A-Level Biology
AS and A2 topic notes for CIE and Edexcel, the required practicals and walkthroughs of past papers.
About the exam
A Level Biology is a two-year course. The first year is the AS Level, which counts as a qualification on its own; the second year completes the full A Level. Most international schools follow Cambridge International (syllabus 9700) or Pearson Edexcel International A Level (IAL); the topics overlap a great deal, but the papers differ.
The table and units below follow Cambridge 9700 (syllabus for 2025–2027). For Edexcel IAL: Units 1 and 2 (AS) and 4 and 5 (A2) are theory papers worth 20% each, and Units 3 and 6 are written practical-skills papers worth 10% each.
Exam format
Paper 1: Multiple choice15.5%
40 questions on AS content
Time: 1 h 15
Paper 2: AS structured questions23%
60 marks on AS content
Time: 1 h 15
Paper 3: Advanced practical skills11.5%
Practical work and structured questions, 40 marks
Time: 2 h
Paper 4: A Level structured questions38.5%
100 marks on A Level content; AS knowledge is needed
Time: 2 h
Paper 5: Planning, analysis and evaluation11.5%
Written practical-skills paper, 30 marks
Time: 1 h 15
| Section | Questions | Time | Share of score |
|---|---|---|---|
| Paper 1: Multiple choice | 40 questions on AS content | 1 h 15 | 15.5% |
| Paper 2: AS structured questions | 60 marks on AS content | 1 h 15 | 23% |
| Paper 3: Advanced practical skills | Practical work and structured questions, 40 marks | 2 h | 11.5% |
| Paper 4: A Level structured questions | 100 marks on A Level content; AS knowledge is needed | 2 h | 38.5% |
| Paper 5: Planning, analysis and evaluation | Written practical-skills paper, 30 marks | 1 h 15 | 11.5% |
Percentages are shares of the full A Level. For the AS Level alone, Papers 1, 2 and 3 count 31%, 46% and 23%. Source: Cambridge 9700 syllabus for 2025, 2026 and 2027.
Syllabus topics (Cambridge 9700)
Unit 1: Cell structure
ASUnit 2: Biological molecules
ASUnit 3: Enzymes
ASUnit 4: Cell membranes and transport
ASUnit 5: The mitotic cell cycle
ASUnit 6: Nucleic acids and protein synthesis
ASUnit 7: Transport in plants
ASUnit 8: Transport in mammals
ASUnit 9: Gas exchange
ASUnit 10: Infectious diseases
ASUnit 11: Immunity
ASUnit 12: Energy and respiration
A LevelUnit 13: Photosynthesis
A LevelUnit 14: Homeostasis
A LevelUnit 15: Control and coordination
A LevelUnit 16: Inheritance
A LevelUnit 17: Selection and evolution
A LevelUnit 18: Classification, biodiversity and conservation
A LevelUnit 19: Genetic technology
A Level
Question types and strategy
Command words
Mark schemes reward exactly what the command word asks: state is a short answer, describe gives the pattern with data, explain gives the reason. See FRQ task verbs.
Structured questions
Use the marks as a guide: three marks usually means three separate points. Quote numbers from the figure when the question says use the data.
Practical papers
Draw tables with units in the column headings, give readings to a consistent number of decimal places, and plot graphs that fill more than half the grid.
Planning and statistics
Paper 5 asks you to plan an investigation and choose a statistical test: t-test, chi-squared, Pearson or Spearman correlation. See statistical tests.
AS & A2 topic notes
Topic notes for both years of the course.
Nothing here yet. New notes are added regularly.
Required practicals
Method, variables, risks and the questions examiners ask about each practical.
Nothing here yet. New notes are added regularly.
Past paper walkthroughs
Worked past-paper answers and what the command words expect.
Nothing here yet. New notes are added regularly.