Cells in the immune system

Question 1

Antigens

Answer 1

-Molecules that are typically proteins
-Found on the cell surface membranes
-Generate an immune response when detected by the body

Question 2

Foreign antigens

Answer 2

-Antigens that aren’t typically found in the body and will trigger an immune response when detected

Question 3

Types of foreign antigens

Answer 3

-Pathogens
-Abnormal body cells
-Toxins
-Cells from individuals of the same species

Question 4

Pathogens

Answer 4

-Organisms which cause disease (eg-viruses, bacteria, fungi)
-All have antigens on their surface which the body identifies as foreign

Question 5

Abnormal body cells

Answer 5

Cancerous/pathogen infected cells have abnormal antigens on their surface, which trigger an immune response

Question 6

Toxins

Answer 6

-Poisons
-They are a molecule not a cell
-Some are produced by bacteria
-The immune system responds to toxins and the pathogens that produce them
-The toxins themselves are the antigen

Question 7

Cells from individuals of the same species

Answer 7

-When cells are transplanted from a donor to a recipient, they have different antigens
-The body will see them as foreign, triggering an immune response
-This can be prevented by taking drugs to suppress the immune system

Question 8

Types of cells involved in the immune responses

Answer 8

-Phagocytes
-T-Cells
-B-Cells

Question 9

Phagocytes

Answer 9

-White blood cell that carries out phagocytosis
-Found in the blood and in tissues
-First cells to respond to an immune system trigger in the body

Question 10

What are the four main stages of immune response?

Answer 10

1) Phagocytosis
2) T-Cells
3) B-Cells
4) Antibody production

Question 11

Phagocytosis

Answer 11

-Phagocyte recognises the foreign antigens on a pathogen
-Phagocyte engulfs pathogen in its cytoplasm, forming a phagocytic vesicle
-Lysosome fuses to the vesicle, releasing lysozymes to destroy the pathogen
-The products of the pathogen are presented on the cell surface membrane of the phagocyte
-This activates other immune system cells

Question 12

T-Cells

Answer 12

-Also called a T-lymphocyte
-A type of white blood cell
-Has receptor proteins on its surface that bind to the complementary pathogens that bind to complementary antigens presented to it by phagocytes

Question 13

Helper T-Cells

Answer 13

-Release chemical signals that activate and stimulate phagocytes and cytotoxic T-Cells
-Kills abnormal and foreign cells
-Activate B cells

Question 14

B-cells

Answer 14

-Type of white blood cell
-Covered with antibodies
-Each have a different shaped antibody on its membrane, to bind to different antigens

Question 15

Clonal selection

Answer 15

-When antibody on a B-cell meets complementary antigen they bind
-This, as well as substances from helper T-cells activates the B cell
-The activated B-cells divide into plasma cells

Question 16

Antibody production

Answer 16

-Plasma cells are identical to B-cells, and secrete lots of antigens
-Called monoclonal antibodies, they bind to the pathogen to form antigen-antibody complexes