2. Immunity & Vaccines

Question 1

herd immunity

Answer 1

reduce occurrence of disease.

those not vaccinated less likely to catch disease.

Question 2

vaccines contain

Answer 2

antigens

free or attached to dead/attenuated pathogen

Question 3

disadvantage of taking vaccine orally

Answer 3

broken down by enzymes

could be too large to be absorbed into blood

Question 4

what do vaccines do

Answer 4

contain antigens
cause body to produce memory cells without pathogen causing disease
immune - no symptoms

Question 5

antigentic variation is caused by

Answer 5

changes in genes of pathogens

Question 6

why does antigenic variation cause you to get ill again

Answer 6

memory cells from 1st infection don’t recognise different antigens
has to carry out primary response

Question 7

e.g. of pathogens that show antigenic variation

Answer 7

influenza

HIV virus

Question 8

different antigens =

Answer 8

new strain of virus

Question 9

active immunity

Answer 9

immune system makes its own antibodies after being stimulated by an antigen
natural - immune after catching a disease
artificial - immune after vaccination

Question 10

passive immunity

Answer 10

given antibodies made by a different organism. own immune system doesn’t produce any.
natural - baby receives antibodies through placenta/breast milk
artificial - injected with antibodies from someone else

Question 11

active vs passive immunity

Answer 11

A requires exposure to antigen. P doesn’t
A takes while for protection to develop. P immediate protection
A memory cells produces. P not produced
A long term protection memory cells. P short term. antibodies broken down.