Immunity and Vaccines 2C

Question 1

What can help prevent a disease

Answer 1

A vaccine

Question 2

What do vaccines contain, and what do they do?

Answer 2

Vaccines contain antigens, which produce memory cells, against a particular pathogen without causing disease this means that you become immune without causing symptoms, these antigens may be free or attached to a dead or attenuated (weakened) pathogen

Question 3

Define herd immunity

Answer 3

Vaccine protect individuals that have had them, and because they reduce the occurrence of the disease, the people who are not vaccinated are also less likely to catch the disease because there are less people to catch it from

Question 4

How are vaccines administered

Answer 4

They are injected into the muscle or administered orally

Question 5

What are the disadvantages of an oral vaccine

Answer 5

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

Question 6

What do booster vaccines do?

Answer 6

Ensure that memory cells are being produced

Question 7

What does antigenic variation do

Answer 7

Helps some pathogens evade the immune system

Question 8

What do antigens do

Answer 8

Activate the primary response

Question 9

When is the secondary response stimulated

Answer 9

When you’re infected for a second time with the pathogen

Question 10

Define genetic variation

Answer 10

When a pathogen changes their surface antigens so when you are infected for a second time the memory cells will not recognise the different antigens so the immune system starts again with primary response, this could be due to mutations

Question 11

Examples where antigenic variation could take place

Answer 11

HIV and influenza virus

Question 12

How does antigenic variation affect the production of vaccines to prevent people catching influenza virus

Answer 12

The flu vaccine changes every year , this is because the antigens on the surface of the influenza virus change regularly forming new strains of the virus
Memory cells will not recognise the antigens of the new strain. The strains are immunologically distinct
This is why a new vaccine needs to be made every year so that they are most effective

Question 13

Describe active immunity

Answer 13

when your immune system makes its own antibodies

Question 14

Define natural active immunity

Answer 14

When you become immune after catching a disease

Question 15

Define artificial immunity

Answer 15

When you become immune after being given a vaccine containing a harmless dose of an antigen

Question 16

Describe passive immunity

Answer 16

When you are immune due to being given antibodies made by another organism as your immune system does not produce them on its own

Question 17

Define Natural passive immunity

Answer 17

When a baby becomes immune due to the antibodies it receives from its mother

Question 18

Define artificial passive immunity

Answer 18

When you become immune after being injected with antibodies from someone else

Question 19

Differences between active and passive immunity

Answer 19

Active immunity requires exposure to an antigen whereas passive immunity does not

In active immunity it takes a while for protection to develop whereas in passive immunity protection is immediate

In active immunity memory cells are produced whereas they are not produced in passive immunity

In active immunity protection is long term whereas in passive immunity is short term