Biology Revision: WJEC GCSE Science (Double Award) (teaching from 2016)
This guide is for the legacy qualification taught from 2016. The page shows Biology requirements plus shared skills and Unit 7; choose another science above to switch scope.
Qualification code: 60182362
Course details
Assessment Six 75-minute, 60-mark written exams, each worth 15%, plus Unit 7 Practical Assessment worth 10%; summer 2027 is the final full assessment, with a January 2028 resit subject to demand.
Tick a point after revising it. Progress is saved on this device and does not measure mastery.
Reviewed course guidance
Revision points, with the explanation beside them
Open a point to read what to know, how to use it in an assessment, a plain-language explanation and a self-check. Answers stay hidden until you choose to reveal them.
Options and source
Unit 1 tier
- Foundation
- Higher
Unit 2 tier
- Foundation
- Higher
Unit 3 tier
- Foundation
- Higher
Unit 4 tier
- Foundation
- Higher
Unit 5 tier
- Foundation
- Higher
Unit 6 tier
- Foundation
- Higher
Choose each applicable course selection before counting reviewed requirements.
There are no fully covered explanations for these selections yet. Partial support may still appear below. Use the official specification and your teacher’s guidance.
Progress could not be saved in this browser. Your ticks will remain for this page view only.
Topic group
Unit 1 · 1.1 · Cell Structure, Organization, and Basic Transport
- Core
Scope: Core · Topic 1.1 (core)
Open revision guidance
What to know
- Animal cells contain a cell membrane, cytoplasm, nucleus, and mitochondria.
- Plant cells contain all animal cell parts plus a cell wall, chloroplasts, and a large vacuole.
- The cell membrane controls entry/exit; the nucleus contains genetic information; mitochondria perform respiration; the cell wall provides support; chloroplasts perform photosynthesis; the vacuole stores cell sap.
- Cells differentiate to become specialised for specific functions (e.g., sperm cells, root hair cells).
- Levels of organization: Cells -> Tissues (groups of similar cells) -> Organs (groups of tissues) -> Organ Systems -> Organisms.
- Diffusion is the passive movement of particles down a concentration gradient through a membrane (e.g., O2 and CO2).
- Osmosis is the movement of water from high water concentration (low solute) to low water concentration (high solute) across a selectively permeable membrane.
- Visking tubing models living membranes; pores allow small molecules through but block large ones.
- Enzymes are proteins that act as biological catalysts to speed up chemical reactions.
- Temperature and pH affect enzyme activity; high temperatures (boiling) denature enzymes by destroying their active site shape.
What to do in an assessment
- Draw and label animal and plant cell diagrams.
- Use a light microscope to view cells using stains to identify structures.
- Explain the movement of substances in Visking tubing experiments based on particle size vs. membrane pore size.
- Interpret data graphs showing enzyme activity vs. temperature or pH.
In plain language
Cells are the building blocks of life, with plant cells having extra structures for support and food production. Cells work together as tissues and organs to keep organisms alive. Substances move into and out of cells via passive diffusion and osmosis. Enzymes are essential proteins that control life's chemical reactions, though they are very sensitive to changes in their environment like heat.
Self-check
Why does boiling an enzyme stop it from working?
Show the answer
Boiling denatures the enzyme, which means it permanently changes the shape of the enzyme, specifically its active site, so it can no longer bind with its substrate.
View diagrams
Plant cell · Unlabelled practice · Schematic, simplified and not to scale. Show labelled key: Answer key for plant-cell
Plant cell · Structure key · Schematic, simplified and not to scale. Animal cell · Unlabelled practice · Schematic, simplified and not to scale. Show labelled key: Answer key for animal-cell
Animal cell · Structure key · Schematic, simplified and not to scale. Compare the diagram with the explanation, then use practice mode before opening the key.
Topic group
Unit 1 · 1.1 · Advanced Enzyme Mechanisms and Active Transport
- Higher
Scope: Higher · Unit 1 tier: Higher · Topic 1.1 (higher)
Open revision guidance
What to know
- Active transport requires energy to move substances against a concentration gradient.
- Enzymes are composed of a chain of specific amino acids folded into a precise 3D shape.
- The 'lock and key' model describes how the substrate fits exactly into the enzyme's active site.
- Enzyme activity depends on molecular collisions. When the correct substrate hits an active site, an enzyme-substrate complex forms.
