Infection and response – GCSE AQA Higher Biology revision notes

What this topic covers

Infection and response has 3 subtopics:

• Communicable diseases
• Monoclonal antibodies (biology only) (HT only)
• Plant disease (biology only)

Infection and response lessons by subtopic

17 lessons, grouped by subtopic.

Communicable diseases

• Types of Pathogens and How They Spread: Learn about the four main types of pathogens (viruses, bacteria, protists and fungi) and understand how infectious diseases spread through direct contact, water and air in both animals and plants.
• How Pathogens Cause Disease: Explore how bacteria and viruses reproduce rapidly in the body, how bacteria produce toxins that damage tissues, and how viruses live inside cells causing cell damage.
• Preventing the Spread of Disease: Discover the methods used to reduce or prevent the spread of infectious diseases in both humans and other organisms.
• How Vaccination Works: Learn how vaccines work by introducing inactive pathogens to stimulate white blood cell production of antibodies, and understand how the immune system responds quickly to prevent infection upon re-exposure to the same pathogen.
• Individual and Population Protection Through Vaccination: Explore how vaccination prevents illness in individuals and understand how immunising large portions of the population reduces the spread of pathogens through the community.
• Sources of medicines and their discovery: Learn about how medicines are traditionally sourced from plants and microorganisms, including famous examples like digitalis from foxgloves, aspirin from willow, and Fleming's discovery of penicillin. Explore how modern drug development combines traditional sources with synthetic chemistry.
• Testing new medicines: from laboratory to clinic: Understand the rigorous process of drug development including preclinical testing using cells, tissues and animals, followed by clinical trials with healthy volunteers and patients. Learn why extensive testing for toxicity, efficacy and dose is essential before medicines reach the public.
• Clinical trials and finding the right dose: Explore how clinical trials work, including why very low doses are used initially, how optimal doses are determined through further trials, and the importance of double-blind trials using placebos to ensure reliable results.

Monoclonal antibodies (biology only) (HT only)

• What are monoclonal antibodies and their key properties: Learn what monoclonal antibodies are, how they are produced from a single clone of cells, and understand their specific binding properties that allow them to target particular chemicals or cells in the body.
• The hybridoma technique for producing monoclonal antibodies: Explore the detailed process of creating hybridoma cells by combining stimulated mouse lymphocytes with tumour cells, and understand how these cells are cloned to mass-produce identical antibodies.
• Diagnostic and Laboratory Applications of Monoclonal Antibodies: Explore how monoclonal antibodies are used in pregnancy tests, hormone detection, pathogen identification, and research applications including fluorescent labeling techniques.
• Therapeutic Uses and Limitations of Monoclonal Antibodies: Investigate how monoclonal antibodies can be used to treat diseases like cancer by delivering targeted treatments, and examine the current limitations and side effects that affect their widespread use.

Plant disease (biology only)

• Physical Defence Responses in Plants: Students explore how plants use physical barriers and structures to defend against pathogens and herbivores, including cell walls, waxy cuticles, bark, thorns, and specialised movements.
• Chemical Defence Responses in Plants: Students investigate how plants produce and use chemical compounds to defend themselves, including antibacterial chemicals, toxins, and mimicry strategies to deter threats.
• Recognising Plant Disease Symptoms: Learn to identify the visual signs of plant diseases including growth problems, leaf changes, and pest damage. Explore specific diseases like tobacco mosaic virus, black spot, and aphid infestations.
• Methods for Identifying Plant Diseases: Discover different techniques for diagnosing plant diseases, from using gardening resources and laboratory testing to modern antibody-based testing kits.
• Mineral Deficiencies in Plants: Understand how lack of essential minerals affects plant health, focusing on nitrate deficiency causing stunted growth and magnesium deficiency leading to chlorosis.

Revise Right Mocks '26

AQA GCSE Biology mock draft, 26–31 Oct. Draft coverage: Biology Paper 1 (Higher tier). Reviewed for an original-practice sitting; check student availability before registering. Marking and results will follow later, after separate approval. Eligible new accounts receive a five-day Pro trial when signup email verification completes. Previous trials keep their original expiry. After expiry, new papers need Pro unless you have an explicitly confirmed free sitting offer for this event. That offer adds no Pro time or AI learning. Saved attempts and released results remain readable. No card or automatic charge.

More in this course

Go back to the full GCSE AQA Higher Biology topic list, or practise this topic with past-paper questions.