What you’ll learn17 learning objectivesChoose one objective for a focused lesson, or study the complete topic.10.1.1Pathogen as a disease-causing organism• Describe a pathogen as a disease-causing organismSyllabus objective10.1.2Transmissible disease as a disease• Describe a transmissible disease as a disease in which the pathogen can be passed from one host to anotherSyllabus objective10.1.3Pathogen is transmitted: (a) by direct• 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 airSyllabus objective10.1.4Body defences• Describe the body defences, limited to: skin, hairs in the nose, mucus, stomach acid and white blood cellsSyllabus objective10.1.5Controlling disease spread• 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)Syllabus objective10.1.6Active immunity as defence against• Describe active immunity as defence against a pathogen by antibody production in the bodySyllabus objective10.1.7Each pathogen has its own antigens• State that each pathogen has its own antigens, which have specific shapesSyllabus objective10.1.8Antibodies as proteins that bind• Describe antibodies as proteins that bind to antigens leading to direct destruction of pathogens or marking of pathogens for destruction by phagocytesSyllabus objective10.1.9Specific antibodies have complementary• State that specific antibodies have complementary shapes which fit specific antigensSyllabus objective10.1.10Active immunity is gained after• Explain that active immunity is gained after an infection by a pathogen or by vaccinationSyllabus objective10.1.11Process of vaccination: (a) weakened• 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 immunitySyllabus objective10.1.12Role of vaccination in controlling• Explain the role of vaccination in controlling the spread of diseasesSyllabus objective10.1.13Passive immunity is a short-term• 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 milkSyllabus objective10.1.14Importance of breast-feeding• Explain the importance of breast-feeding for the development of passive immunity in infantsSyllabus objective10.1.15Memory cells are not produced• State that memory cells are not produced in passive immunitySyllabus objective10.1.16Cholera as a disease caused• Describe cholera as a disease caused by a bacterium which is transmitted in contaminated waterSyllabus objective10.1.17Cholera bacterium produces a toxin• 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 bloodSyllabus objective