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 compound stabilize C3 convertase in this alternative pathway?

The alternative pathway of complement activation is triggered when a breakdown product of C3 hydrolysis, C3b is deposited on the surface of a microbe. Next step in this pathway is to form C3 convertase which enzymatically breaks down more C3.

  1. Factor D

  2. Properdin

  3. Histamine

  4. Cytokine

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

Properdine stabilizes the C3 convertase on microbial surface.

Multiple choice

Which of the following statements is false regarding spleen?

  1. It is placed in abdominal cavity.

  2. It is mesodermal in origin.

  3. It is also known as graveyard of RBCs.

  4. It is the largest lymph node.

  5. Its size decreases during malaria fever.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Spleen size increases during malaria fever due to increase in number of lymphocytes and dead RBCs.

Multiple choice

Which of the following statements is incorrect?

  1. Red blood cells are round and biconcave.

  2. Red blood cells lack nucleus.

  3. Red blood cells live for approximately four months.

  4. Red blood cells manufacture the antibodies that fight infection.

  5. Red blood cells are manufactured in the bone marrow.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This statement is incorrect. White blood cells manufacture the antibodies that fight infection. These are also known as the soldiers of the body.

Multiple choice

Fluoride is transported in blood through which of the following?

  1. Plasma

  2. RBCs

  3. RBCs and plasma

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

Flouride exists in both ionic and bound forms in the plasma with the bound form being present in larger quantity. The unbound or ionic forms vary according to the concentration of fluoride in drinking water. This form is asymmetrically distributed in blood between plasma and the blood cells.

Multiple choice

The site of RBC formation in a 20 year old healthy male is

  1. flat bones

  2. long bones

  3. liver

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

The bone marrow of essentially all bones produces red blood cells until a person is 5 years old. The marrow of the long bones, except for the proximal portion of the humeri and tibiae, becomes quiet and produces no more red blood cells after about an age of 20 years. Beyond this age, most red cells continue to be produced in the marrow of the membranous bones, such as the vertebrae, sternum, ribs and ilia. Even in these bones, the marrow becomes less productive as age increases.

Multiple choice

Which blood cells are responsible for humoral immunity?

  1. T cells

  2. B cells

  3. No cells, only antibodies

  4. Mostly B cells and sometimes T cells
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Humoral immunity comprises antibody formation against intracellular pathogens. This is principally mediated by B cells. T cells are involved in the cell-mediated immunity B cells are precursors of plasma cells. Lifespan of small B cells is less than 1 month.