11.1 Defence against infectious disease – summary of mark schemes
11.1.3
Define active and passive immunity.
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11.1.4
active immunity – production of antibodies by the organism itself;
passive immunity – acquisition of antibodies from another organism / from elsewhere;
natural immunity – immunity due to infection / acquisition from mother;
artificial immunity – due to inoculation with vaccine / antibodies / vaccination;
Explain antibody production.
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11.1.6
antigens stimulate an immune response;
antibodies are produced in response to antigens;
antibodies are specific to antigen;
antibodies are made by B-cells / lymphocytes / plasma cells;
antigen is engulfed by macrophages;
antigen is presented on macrophage membrane;
helper T-cells bind to antigen (on macrophage);
helper T-cells are activated;
helper T-cells activate B-cells;
B-cells clone;
into plasma cells and memory cells;
plasma cells produce specific antibodies to the antigen;
memory cells for long-term immunity;
a faster / stronger response later;
Explain the principle of vaccination.
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vaccine is used (to induce immunity artificially);
vaccine contains dead / weakened / attenuated forms of the pathogen / bacterium / virus;
vaccine is injected / ingested;
booster shot may be needed;
immunity due to vaccination / immunisation lasts for life / a long period;
immunity to a disease is due to presence of the appropriate antibodies / cells that can make them;
active immunity is when the body makes the antibodies itself;
natural immunity is caused by exposure to a disease / pathogen / bacterium / virus;
antibodies are made in response to antigens / vaccine;
memory cells are made in response to antigens / vaccine;
11.1.7
Discuss the benefits and dangers of vaccination.
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benefits:
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prevent disease;
eliminate disease;
eg smallpox;
prevent epidemics;
healthier society;
reduce medical costs;
less job absenteeism;
disease free cattle / more food;
eradicate diseases / smallpox entirely;
prevent harm / disabilities due to diseases;
speed up the body’s response to a disease;
dangers:
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allergic reactions;
autoimmune response;
weakened virus becomes virulent / get disease;
danger of side-effects / example of side-effects;
vaccine with side-effects eg salk vaccine / whooping cough vaccine / MMR vaccine;