GCSE Combined Science Exam Study Guide (2027)
Everything the GCSE Combined Science (9-1) Exam tests, topic by topic: what each section covers, the facts that come up most, and how to study it. Pair it with the free 15-question practice test.
The exam at a glance
| Questions | AQA Trilogy: 6 written papers (2 biology, 2 chemistry, 2 physics), 70 marks each (420 marks in total). Edexcel 1SC0 and OCR Gateway J250: 6 papers of 60 marks each |
|---|---|
| Time | AQA: 7 hours 30 minutes in total (6 × 1 hour 15 minutes). Edexcel and OCR Gateway: 6 × 1 hour 10 minutes |
| Grades and pass mark | Graded on a 17-point double scale from 9-9 to 1-1; 4-4 is a standard pass and 5-5 a strong pass. Boundaries are set after every exam series, so aim for 70% in practice |
| Format | Written exams, calculator allowed on every paper, and a physics equation sheet is provided with the physics papers in 2027. Foundation tier (1-1 to 5-5) or Higher tier (4-4 to 9-9, with an allowed 4-3); all six papers at the same tier |
| Exam boards | AQA, Pearson Edexcel and OCR |
| Test provider | At your school or college, or as a private candidate at an exam centre that accepts them |
Mind map: the whole exam on one screen
Read the complete GCSE Combined Science study notes for “Cell Biology and Organisation”
Our first full set of comprehensive notes, about 18 minutes of reading: Cell structure · Microscopy and magnification · Cell division and stem cells · Moving substances: diffusion, osmosis, active transport · Enzymes and digestion · Food tests · The heart, blood and blood vessels · Plant tissues and transport, a worked exam example, the traps examiners use and a one-minute recap. Create a free account to read it and see how premium notes work before you decide.
1. Cell Biology and Organisation
Biology Paper 1 (AQA topics 1 and 2). Cell structure, microscopy, mitosis and stem cells, diffusion, osmosis and active transport, enzymes and digestion, food tests, the heart and blood, non-communicable disease and plant tissues.
Key facts
- Animal cells have a nucleus, cytoplasm, cell membrane, mitochondria and ribosomes; plant cells also have a cellulose cell wall, chloroplasts and a permanent vacuole. Bacteria (prokaryotes) have no nucleus: a single DNA loop plus plasmids.
- magnification = size of image ÷ size of real object (1 mm = 1000 µm). Electron microscopes have higher magnification and resolution than light microscopes.
- Mitosis produces two genetically identical cells for growth and repair. Stem cells are undifferentiated: embryonic stem cells can become most cell types, adult bone marrow stem cells form many types, and plant meristems can form any plant cell throughout life.
- Diffusion: net movement from higher to lower concentration. Osmosis: diffusion of water from a dilute to a more concentrated solution through a partially permeable membrane. Active transport: against the gradient, using energy from respiration.
- Enzymes are biological catalysts with an active site; high temperature and extreme pH denature them. Amylase (a carbohydrase) breaks starch into sugars, proteases make amino acids, lipases make fatty acids and glycerol. Bile neutralises acid and emulsifies fats.
- Food tests: Benedict's (sugars, blue to brick red when heated), iodine (starch, orange-brown to blue-black), Biuret (protein, blue to purple), ethanol (lipids, cloudy white emulsion).
- The heart is a double pump; the right side sends blood to the lungs and the left side to the body. Arteries have thick muscular walls, veins have valves, capillaries are one cell thick. Coronary heart disease is treated with stents and statins.
- In plants, xylem carries water and minerals up from the roots (transpiration) and phloem carries dissolved sugars both ways (translocation). Transpiration increases with temperature, light and air movement and decreases with humidity.
Flashcards
Exam tip: Learn the four biology food tests as reagent plus colour change. They come up as quick 1-mark questions and inside required practical questions.
2. Infection, Response and Bioenergetics
Biology Paper 1 (AQA topics 3 and 4). Communicable diseases and pathogens, human defences, vaccination, antibiotics and drug trials, photosynthesis and limiting factors, aerobic and anaerobic respiration, and metabolism.
