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Cambridge IGCSE Biology (0610/0970)
Chapter 10 - Diseases and immunity
Topic 10.1 - Diseases and immunity
For exams in 2023, 2024 & 2025 (core and extended)
As always this video follows the Cambridge syllabus exactly and contains absolutely everything you need to know for your final exam!
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@igpecomplete - Cambridge IGCSE PE
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Timestamps:
0:00 Contents
0:31 Pathogens and disease
0:56 Direct and indirect transmission
1:57 Body defences
2:45 Controlling spread of disease
4:36 Active immunity
5:35 Passive immunity
6:04 Vaccination
6:38 Cholera
Core content:
- Describe a pathogen as a disease-causing organism
- Describe a transmissible disease as a disease in which the pathogen can be passed from one host to another.
- State that a pathogen is transmitted:
(a) by direct contact, including through blood and other body fluids.
(b) indirectly, including from contaminated surfaces, food, animals and air.
- Describe the body defences, limited to: skin, hairs in the nose, mucus, stomach acid and white blood cells.
- Explain the importance of the following in controlling the spread of disease:
(a) a clean water supply
(b) hygienic food preparation
(c) good personal hygiene
(d) waste disposal
(e) sewage treatment (details of the stages of sewage treatment are not required)
Extended content:
- 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 put into the body.
(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 diseases.
- Explain that passive immunity is a short-term defence against a pathogen by antibodies acquired from another individual, including 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.
- Describe cholera as a disease caused by a bacterium which is transmitted in contaminated water.
- Explain that the cholera bacterium produces a toxin that causes secretion of chloride ions into the small intestine, causing osmotic movement of water into the gut, causing diarrhoea, dehydration and loss of ions from the blood.
