Immunity
12.3What the syllabus asks of you
- Describe active immunity as defence against a pathogen by antibody production in the body
- State that each pathogen has its own antigens, which have specific shapes
- Describe antibodies as proteins that bind to antigens leading to direct destruction of pathogens, or marking of pathogens for destruction by phagocytes
- State that specific antibodies have complementary shapes which fit specific antigens
- Explain that active immunity is gained after an infection by a pathogen, or by vaccination
- Outline the process of vaccination: (a) weakened pathogens or their antigens are given (b) the antigens stimulate an immune response by lymphocytes which produce antibodies (c) memory cells are produced that give long-term immunity
- Explain the role of vaccination in controlling the spread of transmissible diseases
- Explain that passive immunity is a short-term defence against a pathogen by antibodies acquired from another individual, limited to: across the placenta and in breast milk
- Explain the importance of breast-feeding for the development of passive immunity in infants
- State that memory cells are not produced in passive immunity
- Outline how HIV affects the immune system, limited to: decreased lymphocyte numbers and reduced ability to produce antibodies, which weakens the immune system
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Chapter 12: Immunity
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1Oct / Nov 2020 · Paper 11 · Q35Show mark scheme →
AOnly breast milk contains all the vitamins a growing baby needs.
BOnly breast milk contains antibodies.
COnly breast milk is sterile.
DOnly breast milk provides the correct volume of milk for the baby.
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