England · OCRSyllabus
Combined Science syllabus, dot point by dot point
Every dot point in the England Combined Sciencesyllabus, with a focused answer for each one. Click any dot point for a worked explainer, past exam questions, and links to related dot points. Written by Claude Opus 4.8, Anthropic's latest AI.
Biology: Scaling up
Module overview →- How does one cell become a whole organism through cell division, and what are stem cells used for?The cell cycle and mitosis producing two genetically identical cells, the role of mitosis in growth, repair and asexual reproduction, stem cells in embryos, adult tissue and plant meristems, and the use of stem cells in medicine and the ethics involved.9 min answer →
- How are eukaryotic and prokaryotic cells built, and how do we measure their tiny structures under a microscope?Eukaryotic and prokaryotic cells, the function of sub-cellular structures (nucleus, mitochondria, ribosomes, chloroplasts, cell wall, vacuole, plasmids), light and electron microscopy, the magnification equation, and the use of standard form and SI units for cell sizes.9 min answer →
- How do enzymes speed up the reactions of metabolism, and why do temperature and pH change how fast they work?Enzymes as biological catalysts, the lock and key model and the active site, the effect of temperature, pH and substrate concentration on enzyme activity, denaturing, and the breakdown of carbohydrates, proteins and lipids by digestive enzymes.9 min answer →
- How do cells release energy by respiration and how do plants make glucose by photosynthesis?Aerobic and anaerobic respiration and their word equations, photosynthesis as an endothermic reaction, the limiting factors of light intensity, carbon dioxide concentration and temperature, and the inverse square law relating light intensity to distance.9 min answer →
- How do substances move into and out of cells, and why do larger organisms need exchange surfaces?Diffusion, osmosis and active transport as ways substances move across membranes, the factors affecting the rate of diffusion, surface area to volume ratio, and the adaptations of exchange surfaces such as alveoli, villi and root hair cells.9 min answer →
- How do animals and plants move substances around their bodies through transport systems?The human circulatory system (heart, blood vessels and blood), the double circulation, the structure of arteries, veins and capillaries, the components and roles of blood, and transport in plants by xylem and phloem with transpiration and translocation.9 min answer →
Biology: Community level systems
Module overview →- How do organisms interact in ecosystems, and how are carbon and nitrogen recycled?Levels of organisation in an ecosystem, biotic and abiotic factors, interdependence and competition, the carbon cycle and the nitrogen cycle, decomposition, biodiversity, and human impacts on the environment.9 min answer →
- How is genetic information stored in DNA, and how are characteristics inherited from parents?DNA, genes and chromosomes, sexual and asexual reproduction, meiosis producing genetically varied gametes, dominant and recessive alleles, genotype and phenotype, Punnett squares and inheritance ratios, and inherited disorders.9 min answer →
- What causes disease, how does the body defend itself, and how are new medicines developed?Communicable and non-communicable diseases, types of pathogen and how they spread, the body's defences and the immune system, vaccination, antibiotics and the development and testing of new drugs.9 min answer →
- How do hormones coordinate the body more slowly than nerves, and how is blood glucose controlled?The endocrine system and the role of hormones, the control of blood glucose by insulin and glucagon, type 1 and type 2 diabetes, the reproductive hormones and the menstrual cycle, and a comparison of nervous and hormonal control.9 min answer →
- How does the nervous system detect and respond to changes, and how is the internal environment kept steady?The structure of the nervous system, the reflex arc and the role of synapses, receptors and effectors, the principle of homeostasis, and the control of body temperature, blood glucose and water as examples of negative feedback.9 min answer →
- Where does variation come from, and how does natural selection drive evolution?Genetic and environmental causes of variation, mutation, evolution by natural selection, evidence from fossils and antibiotic resistance, selective breeding, genetic engineering, and the work of Darwin.9 min answer →
Chemistry: Particles
Module overview →- What is an atom made of, and how do we describe atoms using atomic number and mass number?The structure of the atom (protons, neutrons and electrons), relative charges and masses, atomic number and mass number, isotopes, electronic structure, and the development of the model of the atom from Dalton to the nuclear model.9 min answer →
- How do atoms join together by ionic, covalent and metallic bonding to make compounds?Ionic bonding and the formation of ions, covalent bonding and shared electron pairs, metallic bonding and the sea of delocalised electrons, dot and cross diagrams, and how the type of bonding is decided by the elements involved.9 min answer →
- How does the particle model explain the three states of matter and the changes between them?The particle model of solids, liquids and gases, the arrangement and movement of particles in each state, changes of state and their names, the energy changes involved, and the limitations of the simple particle model.9 min answer →
- How does the structure and bonding of a substance explain its properties?The properties of ionic compounds, simple molecular substances, giant covalent structures (diamond, graphite, graphene) and metals, related to their structure and bonding, and the properties of nanoparticles and polymers.9 min answer →
- What is the difference between an element, a compound and a mixture, and how are mixtures separated?Elements, compounds and mixtures, the difference between mixtures and compounds, purity and formulations, and the separation techniques of filtration, crystallisation, simple and fractional distillation and chromatography.9 min answer →
