Keyword 3.0 Immunity

Question 1

Pathogen

Answer 1

A microorganism that causes disease.

Question 2

Antigen

Answer 2

Part of an organism or substance that is recognised as foreign by the immune system and stimulates an immune response (often antigens are protein molecules of the surface of cells.

Question 3

Phagocytosis

Answer 3

A mechanism by which cells engulf particles to form vesicles or vacuole (carried out by phagocytes as part of the body’s defence.)

Question 4

Lymphocyte

Answer 4

A type of white blood cell responsible for the immune response, there are two types; B and T. They are activated by the presence of antigens.

Question 5

Cell-mediated immunity (cellular response)

Answer 5

Part of the specific immune response involving T-lymphocytes being activated by antigen presenting cells. Helper T cells and cytotoxic T cells are involved.

Question 6

Humoral immunity

Answer 6

Part of the immune response that involves B lymphocytes (and antibodies) being activated through direct contact with antigens. Plasma cells and B memory cells are involved.

Question 7

Antibody

Answer 7

A ‘Y-shaped’ protein molecule produced by plasma cells in the response to an appropriate antigen. They cause agglutination of pathogens and acts as markers to stimulate phagocytosis.

Question 8

Vaccination

Answer 8

The introduction of antigens container in a vaccine into the body (usually by mouth of injection) to stimulate artificial, active immunity.

Question 9

HIV

Answer 9

The human immunodeficiency virus is a retrovirus (containing RNA) that can lead to disease AIDS (Acquired immune deficiency syndrome.) The HIV virus typically infects helper T cells preventing the immune system from functioning normally.

Question 10

ELISA test

Answer 10

The enzyme linked immunosorbent assay test uses antibodies to detect the presence and quantity of a protein in a sample. The test can be used to test a person from HIV and other pathogens.