If you're on OCR Gateway Combined Science A (spec code J250), the double award, there are 16 compulsory Practical Activity Groups you need to know. OCR calls them "PAGs" rather than required practicals, and each PAG is a group of techniques: your school picks one activity from OCR's suggestions, or devises its own, provided it covers the apparatus and skills listed.
This guide walks through all 16 PAGs with the OCR letter-prefixed labels (B1 to B5 for Biology, C1 to C5 for Chemistry, P1 to P6 for Physics), flags which paper examines each one, and reconciles what gets dropped on Combined versus the three separate J247 Biology, J248 Chemistry and J249 Physics GCSEs. Different boards use different vocabulary for the same thing: OCR says "PAGs", AQA says "required practicals", Edexcel says "core practicals". This article is OCR Gateway A only. If you're on OCR Twenty First Century B (spec J260), use our OCR 21st Century Combined Science required practicals guide instead, the two OCR specs are very different.
This article was last checked against official sources on **14 October 2026**. Specifications and admissions wording change often, cross-check each named source before relying on specific detail.
OCR has TWO GCSE Combined Science specs: Gateway Science A (J250) and Twenty First Century B (J260). Different structures, different content framing, different paper counts. Both Combined specs use the same letter-prefixed PAG labels (B1 to B5, C1 to C5, P1 to P6); the main structural difference is the paper count (Gateway Combined uses 6 papers per tier, Twenty First Century Combined uses 4). Note the separate Gateway sciences use PAG 1 to PAG 8 (no letter prefix), so the same practical can carry different labels across the two suites, e.g. Combined B2 Sampling maps to separate Biology PAG 3. Check your spec code before revising.
All 16 OCR Gateway Combined Science PAGs
The table below lists every PAG on OCR Gateway Combined J250. OCR's own wording in the spec reads: "It is compulsory that learners complete at least sixteen practical activities. OCR has split the requirements from the Department for Education 'Combined science GCSE subject content' into sixteen Practical Activity Groups or PAGs: five biology, five chemistry and six physics."
Higher-tier paper codes run J250/07 to J250/12 (one Foundation set numbered 01 to 06). Each paper is 1 hour 10 minutes, 60 marks, and worth 16.7% of the overall grade. Biology sits on Papers 7 and 8, Chemistry on 9 and 10, Physics on 11 and 12. If you're choosing between Foundation and Higher tier, our tier choice guide explains how practical questions differ between the two.
| PAG | Title | Science | Papers |
|---|---|---|---|
| B1 | Microscopy | Biology | 7 and 8 |
| B2 | Sampling techniques | Biology | 7 and 8 |
| B3 | Rates of enzyme-controlled reactions | Biology | 7 and 8 |
| B4 | Photosynthesis | Biology | 7 and 8 |
| B5 | Microbiological techniques | Biology | 7 and 8 |
| C1 | Electrolysis | Chemistry | 9 and 10 |
| C2 | Distillation | Chemistry | 9 and 10 |
| C3 | Separation techniques | Chemistry | 9 and 10 |
| C4 | Production of salts | Chemistry | 9 and 10 |
| C5 | Measuring rates of reaction | Chemistry | 9 and 10 |
| P1 | Materials (density) | Physics | 11 and 12 |
| P2 | Forces (springs) | Physics | 11 and 12 |
| P3 | Motion (trolley acceleration) | Physics | 11 and 12 |
| P4 | Waves (ripple tank, reflection and refraction) | Physics | 11 and 12 |
| P5 | Energy (specific heat capacity) | Physics | 11 and 12 |
| P6 | Circuits (I–V characteristics; series and parallel) | Physics | 11 and 12 |
Because each PAG is a group of techniques rather than a single prescribed experiment, two schools may teach PAG B3 using slightly different enzyme experiments and both are valid. OCR publishes example activities for each PAG (for instance, catalase from potato or liver, or amylase and starch), but centres can substitute. When a question in the exam refers to a PAG, it tends to describe the apparatus and ask you to apply the technique, rather than naming a specific experiment.
How practical skills are assessed
There's no separate practical exam for OCR Gateway Combined. Instead, your centre submits a written practical science statement (part of the NEA Centre Declaration Form) confirming learners have had the opportunity to complete the PAGs. OCR's wording in the spec: "No less than 15% of the questions will assess practical skills." Practical-skills questions turn up on every one of the six papers. These sit mostly under AO2 (apply knowledge and understanding, 40% of the overall grade) and AO3 (analyse, interpret, evaluate, develop and improve experimental procedures, 20%), with AO1 (demonstrate knowledge) making up the remaining 40%.