- How is the periodic table organised, and how do the properties of the groups change?The arrangement of the periodic table by atomic number into groups and periods, the development by Mendeleev, the link between group number and outer electrons, and the properties and trends of Group 1, Group 7 and Group 0 elements.9 min answer →
Chemistry: Chemical reactions
Module overview →- How does passing electricity through an ionic compound break it down, and what is made at each electrode?Electrolysis of molten ionic compounds and aqueous solutions, the movement of ions to the electrodes, the products at the cathode and anode, the rules for aqueous electrolysis, and the use of electrolysis to extract reactive metals.9 min answer →
- Why do some reactions give out heat and others take it in, and how do we show this on an energy profile?Exothermic and endothermic reactions and everyday examples, temperature changes in reactions, reaction profile diagrams, activation energy, and the energy change in terms of breaking and making bonds.9 min answer →
- How can we identify the ions and gases present in a substance using chemical tests?Tests for the common gases (hydrogen, oxygen, carbon dioxide and chlorine), flame tests for metal ions, tests for carbonate, halide and sulfate ions, and the use of these tests to identify an unknown compound.9 min answer →
- How does the reactivity series let us predict displacement reactions and how metals are extracted?The reactivity series of metals, displacement reactions of metals and their salts, the reactions of metals with water and acids, the extraction of metals by reduction with carbon, and writing ionic and half equations.9 min answer →
- What controls the rate of a reaction, what is dynamic equilibrium, and how do we use moles to measure amounts?The factors affecting the rate of reaction (concentration, temperature, surface area, catalysts) and collision theory, the mole and concentration calculations, reversible reactions and dynamic equilibrium, Le Chatelier's principle, and the Haber process.10 min answer →
- What are the main types of chemical reaction, and how do acids and bases react?Word and balanced symbol equations, conservation of mass, the reactions of acids with metals, bases and carbonates, neutralisation, the pH scale, and oxidation and reduction in terms of oxygen and electrons.9 min answer →
Physics: Electricity and magnetism
Module overview →- What are current, potential difference and resistance, and how do series and parallel circuits behave?Circuit symbols, current as the flow of charge, potential difference and resistance, the equation V equals I times R, the I-V characteristics of components, and the rules for series and parallel circuits.9 min answer →
- What is the electromagnetic spectrum, and what are the uses and dangers of each type of radiation?The electromagnetic spectrum as a continuous range of transverse waves travelling at the speed of light in a vacuum, the order from radio waves to gamma rays, the uses of each region, and the dangers of the higher-energy waves.9 min answer →
- How do magnets and electric currents create magnetic fields, and how does the motor effect work?Permanent and induced magnets, magnetic fields and field lines, the magnetic field around a current-carrying wire and a solenoid, electromagnets and their uses, and the motor effect with the factors affecting the force.9 min answer →
- What is half-life, how do we calculate it, and how is radioactivity used and made safe?The definition of half-life, calculating the remaining activity after a number of half-lives, the uses of radioactive sources (medical tracers, treatment and dating), the difference between irradiation and contamination, and how to reduce the risks of radiation.9 min answer →
- What is radioactive decay, and how do alpha, beta and gamma radiation differ?The structure of the atom and isotopes, radioactive decay as a random process, the nature and properties of alpha, beta and gamma radiation, their penetrating and ionising power, and nuclear equations for alpha and beta decay.9 min answer →
- What are transverse and longitudinal waves, and how are wave speed, frequency and wavelength related?Transverse and longitudinal waves, the meaning of amplitude, wavelength, frequency and period, the wave speed equation, the relationship between frequency and period, and the reflection and refraction of waves.9 min answer →
Physics: Energy
Module overview →- How is energy stored and transferred, and why is the total energy always conserved?Energy stores and transfers, the conservation of energy, work done as energy transferred by a force, kinetic and gravitational potential energy, and the calculation of these energy stores.9 min answer →
- How do we describe motion using speed and acceleration, and read distance-time and velocity-time graphs?Scalar and vector quantities, distance, displacement, speed, velocity and acceleration, distance-time and velocity-time graphs, the equations of motion, and the meaning of gradient and area under a graph.9 min answer →
- How is electricity delivered through the national grid, and how do energy resources compare?The national grid and the role of step-up and step-down transformers, electrical power and energy calculations, the comparison of renewable and non-renewable energy resources, and the environmental and practical trade-offs involved.9 min answer →
- How do forces change motion through Newton's laws, and how do momentum and stopping distances work?Newton's three laws of motion, resultant force, weight and mass, the equation force equals mass times acceleration, momentum and its conservation, and stopping distance as the sum of thinking and braking distances.9 min answer →
- How does the particle model explain density, internal energy and the pressure of a gas?Density and its calculation, the particle model of the three states, internal energy and changes of state, specific heat capacity and specific latent heat, and the link between gas temperature and pressure.9 min answer →
- What is power, how do we measure efficiency, and how can we reduce wasted energy?Power as the rate of energy transfer, the equations for power, efficiency as the fraction of energy transferred usefully, the dissipation of energy, and ways to reduce unwanted energy transfers such as lubrication and insulation.9 min answer →