Cambridge O Level Combined Science (5129): syllabus, papers and marking
November series only outside Brunei. Same Paper 2 and experimental-skills structure as the single sciences, so the marking follows the 5054 / 5070 / 5090 schemes once the combined rubric is released.
Syllabus for examination in 2026, 2027 and 2028 · November series · grades A*–E
Combined Science 5129: where the marks go
O Level Combined Science 5129 covers biology (12 topics), chemistry (10) and physics (5) in three papers: a 40-question multiple-choice Paper 1 (1 hour, 30 per cent), an 80-mark structured Paper 2 on all three sciences (1 hour 45 minutes, 50 per cent), and a 40-mark written Paper 3 on experimental skills (1 hour, 20 per cent). It is examined in November, and in June only in Brunei. A student is judged across three subjects in the time most spend on one, so the marks that go missing are mostly at the edges of topics.
Our papers follow the 2026–2028 structure and give each of the three sciences its proper share. Marking follows the conventions already used for 5054, 5070 and 5090: units and significant figures in physics, formulae and state symbols in chemistry, precise terminology in biology. The marking rubric for the combined paper is still being finalised.
Paper structure and what we mark
| Paper | Time | Marks | Weight | Questions |
|---|---|---|---|---|
| Paper 1 — Multiple Choice | 1 h | 40 | 30% | 40 compulsory four-option multiple-choice questions |
| Paper 2 — Theory | 1 h 45 min | 80 | 50% | Compulsory short-answer and structured questions across biology, chemistry and physics |
| Paper 3 — Experimental Skills and Investigations | 1 h | 40 | 20% | Written paper on experimental skills; no practical is performed |
Syllabus outline
- Biology: cells; enzymes; plant nutrition and transport; human nutrition; human gas exchange; respiration; transport in humans; drugs and their effects; coordination and control; development of organisms and continuity of life; biotechnology and genetic modification; relationships of organisms with one another and the environment
- Chemistry: states of matter; atoms, elements and compounds; stoichiometry; chemical energetics; chemical reactions; acids, bases and salts; the Periodic Table; metals; chemistry of the environment; organic chemistry
- Physics: motion, forces and energy; thermal physics; waves; electricity; nuclear physics
- Experimental skills and investigations (Paper 3)
How each paper is marked here
- Paper 1 is scored instantly and each wrong answer is mapped to the syllabus topic it tests, whichever science it belongs to.
- Paper 2 and Paper 3 are marked question by question, with the lost mark labelled as unit, equation, terminology or method so a pattern across the three sciences is visible.
- Paper 3 is a written paper on experimental skills; no practical is performed and none is marked.
Where Combined Science 5129 candidates lose marks
- Physics calculations without the unit — A correct number with a missing or wrong unit loses the final mark, and the same slip repeats on every calculation.
- Chemical equations without balancing or states — Chemistry marks go separately to formulae, balancing and state symbols. A word equation, where a symbol one was asked for, scores nothing.
- Biology answers that use everyday words — Using “food” where the scheme wants “glucose” or “starch”, or “goes through” where it wants “diffuses”, loses marks even when the idea is right.
- Experimental-skills answers that describe in general — On Paper 3, naming the independent and dependent variable, reading a scale to the correct precision, and plotting a graph accurately are credited. “Repeat to be fair” is not a precaution.
- Running out of time across three sciences — Because Paper 2 covers biology, chemistry and physics together, students who spend too long on a first topic leave later structured questions blank.
Sample papers, mark schemes and marked reports for 5129
See a real handwritten script marked by eight examiners at admitportfolio.com/examiners.
Questions teachers ask
- Is there a practical exam?
- No. Paper 3 is a written paper on experimental skills, so no practical work is carried out in the exam.
- Can I sit it in June?
- Only in Brunei. Elsewhere it is examined in November.
- How does it compare with the single sciences?
- It uses the same style of Paper 1 and Paper 2 but covers a narrower selection of topics from each science, and the third paper is written experimental skills rather than a choice of practical.
- Is this official Cambridge marking?
- No. Cambridge International Education marks the real exam. This is examiner-style marking of mocks and homework for 5129. Only you see the marking, and you decide what reaches the student.
- Do you reproduce past-paper questions?
- No. Every 5129 paper here is original and written to the syllabus for examination in 2026, 2027 and 2028, in the same structure as the real papers shown above.
- Which papers are marked?
- None yet are marked question by question; Paper 1 are scored instantly. Practical exams sat at the centre are not marked here.
- How is the next paper chosen?
- From the marks a student lost: the concepts behind them are ranked by marks dropped, and the new paper weights those topics. It is the same syllabus and structure, with new questions.
- When are the exams?
- November series. Grades A*–E.
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Start marking Combined Science scripts · See a real marked script