CH12 immunity

Question 1

Active immunity

Answer 1

• immune system is activated and antibodies are formed

Question 2

Passive immunity

Answer 2

• antibodies are formed in one individual, extracted and injected into another

Question 3

Natural active immunity

Answer 3

• when meet a pathogen for first time, immune system is activated and antibodies formed
• immune system produces t and b memory cells
• if encounter pathogen again, immune system recognises antigens and pathogen can be destroyed immediately

Question 4

Natural passive immunity

Answer 4

• occurs with new born baby
• some antiodies cross placenta from mother to fetus whilst baby in uterus
• first milk is called colostrum, high in antibodies and infant gut allows them to pass into bloodstream

Question 5

Artificial passive immunity

Answer 5

• antibodies formed in one individual, extracted and injected into bloodstream of another individual

Question 6

Vaccines

Answer 6

• pathogen made safe so that antigens are intact but no infection risk
• small amounts of safe antigen are injected into blood
• primary immune response is triggered and body produces antibodies and memory cells
• come into contact again, secondary immune response is triggered and pathogen destroyed

Question 7

Benefit of vaccines

Answer 7

• prevent epidemics
• if large proportion of population vaccinated, gives herd immunity

Question 8

Why is there no malaria vaccine

Answer 8

• plasmodium is very evasive
• spends time inside erythrocytes so protected by self antigens from immune system
• within infected individual, antigens shuffle

Question 9

Why is there no hiv vaccine

Answer 9

• virus enters macrophages and t helper cells
• disables immune system itself