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

Which of the following enzymes is responsible for inducing cleavage of a single double-stranded DNA molecule between the antigen receptor coding segment and a flanking recombination signal sequence?

  1. DNA-dependent protein kinase (DNA-Pk)

  2. Artemis nuclease

  3. Terminal deoxynucleotidyl transferase (TdT)

  4. Recombination activating gene (RAG)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

RAG enzymes work as a multi-subunit complex to induce cleavage of a single double-stranded DNA (dsDNA) molecule between the antigen receptor coding segment and a flanking recombination signal sequence.

Multiple choice

Which of these components of the blood is responsible for clotting?

  1. R.B.C.

  2. Lymphocytes

  3. Monocytes

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

Platelets (thrombocytes) are the blood components responsible for clotting - they gather at wound sites, release clotting factors, and form platelet plugs. RBCs carry oxygen, lymphocytes are white blood cells for immunity, and monocytes are also white blood cells that fight infection but don't directly clot blood.

Multiple choice

A person of blood group AB can receive blood from a person of

  1. only group B

  2. only group AB

  3. only group A

  4. any blood group
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The correct answer is 'any blood group' because persons with blood group AB are called 'universal recipients' - they have both A and B antigens on their red blood cells and no anti-A or anti-B antibodies. This means they can safely receive blood from any blood group (A, B, AB, or O) without having a transfusion reaction.

Multiple choice

In human body which cells fight against infection?

  1. Red blood cells

  2. Plasma

  3. White blood cells

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

The correct answer is white blood cells (leukocytes), which are the cells in the human body that fight infection. They are part of the immune system. Red blood cells carry oxygen, plasma is the fluid component, and hemoglobin is the oxygen-carrying protein in red blood cells.

Multiple choice

After 5 years of age, red blood cell production occurs in

  1. yalk sac

  2. liver

  3. bone marrow

  4. proximal end of tibia, humerus and flat bones

  5. vertebrae, sternum, ribs and iliac
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In proximal end of tibia, humerus and flat bones, red blood cells are formed after 5 years of age.