Biology

Human Immunity and Blood

2,096 Questions

Human immunity and blood questions cover the physiological mechanisms protecting the body against diseases and the components of blood. Topics include blood groups, cell mediated immunity, monoclonal antibodies, and blood coagulation. These biology topics frequently appear in general science sections of competitive exams.

Blood groupsCell mediated immunityMonoclonal antibodiesBlood coagulationCancer immunology

Human Immunity and Blood Questions

Multiple choice

Acute inflammation inside the body characteristically causes

  1. constriction of arterioles

  2. capillary endothelial cell enlargement

  3. influx of macrophages

  4. influx of neutrophils

  5. influx of mast cells
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Neutrophils are chemotactically attracted to the site of inflammation by C5a and mast cell chemotactic factors such as leukotriene B4.

Multiple choice

NK cells play a major role in the host-rejection of both tumours and virally infected cells. Which among the following does not characterise Natural Killer (NK) cells of the human body?

  1. Respond to interferon

  2. Contain perforin

  3. Kill only by damaging the target cell outer membrane

  4. Contain tumour necrosis factor (TNF)

  5. Contain serine proteases
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Perforin inserts into the target cell membrane, thereby facilitating entry of TNF and granzymes into the target cell.

Multiple choice

Which of the following lymphoid tissues is unencapsulated?

  1. Thymus

  2. Lymph node

  3. Spleen

  4. Tonsil

  5. MALT
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The respiratory, alimentary and genitourinary tracts are guarded immunologically by subepithelial accumulations of lymphoid tissues, which are not constrained by a connective tissue capsule. These may occur as diffuse collections of lymphocytes, plasma cells and phagocytes throughout the body and the lamina propria of the intestinal wall or as more clearly organised tissue with well-formed follicles as found in the Peyer's patches.

Multiple choice

A heavy chain is the large polypeptide sub-unit of a protein complex. The first immunoglobulin heavy chain class to be manifested on the surface of a newly produced B-cell in the body is

  1. IgA

  2. IgD

  3. IgE

  4. IgG

  5. IgM
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

IgM is the first immunoglobulin class to be expressed on the surface of the developing B-cells, shortly followed by IgD. Early mature B-cells co-express IgM and IgD antibodies of identical antigen specificity.

Multiple choice

Which of the following can be excluded from the functions of macrophages?

  1. Pinocytosis

  2. Phagocytosis

  3. Antigen processing

  4. T-cell priming

  5. Antigen presentation to activated cells
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Macrophages have an impressive range of functions, but appear unable to prime naive lymphocytes. This can be carried out by lymphoid interdigitating dendritic cells and cultured, but not freshly isolated, Langerhans' cells.

Multiple choice

Which among the following is a major factor in controlling the adaptive immune response of the body?

  1. Neutrophil

  2. Complement membrane attack complex

  3. C-reactive protein

  4. Antigen concentration

  5. Haptoglobin
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Lymphocytes are directly driven by antigen. The concentration of antigen is important because the binding to the surface of responding B-cells is necessary for continued stimulation. As the antigen concentration falls through catabolism or neutralisation or complex formation with antibody, the immune response diminishes. In this way, the immune response is not maintained at a high level when the antigen has been eliminated.

Multiple choice

Which of the following is the usual treatment of hemophilia A?

  1. Infusion of factor VIII as needed

  2. Blood transfusion

  3. Liver transplant

  4. Bone marrow transplant
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yes, it is the correct answer. Hemophila A is associated with episodes of bleeding. Current treatment involves infusion of factor VIII to promote blood clotting during a bleeding episode.

Multiple choice

Blood platelets are also known as 'thrombocytes'. Which of the following statements is correct for blood platelets?

  1. They are present in greater number than RBCs.

  2. They release main clotting factors in the blood.

  3. They will attach to the walls of damaged blood vessels.

  4. They conjoin in the presence of prostacyclin.

  5. Blood platelets bear a prominent nucleus, which regulates hemostasis and thrombosis.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In case of injury, the damaged endothelial cells lining the blood vessel release von Willebrand's Factor, which makes the surfaces sticky. The platelets start adhering to the surfaces of endothelial cells. This effect is called platelet adhesion.

Multiple choice

Pick the true statement regarding the ABO blood system.

  1. It was discovered in the 1950's.

  2. It was discovered by Karl Landsteiner.

  3. Determining ABO blood types is a difficult procedure.

  4. Type AB-negative is the universal donor.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Karl Landsteiner discovered the ABO system in 1900 and 1901, while trying to understand why blood transfusions sometimes saved lives and at other times caused death.

Multiple choice

Pick out the true statement regarding the antigen & antibody present in the blood, which helps in determining the blood group of the person.

  1. Individuals having A antigen will not produce the anti-A antibodies.

  2. AB types blood group individuals produce both anti-A and anti-B antibodies.

  3. AB type blood normally does not have either A or B antigens.

  4. O type blood contains both the antigens.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

If they produced anti-A antibodies, it would destroy their own blood. However, they do normally produce anti-B antibodies since B type blood would be alien to them.