BiologyCode 5090
Immunity
What this topic asks you to be able to do
- Describe active immunity as protection against a pathogen through the body making its own antibodies
- State that every pathogen carries its own antigens, and that these have particular shapes
- Describe antibodies as proteins that attach to antigens, either destroying pathogens directly or tagging them so that phagocytes destroy them
- State that specific antibodies have shapes complementary to, and so fitting, the specific antigens they target
- Explain that people acquire active immunity following infection with a pathogen or through vaccination.
- Outline how vaccination works: weakened pathogens, or just their antigens, are administered, the antigens trigger lymphocytes to respond and make antibodies, and memory cells form to provide long-term immunity.
- Explain the part that vaccination plays in limiting the spread of transmissible diseases
- Explain that in passive immunity, antibodies obtained from another person give short-term defence against a pathogen, limited to: antibodies that cross the placenta and antibodies in breast milk
- Explain why breast-feeding matters for the build-up of passive immunity in infants
- State that passive immunity does not lead to the formation of memory cells
- Outline the effect of HIV on the immune system, limited to: a fall in lymphocyte numbers and in the ability to make antibodies, which leaves the immune system weaker