Key facts
- Pathogens are viruses, bacteria, protists and fungi. Learn measles, HIV and tobacco mosaic virus (viral), salmonella and gonorrhoea (bacterial), rose black spot (fungal) and malaria (protist, spread by mosquitoes).
- Defences: skin, nose hairs, mucus and cilia in the airways, and stomach acid. White blood cells carry out phagocytosis and produce antibodies and antitoxins.
- Vaccines contain dead or inactive pathogens and trigger antibody production, so the response to the live pathogen is fast. Antibiotics kill bacteria but not viruses; painkillers only treat symptoms. Resistant bacteria such as MRSA spread when antibiotics are overused.
- New drugs are tested for toxicity, efficacy and dose, first on cells, tissues and animals, then in clinical trials on healthy volunteers and patients. Double-blind trials with placebos prevent bias.
- Photosynthesis: carbon dioxide + water → glucose + oxygen. It is endothermic. Limiting factors are light intensity, carbon dioxide concentration, temperature and the amount of chlorophyll; light intensity ∝ 1 ÷ distance² (Higher).
- Aerobic respiration: glucose + oxygen → carbon dioxide + water. Anaerobic respiration in muscles: glucose → lactic acid. In yeast: glucose → ethanol + carbon dioxide (fermentation).
- During exercise, heart rate, breathing rate and breath volume increase. Lactic acid causes an oxygen debt and is converted back to glucose in the liver.
- Metabolism is the sum of all reactions in a cell, including making starch, glycogen, cellulose, lipids and proteins, respiration, and making urea from excess protein.
Flashcards
Exam tip: On limiting-factor graphs, the factor on the x-axis is limiting where the line rises; where the line is flat, something else is limiting. Say which factor and why.
3. Homeostasis, Inheritance and Ecology
Biology Paper 2 (AQA topics 5 to 7). The nervous system and hormones, blood glucose and the menstrual cycle, meiosis, DNA, genetic crosses, evolution and classification, and ecosystems, sampling, cycles and biodiversity.
Key facts
- Homeostasis keeps internal conditions stable using receptors, coordination centres and effectors. Reflex arc: receptor → sensory neurone → relay neurone → motor neurone → effector.
- Blood glucose: insulin from the pancreas lowers it (glucose stored as glycogen); glucagon raises it (Higher). Type 1 diabetes: too little insulin; type 2: cells stop responding to insulin.
- Hormones in the menstrual cycle: FSH (egg matures), oestrogen (lining builds), LH (ovulation), progesterone (maintains lining). Contraception can be hormonal or non-hormonal. Adrenaline and thyroxine are Higher content.
- Meiosis makes four genetically different gametes with 23 chromosomes in humans. DNA is a double helix; a gene codes for a protein. Use Punnett squares with the terms dominant, recessive, homozygous, heterozygous, genotype and phenotype.
- Evolution by natural selection: variation, survival of the best adapted, reproduction and passing on of alleles. Evidence: fossils and antibiotic-resistant bacteria. Selective breeding and genetic engineering change organisms deliberately.
- Classification: kingdom, phylum, class, order, family, genus, species; three domains (Archaea, Bacteria, Eukaryota).
- Ecosystems depend on abiotic factors (light, temperature, moisture, soil pH) and biotic factors (food, predators, pathogens, competition). Quadrats estimate population size; transects show changes in distribution.
- Carbon cycle: photosynthesis removes CO₂; respiration, decomposition and combustion return it. Biodiversity is threatened by deforestation, pollution, peat bog destruction and global warming.
Flashcards
Exam tip: For Punnett squares, write the parents' genotypes, the gametes, the grid and the answer in the form the question asks (ratio, fraction or percentage).
Test yourself on these topics
Take the free 15-question GCSE Combined Science test, then save your results to unlock your Readiness Score and the mistakes bank.