What to do in an assessment
- Diagram the enzyme-substrate complex formation.
- Contrast diffusion (passive, down gradient) with active transport (energy-requiring, against gradient).
In plain language
While simple movement is passive, cells also use energy to force substances against natural gradients. Enzymes work like locks and keys; the specific folding of their amino acid chain creates a unique active site where reactions occur when molecules collide with the right orientation.
Self-check
What is the result of an enzyme and substrate colliding correctly?
Show the answer
The formation of an enzyme-substrate complex.
Topic group
Unit 1 · 1.2 · Cellular Respiration and the Human Respiratory System
- Core
Scope: Core · Topic 1.2 (core)
Open revision guidance
What to know
- Aerobic respiration: Glucose + Oxygen -> Carbon dioxide + Water (releases energy)
- Anaerobic respiration (human cells): Glucose -> Lactic acid (releases energy, creates oxygen debt)
- Respiratory pathway: Nasal cavity, trachea, bronchi, bronchioles, alveoli, lungs, diaphragm, ribs, intercostal muscles
- Mechanics: Inspiration (diaphragm flattens, ribs move up/out, volume increases, pressure decreases), Expiration (diaphragm relaxes/domes, ribs move down/in, volume decreases, pressure increases)
- Gas Exchange: Alveoli are adapted with large surface area, moist lining, thin walls (one-cell thick), and rich capillary network
- Smoking: Damages cilia (causing mucus buildup), leads to lung cancer and emphysema
- Indicators: Lime water turns milky in the presence of carbon dioxide
What to do in an assessment
- Label diagram: nasal cavity, trachea, bronchi, bronchioles, alveoli, lungs, diaphragm, ribs, intercostal muscles
- Label alveolar cross-section: end of bronchiole, wall of alveolus, moist lining, capillary wall, red blood cells, plasma
- Compare inspired vs. expired air: Inspired (21% O2, 0.04% CO2), Expired (16% O2, 4% CO2)
- Evaluate bell jar model: Represents diaphragm/thoracic cavity/lungs but lacks rib elasticity and chest wall detail
In plain language
Respiration is how cells release energy. We inhale oxygen through our respiratory system, which uses a series of tubes (trachea, bronchi, bronchioles) to reach the alveoli, where oxygen enters the blood and carbon dioxide leaves. We control breathing by changing the size of our chest cavity using the diaphragm and ribs. Smoking damages the cleaning system of our lungs (cilia and mucus) and causes serious diseases like cancer and emphysema.
Self-check
Why does lime water turn milky when air is bubbled through it after exercise?
Show the answer
The air expired after exercise contains a higher concentration of carbon dioxide produced by respiration; carbon dioxide reacts with lime water to create a milky white precipitate.
Topic group
Unit 1 · 1.2 · Energetics of Respiration
- Higher
Scope: Higher · Unit 1 tier: Higher · Topic 1.2 (higher)
Open revision guidance
What to know
- ATP (Adenosine Triphosphate) acts as the chemical energy currency released during respiration
- Anaerobic respiration is significantly less efficient than aerobic because glucose is only partially broken down
- ATP Yield: Aerobic respiration produces a significantly higher quantity of ATP per glucose molecule compared to the incomplete breakdown occurring in anaerobic respiration
What to do in an assessment
- Compare efficiency: Define 'less efficient' by the ratio of energy extracted from one glucose molecule in aerobic versus anaerobic conditions
In plain language
While basic respiration provides energy, the higher level details explain that the energy is stored and moved in molecules called ATP. When oxygen is absent, our cells use a 'backup' anaerobic method; this is inefficient because it leaves most of the energy trapped in the lactic acid byproduct, resulting in a lower ATP yield than aerobic respiration.
Self-check
Compare the energy yield of aerobic versus anaerobic respiration.
Show the answer
Aerobic respiration produces more ATP per molecule of glucose because it fully breaks down the glucose, whereas anaerobic respiration is less efficient due to incomplete breakdown.
Topic group
Unit 1 · 1.3 · Human Digestive System and Nutrition
- Core
Scope: Core · Topic 1.3 (core)
Open revision guidance
What to know
- Digestion breaks down large insoluble molecules into smaller soluble ones for absorption by cells.
- Starch (carbohydrate) is a chain of glucose molecules. Proteins break down into amino acids. Fats break down into fatty acids and glycerol.
