ' B cells that are actively secreting antibody'.

For a T-cell to recognize an antigen, it must interact with

  1. complement

  2. a macrophage

  3. a B-cell

  4. all of these


Correct Option: B
Explanation:

T cells must be activated by interacting with a professional APC presenting an antigen with their T cell receptor recognizes before they can divide and perform their function. For this, they must interact with a macrophage.

So, the correct option is 'A macrophage'.

Lymphocytes that activate B-cells and T-cells are

  1. macrophages

  2. cytotoxic T-cells

  3. activator B-cells

  4. helper T-cells


Correct Option: D
Explanation:

The three major types of lymphocyte are T cells, B cells and natural killer (NK) cells. Lymphocytes can be identified by their large nucleus. T helper cells(TH cells) assist other white blood cells in immunologic processes, including maturation of B cells into plasma cells and memory B cells and activation of cytotoxic  T cells and macrophages These cells are also known as CD4+ T cells because they express the CD4  glycoprotein on their surfaces. Helper T cells become activated when they are presented with peptide antigens by MHC class two molecules, which are expressed on the surface of antigen- presenting cells (APCs).


So, the correct option is 'Option D'.

Which of the following options is true regarding the B-cells?

  1. They are incapable of leaving lymph tissue to directly confronta foreign antigen

  2. Antibodies produced by B-cells travel in lymph and blood to react with the foreign antigens

  3. Some may develop into plasma cells that secrete antibodies

  4. All of the above


Correct Option: D
Explanation:

B- cells are the bone marrow cells which are the major components of the immune response. B-cells are produced in the bone marrow, they migrate to the spleen and other secondary lymphoid tissues. B-cells are responsible for generating antibodies to different antigens. 

So, the correct option is 'All of the above'.

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