4. Atoms, Bonding and Quantitative Chemistry
Chemistry Paper 1 (AQA topics 8 to 10). Atomic structure and history of the atom, isotopes, the periodic table and groups 0, 1 and 7, ionic, covalent and metallic bonding, structure and properties, conservation of mass, Mr, moles and concentration.
Key facts
- Atoms contain protons (+1, mass 1), neutrons (0, mass 1) and electrons (−1, very small mass). Atomic number = protons; mass number = protons + neutrons. Isotopes have the same number of protons but different numbers of neutrons. Atoms have a radius of about 0.1 nm.
- Models of the atom: Dalton's solid spheres, Thomson's plum pudding (electron), Rutherford's nuclear model (alpha scattering), Bohr's electron shells, then Chadwick's neutron.
Flashcards
Exam tip: Explain melting points in terms of what is broken: strong ionic or covalent bonds in giant structures, weak intermolecular forces in simple molecules. Never say covalent bonds break when a simple molecule melts.
5. Chemical Changes and Energy Changes
Chemistry Paper 1 (AQA topics 11 and 12). The reactivity series, extraction of metals, oxidation and reduction, acids, bases and salts, pH and neutralisation, electrolysis, and exothermic and endothermic reactions with energy profiles and bond energies.
Key facts
- Reactivity series (most to least): potassium, sodium, lithium, calcium, magnesium, carbon, zinc, iron, hydrogen, copper. Metals less reactive than carbon are extracted by reduction with carbon. Oxidation is gain of oxygen (or loss of electrons, Higher); reduction is loss of oxygen (or gain of electrons).
- Acids react with metals to give a salt + hydrogen, and with metal oxides, hydroxides and carbonates (carbonates also give CO₂). Hydrochloric acid makes chlorides, sulfuric acid makes sulfates, nitric acid makes nitrates.
Flashcards
Exam tip: In electrolysis, start by listing the ions present (including H⁺ and OH⁻ from water in solutions), then apply the rules for each electrode.
6. Rates, Organic Chemistry and Earth's Resources
Chemistry Paper 2 (AQA topics 13 to 17). Rates of reaction and equilibrium, crude oil, alkanes and cracking, chemical analysis (purity, formulations, chromatography, gas tests), the atmosphere and climate change, and using resources (potable water, life cycle assessments).
Key facts
- Mean rate = quantity of reactant used or product formed ÷ time. Rate increases with temperature, concentration (or gas pressure), surface area and catalysts. Collision theory: particles must collide with at least the activation energy. Catalysts provide a pathway with lower activation energy and are not used up.
- Reversible reactions reach equilibrium in a closed system when forward and backward rates are equal. Higher: Le Chatelier's principle predicts the effect of changing temperature, pressure or concentration.
Flashcards
Exam tip: For rate graphs, a steeper gradient means a faster rate. When asked to compare, refer to both the initial gradient and the final amount of product.
7. Energy, Electricity, Particles and Radioactivity
Physics Paper 1 (AQA topics 18 to 21). Energy stores and transfers, power and efficiency, energy resources, circuits and resistance, mains electricity, density and changes of state, specific heat capacity, atomic structure, radioactive decay and half-life.
Key facts
- Energy stores include kinetic (Eₖ = ½mv²), gravitational potential (Eₚ = mgh) and elastic potential (Eₑ = ½ke²). Energy is conserved; wasted energy is dissipated, often as heat.
- Power = energy transferred ÷ time (P = E ÷ t). Efficiency = useful output ÷ total input. Specific heat capacity: ΔE = mcΔθ.
Flashcards
Exam tip: Write the equation, substitute with units converted (kJ to J, minutes to seconds, g to kg), then calculate. Unit conversion is where most physics calculation marks are lost.
8. Forces, Waves and Magnetism
Physics Paper 2 (AQA topics 22 to 24). Scalars and vectors, resultant forces, work done, Hooke's law, motion graphs, Newton's laws, stopping distances, momentum (Higher), wave properties, the electromagnetic spectrum, magnets, electromagnets and the motor effect.
