How A Level Biology is Assessed: Cambridge 9700 vs. Edexcel IAL, One Practical Uses a Microscope While the Other is a Written Exam
Based on the official syllabuses for Cambridge International 9700 and Pearson Edexcel IAL Biology, this guide breaks down the paper structure, duration, marks, and weightings for both versions. Cambridge Paper 3 is a lab practical testing investigative experiments and light microscopes, while Edexcel Units 3/6 assess practicals through a written exam (18 core practicals). It covers AS and A Level topics, notes no major changes in the 2028–2030 Cambridge syllabus, and explains how to prepare for practicals, descriptions and explanations, data analysis, and English terminology.
A-Level Biology is a common subject for students applying to majors like medicine, life sciences, and psychology. The two main versions are Cambridge International 9700 and Pearson Edexcel IAL Biology. As with Physics and Chemistry, the biggest difference lies in the practical exams: Cambridge Paper 3 is taken in a lab and requires the use of a light microscope; Edexcel's practical units are written exams based on 18 core practicals.
Based on the official syllabuses of both exam boards, this article explains how the exams are structured and how to prepare. For the general rules on achieving an A* in A-Level, see How to Get an A* in A-Level; for exam seasons and registration, see How to Plan A-Level Exam Seasons and Registration.
1. Cambridge International 9700: Five Papers
| Paper | Content | Time / Marks | AS Weighting | A Level Weighting |
|---|---|---|---|---|
| Paper 1 | Multiple choice (40 questions, AS content) | 1 hour 15 mins / 40 marks | 31% | 15.5% |
| Paper 2 | AS structured questions | 1 hour 15 mins / 60 marks | 46% | 23% |
| Paper 3 | Advanced practical skills (lab practical) | 2 hours / 40 marks | 23% | 11.5% |
| Paper 4 | A Level structured questions | 2 hours / 100 marks | — | 38.5% |
| Paper 5 | Planning, analysis, and evaluation (written exam) | 1 hour 15 mins / 30 marks | — | 11.5% |
What to Expect in Paper 3
Paper 3 is a practical exam taken in a lab, consisting of 2–3 questions worth 40 marks in total. It includes two types of tasks:
- Investigative practical: Determine experimental techniques, collect quantitative or qualitative data, present data in tables and charts, analyze data (including calculations), draw conclusions, and suggest improvements or extensions to the experiment;
- Light microscope: Prepare slides, observe specimens, present observations appropriately, analyze data (including calculations), and draw conclusions.
The three available routes are the same as those for Physics and Chemistry: take AS only; complete A Level over two years; or take all five papers at once. Assessment objectives: Knowledge and understanding 40%, Handling, application, and evaluation of information 40%, Experimental skills 20%.
Content
AS (11 topics): Cell structure, biological molecules, enzymes, cell membranes and transport, the mitotic cell cycle, nucleic acids and protein synthesis, transport in plants, transport in mammals, gas exchange, infectious diseases, immunity.
A Level additions (8 topics): Energy and respiration, photosynthesis, homeostasis, control and coordination, inheritance, selection and evolution, classification/biodiversity and conservation, gene technology.
The new syllabus for 2028–2030 was released in September 2025, with official statements confirming no major changes that affect teaching.
2. Pearson Edexcel IAL Biology: Six Units
| Unit | Content | Time / Marks | IAS Weighting | IAL Weighting |
|---|---|---|---|---|
| Unit 1 | Molecules, Diet, Transport and Health | 1 hour 30 mins / 80 marks | 40% | 20% |
| Unit 2 | Cells, Development, Biodiversity and Conservation | 1 hour 30 mins / 80 marks | 40% | 20% |
| Unit 3 | Practical Skills in Biology I (written exam) | 1 hour 20 mins / 50 marks | 20% | 10% |
| Unit 4 | Energy, Environment, Microbiology and Immunity | 1 hour 45 mins / 90 marks | — | 20% |
| Unit 5 | Respiration, Internal Environment, Coordination and Gene Technology | 1 hour 45 mins / 90 marks | — | 20% |
| Unit 6 | Practical Skills in Biology II (written exam) | 1 hour 20 mins / 50 marks | — | 10% |
- The syllabus includes 18 core practicals (16 for Physics and Chemistry);
- At least 10% of the overall marks assess Level 2 or above mathematical skills (each unit has a minimum mark requirement, e.g., at least 8 marks in Unit 1);
- All six units are available in the January, June, and October exam series.
3. How to Prepare
Below are some practical recommendations based on our experience.
1. Practicals: Prepare According to Your Syllabus
- Cambridge: For Paper 3, you need hands-on practice with microscope operation, slide preparation, and biological drawing (clear lines, accurate proportions, standard labeling), as well as variable control and data processing for investigative practicals. Private candidates should confirm with the exam center whether practical exams can be arranged before registering;
- Edexcel: Master each of the 18 core practicals one by one: aim, variables, procedure, data processing, errors, and improvements.
2. Description and Explanation: Cover All Key Points
Many Biology questions ask you to describe, explain, or suggest. Ensure your answers cover all key points and use accurate terminology; use the mark schemes from past papers to see which points correspond to each mark.
3. Data Analysis
Both syllabuses test math skills: percentage change, ratios, magnification calculations, statistical tests (such as chi-square and t-tests, depending on syllabus requirements), and graph analysis. Do not neglect the calculations just because it is 'Biology'.
4. Cover Topics Less Emphasized in Local Schools
Topics such as immunity, infectious diseases, gene technology, classification and conservation, and control and coordination are taught at different depths in local high schools. Make sure to cover each point thoroughly according to the syllabus.
5. English Terminology
Biology involves a large amount of terminology: organelle, enzyme, substrate, transcription, translation, homeostasis, antibody, allele, natural selection, etc. Organize them by topic and practice spelling.
Final Thoughts
When choosing between Cambridge and Edexcel for A-Level Biology, the biggest difference lies in the practicals: Cambridge requires lab work (including microscopy), while Edexcel tests the 18 core practicals in a written exam. Combined with comprehensive descriptions and explanations, solid data analysis, and accurate English terminology, achieving an A* is entirely achievable with proper planning.
For other A-Level sciences, see A-Level Physics and A-Level Chemistry. If you need A-Level Biology tutoring, feel free to chat with our teachers.
Verification note: This article was verified against the official syllabuses in September 2026. The five papers, timing, marks, weightings, Paper 3 task structure (investigative practicals and light microscope), three exam routes, assessment objective weightings, and AS/A Level topics for Cambridge 9700 are from the Cambridge International AS & A Level Biology 9700 syllabus for 2025, 2026 and 2027; the statement that the 2028–2030 syllabus has "no major changes that affect teaching" is from the 2028–2030 syllabus; the six units, timing, marks, weightings, written format of practical units, 18 core practicals, math requirements, and exam series for Pearson Edexcel IAL Biology are from the Pearson Edexcel International A Level Biology Specification; the 16 core practicals each for Physics and Chemistry have been verified in articles 165 and 166 on this site. The examples of statistical tests and all preparation tips are based on our experience; please refer to the official syllabuses for final guidance.
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