2.4

Question 1

antigen

Answer 1

foreign molecule
stimulate immune response
antibody produced

Question 2

how are cells identified by immune system

Answer 2

each type of cell, specific molecules on surface that identify
often protiens with specific tertiary structure

Question 3

what type of cells can immune system identify

Answer 3

pathogens
toxins
cells from other organisms
abnormal body cells

Question 4

phagocytosis

Answer 4

Phagocyte attracted to pathogen by its chemicals and recognises its foreign antigens
engulfs it and surrounds it by its cell surface membrane
phagocyte contained in vesicle in cytoplasm of phagocyte
lysosome fuse with phagosome releasing lysozymes
lysozymes hydrolyse the pathogen

Question 5

the response of T lymphocytes to a foreign antigen

Answer 5

specific t helper cell with complementary receptors on its surface bind to antigen on
antigen-presenting cell
this activates it and they divide by mitosis to form clones which
phagocytes
cytotoxic t cells
specific B cells

Question 6

cytotoxic T cells

Answer 6

kill infected cells and tumour cells by producing perforin

Question 7

response of b lymphocytes to foreign antigen

Answer 7

colonel selection
specific b lymphocytes with comp receptor bind to antigen
stir by helper T cells
so divide by mitosis to form clones
Some differentiate into B plasma cells secrete large amounts of (monoclonal) antibody
Some differentiate into B memory cells → remain in blood for secondary immune response

Question 8

antibodies

Answer 8

quaternary structure protiens
secreted by b lymphocytes
bind specifically to antigen forming antigen antibody complex

Question 9

any

Question 10

primary immune response

Answer 10

first exposure to antigen antibodies produced slow at at low conc
takes time for specific b plasma cells to be stimulated to produce specific antibodies
memory cells produced

Question 11

secondary immune response

Answer 11

second exposure to antigen
antibodies produced faster and at a higher conc
b memory cells rapidly undergo mitosis to produce many plasma cells which produce specific antibodies

Question 12

vaccine

Answer 12

injection of antigens from attenuated pathogens
stimulating formation of memory cells

Question 13

how do vaccines provide protection against disease

Answer 13

specific b lymph with comp receptor binds to antigen

specific t helper cell binds to antigen presenting cell
stim b cell
B lymphocytes divide by mitosis = clones
some differentiate into b plasma cells which release antibodies
some differentiate into b memory cells
on secondary exposure to antigen b memory cells rapidly divide by mitosis to produce b plasma cells
these release antibodies faster and at a higher conc

Question 14

effect of antigen variability

Answer 14

antigen on pathogen change shape or tertiary structure due to gene mutation
no longer immune
b memory cell receptors cannot bind or recognise changed antigen on second exposure
specific antibodies not comp

Question 15

hiv replication

Answer 15

hiv AP attach to receptors on helper t cell
lipid envelope fuses with cell surface membrane releasing capsid into cell
capsid uncoats releasing rna and RT
RT convert viral RNA to DNA
viral dna inserted into helper t cell dna
viral protien capsid and enzymes produced
DNA transcribed into hiv mrna
hiv mrna translated to new hiv protiens
virus particles assembled and released from cell

Question 16

hiv causing symp of AIDS

Answer 16

hiv infect and kill helper t cells as it multiplies rapidly
so t helper cant stim cytotoxic t cells b cells and phagocytes
and B plasma cant release as many antibodies for destruction of pathogens
immune system more susceptible to infection
pathogens reproduce releasing toxins and damage cells

Question 17

why are antibiotics ineffective against virus

Answer 17

virus dont have metabolic processes
virus dont have murein cell wall

Question 18

monoclonal antibody

Answer 18

antibody produced from genetically identical plasma cells
so same tertiary structure

Question 19

monoclonal antibody use in medicine

Answer 19

they have specific tertiary structure
comp to receptor and only in specific cells
therapeutic drug attached to antibody
antibody binds to specific cell forming antigen antibody complex delivering drug

Question 20

medical diagnosis use of moncolonal antibodies

Answer 20

have specific tertiary structure
comp to specific antigen
dye attached to antibody
antibody binds to receptor forming antigen antibody complex

Question 21

antibody use in ELISA
to detect antigens

Answer 21

attach sample with potential antigens to well
add comp monoclonal antibodies with enzyme attached which bind to antigens if present
wash well to remove unbound antibodies
add substrate enzyme create products that change colour

Question 22

use of antibodies ELISA
to detect antibodies

Answer 22

attach specific antigens to well
add sample with potential antibodies and wash well
add comp monoclonal antibodies with enzymes attached
bind to antibodies if present
wash well to remove unbound antibodies
add substrate enzyme creates products that cause colour change

Question 23

ethical issues with use of vaccines and monoclonal antibodies

Answer 23

test on animals causing harm and stress
nut animals arent killed
clinical trial on humans can cause side effects

Question 24

active immunity

Answer 24

initial exposure to antigen
memory cells involved
antibody produced and secreted by b plasma cells
slow and take longer to develop
long term immunity as as antibody can be produced in response to specific antigen again

Question 25

passive immunity

Answer 25

no exposure to antigen
no memory cells involved
antibody introduced from another organism
faster acting
short term immunity as antibody hyrolysed

Question 26

explain why antibodies are only effective against specific pathogen

Answer 26

they have a specific tertiary structure thats only specific to complementary receptors on pathogen
forming antibody antigen complex

Question 27

role of macrophage in stimulating b lymphocytes

Answer 27

produce cytokinis

Question 28

structures within b lymphocyte to its functions

Answer 28

mitochondria provide ATP
RER synthesise proteins
b lymphocytes produce antibodies
golgi body produce glycoproteins

Question 29

how do vaccines provide immunity from pathogen

Answer 29

vaccine contains antigen from pathogen
t cell activate b cell
b cells divide by mitosis to form clones
plasma cells produce antibodies
memory cells produced meaning more antibodies produced and faster in secondary response

Question 30

how do vaccines produce antibodies against disease causing organism

Answer 30

vaccine contain antigens from pathogen
macrophage presents antigen on its surface
t cell with complementary receptor protein bind to antigen
t cell stimulate b cell and b cell secretes large amounts of antibody and divide to form clones

Question 31

role of antibodies in producing positive result in ELISA

Answer 31

first antibody binds to antigen which is complementary in shape
second antibody with enzyme attached added
2nd antibody attaches to antigen
substrate added causing a colour change

Question 32

explain why the first antibody or antibody a attach only to protein found in species

Answer 32

antibody has a specific tertiary structure
which is complementary to binding site on antigen

Question 33

why is antibody b or second antibody important

Answer 33

prevents false negatives
shows how antibody a or first antibody moves up strip

Question 34

how to pathogens cause disease

Answer 34

produce toxins
damage cells

Question 35

how do tests using monoclonal antibodies allow identification on stuff of harm and advantages

Answer 35

rapid treatment of infected cattle or carriers
can isolated infected and carriers
reducing spread of disease