The question styles OCR keeps coming back to look identical to the other boards: describe the method, identify independent / dependent / control variables, explain patterns in the results using scientific knowledge, and evaluate the method with specific improvements. Extended-response questions often draw on the quantitative PAGs (C5 rates, P3 motion, P5 energy, P6 circuits) where there's room to analyse data and interpret graphs.
Ready to boost your grades?
Join 1M+ students who have used Cognito to ace their exams.
Get started for free!
Combined vs Triple reconciliation
Combined J250 drops eight PAGs compared with the three separate OCR Gateway sciences. Triple totals: 8 Biology (J247) + 8 Chemistry (J248) + 8 Physics (J249) = 24. Combined totals: 5 + 5 + 6 = 16. Two of the Physics PAGs are merged rather than dropped outright (PAG 7 Series and parallel circuits folds into Combined P6, PAG 8 Interactions of waves folds into Combined P4). The rest are not required on Combined. OCR's own trimming follows Appendix 4 of the DfE's subject content.
| Science | Dropped from Triple → Combined | What it covers |
|---|---|---|
| Biology | PAG 2 Testing for biological molecules (separate J247) | Food tests for starch, reducing sugars, proteins and fats |
| Biology | PAG 6 Physiology, responses, respiration (separate J247) | Pulse rate / ventilation rate response to exercise |
| Biology | PAG 8 Transport in and out of cells (separate J247) | Osmosis in potato chips, water potential |
| Chemistry | PAG 1 Reactivity trend (separate J248) | Displacement reactions to establish Group 7 reactivity |
| Chemistry | PAG 5 Identification of species (separate J248) | Cation tests, anion tests, flame tests on unknown compounds |
| Chemistry | PAG 6 Titration (separate J248) | Strong acid vs strong alkali, concentration determination |
| Physics | PAG 7 Series and parallel circuits (separate J249) | Merged into Combined P6 as one circuits PAG |
| Physics | PAG 8 Interactions of waves (separate J249) | Merged into Combined P4 Waves (reflection off mirrors, refraction through prisms) |
If you're on Combined, don't revise food tests, exercise/physiology, osmosis in potatoes, Group 7 displacement reactions, flame tests or titration as dedicated standalone PAGs: Combined doesn't list them. Combined also merges separate Physics PAG 7 (series and parallel circuits) and PAG 8 (interactions of waves) into Combined's P6 Circuits and P4 Waves respectively. Some of the underlying science (osmosis theory, titration arithmetic, flame colours) can still turn up in Combined content, just not as a dedicated PAG.
Study tips for the 16 PAGs
Reading through the method isn't enough. PAGs test whether you can think like a scientist, not whether you can recite a recipe.
For each PAG, pick the specific activity your school ran, and write the method out from memory. Then check it against your notes. The steps you forgot are the ones that would have cost you marks. Pay attention to the small details OCR likes to probe: incubating microbiology plates at 25 degrees Celsius rather than 37, taping agar lids rather than sealing them, calculating Rf as substance distance over solvent distance, and reading voltmeters and ammeters at eye level to avoid parallax error.
For each PAG, prepare answers for the four question types that keep coming up: method, variables, explanation of results, evaluation and improvement. Practise the vocabulary of each: a specific improvement with a reason, not "repeat it".
Draw the graphs you'd expect for each quantitative PAG. For the rates PAG (C5), a curve that falls over time as reactants are used up. For the motion PAG (P3), a straight-line relationship between force and acceleration through the origin. For the circuits PAG (P6), the shape of I–V characteristics for an ohmic resistor (straight), a filament lamp (S-shaped) and a diode (zero in reverse, sharp rise after a threshold forward).
Work through past paper questions by PAG. OCR recycles both wording and graph shapes year on year, and the mark schemes are the clearest guide to the exact phrases they want. Our Year 11 mocks guide walks through how to prioritise PAG revision when you're balancing sixteen practicals against the rest of the spec.
On evaluation questions, OCR wants a specific weakness plus a specific improvement plus the reason it works. "Use a more accurate instrument" is half a mark. "Use a digital balance that reads to 0.01 g instead of 0.1 g to improve accuracy" is the full mark.
How Cognito helps
Our OCR Gateway GCSE Combined Science courses cover every one of the 16 PAGs through short video lessons, worked examples and exam-style questions. Each PAG has its own lesson walking through the technique, apparatus, variables and exam language. Head into the Combined Science Biology course, the Combined Science Chemistry course or the Combined Science Physics course and track your progress through the whole spec. If you want a sense of the full OCR Gateway Combined Science qualification before diving in, our complete guide to OCR Gateway GCSE Combined Science covers the paper structure and topic list end to end, and our grade 9 guide explains the exam technique needed for top marks.
