cells and the immune system

Question 1

what triggers an immune response

Answer 1

foreign antigens

Question 2

what are antigens

Answer 2

molecules (usually proteins) found on the surface of cells, used by immune system to identify pathogens, abnormal body cells, toxins or cells from other individuals of the same species

Question 3

what are pathogens

Answer 3

micro-organisms that cause disease

Question 4

what are abnormal body cells

Answer 4

cells with abnormal antigens (e.g cancerous or pathogen-infected)

Question 5

4 stages of immune response

Answer 5

1) phagocyte engulfs pathogen
2) phagocyte activates T-cells
3) T-cells activate B-cells (which divide into plasma cells)
4) plasma cells make more antibodies to specific antigen

Question 6

phagocytes engulfing pathogens

Answer 6

1) phagocyte recognises foreign antigens a pathogen
2) cytoplasm of phagocyte moves around the pathogen and englufs it
3) pathogen is contained in phagocytic vacuole in phagocyte cytoplasm
4) lysosome fuses with phagocytic vacuole and breaks down the pathogen
5) phagocyte presents pathogens antigens on its surface to active other immune system cells (becomes antigen presenting cell)

Question 7

what is a phagocyte

Answer 7

type of white blood cell that carries out phagocytosis, found in blood and tissues, first cells to respond to an immune trigger

Question 8

what is phagocytosis

Answer 8

engulfment of pathogens

Question 9

phagocytes activating T-cells

Answer 9

the receptor proteins on the T-cell surface bind to the complimentary antigens present on phagocytes

Question 10

what are T-cells

Answer 10

type of white blood cell (t-lymphocyte)

Question 11

types of T-cells

Answer 11

helper T-cells, cytotoxic T-cells

Question 12

helper T-cells

Answer 12

release chemical signals that activate and stimulate phagocytes and cytotoxic T-cells, and activate B-cells

Question 13

cytotoxic T-cells

Answer 13

kill abnormal and foreign cells

Question 14

B-cells

Answer 14

type of white blood cell, covered with antibodies (each a different shape so bind to different antigens), secrete antigens, divides into plasma cells

Question 15

B-cells into plasma cells

Answer 15

1) antibody on surface of B-cell meets a complimentary antigen and binds to it to form an antigen-antibody complex
2) activates the B-cell (colonial selection)
3) activated B-cell divides into plasma cells

Question 16

plasma cells

Answer 16

secrete antibodies specific to the antigen (monoclonal antibodies) which bind to the antigens on the surface of the pathogen to form antigen-antibody complexes

Question 17

what are antibodies

Answer 17

proteins that have variable regions, coat pathogens to make them easier to be engulfed

Question 18

what is agglutination

Answer 18

pathogens that become clumped together (as antibodies have 2 binding sites)

Question 19

immune responses

Answer 19

cellular or humoral

Question 20

cellular response

Answer 20

T-cells and other immune system cells that they interact with (e.g phagocytes)

Question 21

humoral response

Answer 21

B-cells, colonial selection and production of monoclonial antibodies

Question 22

immune response for antigens

Answer 22

primary and secondary

Question 23

primary immune response

Answer 23

when antigen first enters body and triggers immune response, slow (as aren’t many B-cells, but eventually will come, until them symptoms are seen), afterwards B-cells produce memory cells

Question 24

what are memory cells

Answer 24

produced by B-cells, remain in body for a long time, record specific antibodies needed to bind the antigen and produce them quickly

Question 25

secondary immune response

Answer 25

if same pathogen enters body again, immune system will produce a quicker, stronger immune response (clonal selection), memory B-cells activated and divide into plasma cells that produce the right antibody, memory T-cells are activated and divided into correct T-cells, gets rid of pathogen before symptoms occur

Question 26

vaccines

Answer 26

dead or inactive forms of the pathogens that cause body to produce memory cells (become immune without symptoms)