Key facts
- Scalars have magnitude only (speed, distance, mass); vectors have magnitude and direction (velocity, displacement, force). Weight W = mg, with g = 9.8 N/kg on Earth. Work done W = Fs.
- Hooke's law: F = ke, up to the limit of proportionality. The extension of a spring is directly proportional to the force applied.
Flashcards
Exam tip: In velocity-time graph questions, check whether you need the gradient (acceleration) or the area (distance). Split the area into rectangles and triangles and add them.
How to pass
- 70 marks in 75 minutes is just over 1 minute per mark. Short recall questions should take seconds, leaving time for 6-mark answers and calculations.
- There are 21 required practicals across the three sciences, and they are examined on the written papers. Learn the method, variables, risks and how to improve each one.
- Physics equations are printed on the equation sheet in 2027, but you still need to choose the right one, rearrange it and convert units such as kJ to J or minutes to seconds.
- Chemistry Paper 2 can draw on fundamental ideas from Paper 1 (atoms, bonding, moles), so keep revising Paper 1 chemistry after you have sat it.
- Your grade comes from the total across all six papers, so a weaker science can be balanced by a stronger one. Do not give up on any paper.
Frequently asked questions
How long should I study for the GCSE Combined Science exam?
Most students do best starting 10 to 12 weeks before the first paper, with 30 to 45 minutes a day per subject. You're ready once your Readiness Score has stayed at 80 or higher for about a week.
Can I take the GCSE Combined Science exam online?
No. GCSE Combined Science is a written exam sat in person at your school, college or an approved exam centre. Format: written exams, calculator allowed on every paper, and a physics equation sheet is provided with the physics papers in 2027. Foundation tier (1-1 to 5-5) or Higher tier (4-4 to 9-9, with an allowed 4-3); all six papers at the same tier. Check your exam board's timetable for dates.
What score do I need to pass the GCSE Combined Science exam?
Graded on a 17-point double scale from 9-9 to 1-1; 4-4 is a standard pass and 5-5 a strong pass. Boundaries are set after every exam series, so aim for 70% in practice. The exam has aqa trilogy: 6 written papers (2 biology, 2 chemistry, 2 physics), 70 marks each (420 marks in total). edexcel 1sc0 and ocr gateway j250: 6 papers of 60 marks each and a time limit of aqa: 7 hours 30 minutes in total (6 × 1 hour 15 minutes). edexcel and ocr gateway: 6 × 1 hour 10 minutes.
What are the most tested topics?
The outline covers cell biology and organisation, infection, response and bioenergetics, homeostasis, inheritance and ecology, atoms, bonding and quantitative chemistry, chemical changes and energy changes, rates, organic chemistry and earth's resources, energy, electricity, particles and radioactivity, forces, waves and magnetism. Use the free practice test to see which ones you need most.
The premium GCSE Combined Science study path
Premium GCSE Combined Science prep is studied one topic at a time. Each step starts with that topic's key notes and flashcard deck, then its own question sets of 25, so you master one topic before you move to the next. When every topic is strong, the 6 full mock exams show you're ready.
Your step-by-step study path
- 1Cell Biology and Organisation8 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25Notes free with an account
- 2Infection, Response and Bioenergetics8 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25Premium
- 3Homeostasis, Inheritance and Ecology8 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25Premium
- 4Atoms, Bonding and Quantitative Chemistry8 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25Premium
- 5Chemical Changes and Energy Changes7 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25Premium
- 6Rates, Organic Chemistry and Earth's Resources7 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25Premium
- 7Energy, Electricity, Particles and Radioactivity7 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25Premium
- 8Forces, Waves and Magnetism7 key notes, 100 flashcards, then 375 practice questions in 15 sets of 25Premium
- Final step: 6 full mock exams50 questions each, timed like exam day. Hit your target on them before your first paper.Premium
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Summarised from the exam boards' published specifications and the rules cited, checked November 2026. Confirm current requirements with AQA, Pearson Edexcel and OCR.