AQA GCSE Combined Science: Trilogy Biology - overview of the seven biology topics
An overview of the biology content in AQA GCSE Combined Science: Trilogy (8464), mapping the seven biology topics from cell biology to ecology, how they are examined across Biology Paper 1 and Paper 2, and how to study them for top grades.
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The biology content of AQA GCSE Combined Science: Trilogy (specification 8464) is organised into seven topics. They make up the biology third of the award and are examined across two biology papers. This page maps the topics and links to a focused answer page for each.
The seven biology topics
- Cell biology
- Eukaryotic and prokaryotic cells, sub-cellular structures, specialisation and differentiation, microscopy and magnification, the cell cycle and mitosis, stem cells, and transport by diffusion, osmosis and active transport.
- Organisation
- The hierarchy of cells, tissues, organs and systems; enzymes and digestion; the heart, blood and blood vessels; coronary heart disease and health; and transport in plants.
- Infection and response
- Communicable diseases and pathogens, the body's defences, white blood cells and the immune system, vaccination, and antibiotics and drug development.
- Bioenergetics
- Photosynthesis as an endothermic reaction and its limiting factors, the uses of glucose, aerobic and anaerobic respiration, and the body's response to exercise.
- Homeostasis and response
- Control systems, the nervous system and reflexes, hormonal coordination by the endocrine system, control of blood glucose and diabetes, and reproductive hormones.
- Inheritance, variation and evolution
- Reproduction and meiosis, DNA and the genome, genetic inheritance and disorders, variation and mutation, evolution by natural selection, selective breeding and genetic engineering.
- Ecology
- Communities and competition, abiotic and biotic factors, adaptations, feeding relationships, the carbon and water cycles, biodiversity and human impact on ecosystems.
How the biology topics are examined
Biology in Combined Science is assessed by two written papers, each 1 hour 15 minutes and worth 70 marks:
- Biology Paper 1 covers topics 1 to 4 (Cell biology, Organisation, Infection and response, Bioenergetics).
- Biology Paper 2 covers topics 5 to 7 (Homeostasis and response, Inheritance variation and evolution, Ecology).
Each paper is one sixth of the overall Combined Science grade. Questions include multiple choice, structured, closed short answer and extended response.
How to study the biology topics
Biology rewards precise recall and clear application.
- Work from the specification statements. Each numbered point is a checklist; questions are written from them.
- Learn definitions exactly. Enzymes, diffusion, homeostasis and natural selection are marked on precise wording.
- Master the required practicals. Microscopy, food tests, osmosis and the effect of light on photosynthesis recur in the exams.
- Drill the maths. Magnification, rates and ratios appear in biology too.
- Practise six-mark questions. Extended responses reward a logical, well-linked argument.
For the official specification
AQA publishes the full specification, past papers and mark schemes at aqa.org.uk. Always revise from the current specification and AQA's own past papers, because question style is board-specific.