Question 27

what do vaccines do

Answer 27

protect individuals, and create herd immunity

Question 28

what is herd immunity

Answer 28

people not vaccinated are less likely to catch the disease because there are fewer people to catch it from

Question 29

how are vaccines given

Answer 29

injected or taken orally

Question 30

disadvantage of taking orally

Answer 30

could be broken down by enzymes in the gut, or molecules of vaccine may be too large to be absorbed into the blood

Question 31

booster vaccines

Answer 31

sometimes given to ensure memory cells are produced

Question 32

antigenic variation

Answer 32

antigen changes shape (makes vaccination difficult), (e.g influenza virus = new strains that are immunologically distinct)

Question 33

immunity types

Answer 33

active or passive

Question 34

active immunity

Answer 34

when your immune system makes its own antibodies after being stimulated by an antigen 2 types - natural or artificial, requires exposure, takes a while for protection to develop, memory cells are produced, protection is long term

Question 35

natural active immunity

Answer 35

when you become an immune after catching a disease

Question 36

artificial active immunity

Answer 36

when you become immune after being given a vaccination

Question 37

passive immunity

Answer 37

immunity got from being given antibodies made by a different organism (when your immune system doesn't produce antibodies of its own) 2 types - natural or artificial, doesn't require exposure to antigen, protection is immediate, memory cells aren't produced, protection is short term

Question 38

natural passive immunity

Answer 38

when a baby becomes immune due to the antibodies it receives from its mother through the placenta and in breast milk

Question 39

artificial passive immunity

Answer 39

when you become immune after being injected with antibodies from someone else (e.g tetanus can be injected with antibodies against the toxin collected from blood donations)

Question 40

what are monoclonal antibodies

Answer 40

antibodies produced from a single group of genetically identical B-cells (plasma cells), identical in structure, made to bind to anything

Question 41

example - cancer cells

Answer 41

1) cancer cells have tumour markers that are not found on normal body cells 2) monoclonal antibodies can be made that will bind to the tumour markers , and anti-cancer drugs can be attatched ti the antibodies 3) when the antibodies come in contact with cancer cells they bind to the tumor markers, so drug will only accumulate in the body where there are cancer cells 4) side effects will be lower (as they accumulate near specific cells)

Question 42

pregnancy test

Answer 42

detect the hormone human chorionic gondotropin that's found in urine of pregnant women

Question 43

ELISA test

Answer 43

medical diagnosis that uses antibodies for things such as pathogenic infections

Question 44

ELISA test method

Answer 44

an antibody is used which has an enzyme attached to it, and the enzyme can react with a substrate to prduce a coloured product colour change = antigen is present

Question 45

types of ELISA test

Answer 45

direct and indirect

Question 46

direct ELISA test

Answer 46

uses a single antibody that is complimentary to the antigen you're testing for

Question 47

indirect ELISA test

Answer 47

uses 2 different antibodies

Question 48

ELISA test example

Answer 48

for HIV

Question 49

what is HIV

Answer 49

human immunodeficiency virus, causes AID's through affecting the immune system, no cure, replicates inside host cells

Question 50

ELISA test for HIV method

Answer 50

1) HIV antigen is bound to bottom of a well in a well plate 2)sample of patients blood plasma is added to the well 3)if there are any HIV specific antibodies, they will bind to the antigen , then the well is washed out 4)secondary antibody is added to the well, which can bind to the antibody and the well is washed out to remove any un-bound secondary antibody 5)a solution that contains substrate is added to the well which will react to the with the enzyme . if it changes colour = patient has HIV

Question 51

MMR

Answer 51

measles, mumps and rubella

Question 52

MMR scare

Answer 52

caused autism in children (insufficient testing - sample size of 12 children)

Question 53

herceptin

Answer 53

treat breast cancer - sample size of 1694

Question 54

ethical issues of vaccines

Answer 54

tested on animals, unnecessary risk for volunteers, side effects, who receives it first in an epidemic