Biology

Human Immunity and Blood

2,051 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

The antibodies in the blood are secreted by:

  1. Neutrophils

  2. Basophils

  3. Monocytes

  4. Lymphocytes
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Antibodies are proteins produced by specialized immune cells called B lymphocytes (B cells). Neutrophils, basophils, and monocytes are other types of white blood cells, but they do not produce antibodies - neutrophils are phagocytes, basophils release inflammatory chemicals, and monocytes become macrophages.

Multiple choice

The blood group with antibody A and antibody B is

  1. O

  2. AB

  3. A

  4. B
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Blood group O individuals have both anti-A and anti-B antibodies in their plasma because they lack both A and B antigens on their red blood cells. This is why O is the universal donor but can only receive O blood. AB has neither antibody, A has anti-B, and B has anti-A.

Multiple choice

Blood from a donor with AB group can be given to a person with

  1. A

  2. B

  3. AB

  4. O
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

People with AB blood type are 'universal recipients' - they have no anti-A or anti-B antibodies in their plasma, so they can receive blood from any group (A, B, AB, or O). However, AB donors can only give to other AB recipients. The question specifically asks where AB donor blood can go.

Multiple choice

Which of the following is affected by Leukemia?

  1. Bone marrow

  2. Brain

  3. Lymph node

  4. Blood cells
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Leukemia is a cancer of blood-forming tissues, primarily originating in bone marrow where abnormal white blood cells are produced. While it affects blood cells, the root cause and primary site is bone marrow dysfunction.

Multiple choice

Which of the following blood groups is a universal receiver group?

  1. A

  2. B

  3. O

  4. AB
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

AB blood group is the universal recipient because it has both A and B antigens on red blood cells but no anti-A or anti-B antibodies in plasma. This allows AB individuals to receive blood from any ABO group (A, B, AB, or O) without antibody-mediated rejection. Types A, B, and O can only receive from their own type or O (universal donor).

Multiple choice

Primary immunodeficiencies are disorders in which, part of the body's immune system is missing or does not function normally. Primary immunodeficiency, producing susceptibility to infection by viruses and molds is due to the

  1. B-cell deficiency

  2. T-cell deficiency

  3. phagocyte deficiency

  4. complement deficiency

  5. eosinophil deficiency
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Production of cytokines and of cytotoxic T-cells are important in the protective response.

Multiple choice

Natural killer (NK) cells are effector cells of the innate immune system and are important in the control of viral infections in the body. Which of the following statements is true regarding the classical NK cells?

  1. NK cells have rearranged T-cell receptor genes.

  2. NK cells are unaffected by IFN alpha.

  3. NK cells are more active against targets with upregulated MHC class I.

  4. NK cells can kill certain virally-infected cells.

  5. NK cells can kill all virally-infected cells.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Like cytotoxic T-cells, NK cells can inhibit viral replication by killing the host cell. The difference is that cytotoxic T-cells have a receptor for a specific T-cell epitope whereas NK cells have a broader specificity.

Multiple choice

What role does secreted phospholipases A2 play in immune system?

  1. Development of B and T lymphocytes

  2. Attraction of lymphocytes to infected site

  3. Chemoattractant

  4. Inflammation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

sPLA2 (Secreted phospholipases A2) have been shown to promote inflammation in mammals by catalysing the first step of the arachidonic acid pathway by breaking down phospholipids.