Edexcel GCSE Biology Topic 5: Health, Disease and the Development of Medicines Exam Questions

About Edexcel GCSE Biology Topic 5: Health, Disease and the Development of Medicines

Topic 5 of Edexcel GCSE Biology is assessed on Paper 1. It defines health, explains how named pathogens cause and spread disease, and covers physical, chemical and immune defences, immunisation and antibiotics. GCSE Biology students also study the virus life cycle, plant defences, monoclonal antibodies (Higher tier) and the core practical on the effects of antibiotics or antiseptics on bacterial growth. The topic ends with drug development and non-communicable diseases, including cardiovascular disease, BMI and waist to hip ratio. Examiners often ask for disease spread and prevention, the primary and secondary immune responses, and BMI or clear zone calculations.

What you need to know

• Health and disease The WHO defines health as a state of complete physical, mental and social well-being, not merely the absence of disease. Communicable diseases are caused by pathogens and spread between people; non-communicable diseases are not. Diseases can interact, for example HIV weakening the immune system so TB develops.
• Named pathogens Cholera (bacterium, watery diarrhoea, spread in contaminated water), tuberculosis (bacterium, lung damage, airborne droplets), Chalara ash dieback (fungus, leaf loss and bark lesions), malaria (protist, mosquito vector), HIV (virus, body fluids), stomach ulcers (Helicobacter bacterium) and Ebola (virus, haemorrhagic fever, body fluids). Chlamydia and HIV are sexually transmitted.
• Human defences Physical and chemical barriers include skin, mucus and cilia in the airways, hydrochloric acid in the stomach and lysozyme in tears. Lymphocytes produce specific antibodies; memory lymphocytes give a faster, larger secondary response. Immunisation uses a harmless form of the antigen.
• Antibiotics and the core practical (Biology only) Antibiotics kill bacteria or stop their growth but do not affect viruses. Core practical: test antibiotics or antiseptics on agar plates using aseptic technique, measuring the clear zone and calculating its area with pi r^2.
• Plant defences and monoclonal antibodies (Biology only) Plants have physical (waxy cuticle, cell walls) and chemical (antiseptics, poisons) defences. Higher tier: monoclonal antibodies are made from hybridoma cells and are used in pregnancy tests, diagnosis and cancer treatment.
• Developing medicines New drugs go through discovery, preclinical testing on cells, tissues and animals, and clinical trials on healthy volunteers and then patients, often double blind with placebos, to check efficacy, toxicity and dosage.
• Non-communicable disease Risk factors include poor diet, smoking and alcohol (liver and brain damage). BMI = mass (kg) / height (m)^2 and waist to hip ratio indicate obesity. Cardiovascular disease is treated by lifestyle change, medication (such as statins) or surgery (stents, bypass, transplant).

Common mistakes in Topic 5: Health, Disease and the Development of Medicines

• Saying antibiotics treat viral infections. Antibiotics only affect bacteria.
• Saying the body remembers the disease. Memory lymphocytes recognise the specific antigen and produce antibodies quickly in the secondary response.
• Squaring the wrong value in BMI. Square the height in metres, not the mass.
• Using diameter instead of radius in pi r^2. Halve the diameter of the clear zone first.
• Saying vaccines cure diseases. Vaccines prevent infection by preparing the immune system in advance.

Try three Topic 5: Health, Disease and the Development of Medicines exam-style questions