- Enzymes involved: Carbohydrases act on carbohydrates, proteases on proteins, lipases on fats.
- The digestive system: Mouth (initial mechanical/chemical digestion), Oesophagus (peristalsis), Stomach (acidic environment/protein digestion), Liver (bile production), Gall bladder (bile storage), Bile duct (transports bile), Pancreas (secretes enzymes), Small Intestine (absorption into blood), Large Intestine (water reabsorption), Anus (egestion).
- Peristalsis is the rhythmic contraction of muscles in the gut wall that pushes food forward.
- Bile emulsifies fats, breaking them into smaller droplets to increase surface area for lipase.
- Visking tubing acts as a model gut membrane, allowing small molecules like glucose to diffuse through while excluding large molecules like starch.
- Fate of products: Glucose provides energy or glycogen storage; amino acids are for protein synthesis; fatty acids/glycerol provide energy.
- Dietary needs: Protein, carbs, fats, iron, vitamin C, fibre, water. Excess energy intake is stored as body fat.
- Health implications: High intake of sugar, fat, and salt is associated with health issues.
What to do in an assessment
- Test for starch by adding iodine solution: colour change from yellow-brown to blue-black indicates presence.
- Test for glucose by heating with Benedict’s reagent: colour change from blue to green, yellow, or brick-red indicates presence.
- Test for protein by adding biuret solution: colour change from blue to purple indicates presence.
- Label a diagram of the digestive system: Mouth, Oesophagus, Stomach, Liver, Gall bladder, Bile duct, Pancreas, Small intestine, Large intestine, Anus.
- Describe the limitations of Visking tubing as a model: it lacks active transport, villi, and blood flow.
In plain language
Digestion turns the food you eat into tiny parts your body can use for energy and building tissue. We use special tests to find nutrients like starch, sugar, and protein in food, and organs like the stomach and intestines work together to break these down using enzymes. Bile helps process fats, and the gut moves food along using wave-like muscle contractions called peristalsis. Finally, the nutrients pass into the blood, while a balanced diet ensures we get the right minerals and vitamins to stay healthy.
Self-check
What is the role of bile in the digestion of fats?
Show the answer
Bile emulsifies fats by breaking them into smaller droplets, which increases their surface area for lipase enzymes to act upon.
Topic group
Unit 1 · 1.4 · The Human Circulatory System: Structure, Function, and Health
- Core
Scope: Core · Topic 1.4 (core)
Open revision guidance
What to know
- Red blood cells (biconcave discs) transport oxygen. Phagocytes (white blood cells with lobed nuclei) engulf pathogens.
- Blood components: Red cells (transport), platelets (clotting), plasma (transport of dissolved substances), white cells (immune defense).
- The heart is cardiac muscle that contracts to pump blood. Coronary arteries supply the heart muscle with oxygenated blood.
- Blood flows from the heart to organs via arteries and returns via veins.
- Heart structure: Right/left atria (collecting chambers), right/left ventricles (pumping chambers), tricuspid (right) and bicuspid (left) valves, semi-lunar valves (base of arteries), vena cava (deoxygenated entry), pulmonary artery (to lungs), pulmonary vein (from lungs), aorta (to body).
- Blood follows a double circulatory path: pulmonary (heart to lungs) and systemic (heart to body).
- Capillaries: One-cell-thick walls facilitate diffusion; extensive networks ensure every cell is proximal to blood supply.
- Cardiovascular disease risk factors: Smoking, high blood pressure, high cholesterol, lack of exercise, obesity.
What to do in an assessment
- Draw and label a biconcave red blood cell and a lobed-nucleus phagocyte.
- Sketch the heart: Label the four chambers, major vessels (aorta, vena cava, pulmonary artery/vein), and valves.
- Describe diffusion at the capillary bed: High concentration of oxygen in blood to low concentration in cells; CO2 from cells into blood.
- Explain backflow prevention: Valves close as ventricles contract, forcing blood only into arteries.
In plain language
The circulatory system acts as a high-speed transport network. The heart pumps blood through two loops: one to the lungs to pick up oxygen and another to deliver it to the whole body. Nutrients and oxygen reach your cells via tiny, thin-walled capillaries, while waste products are collected. Keeping this system healthy involves managing risk factors like diet and exercise to prevent cardiovascular disease.
Self-check
What is the primary function of the semi-lunar valves in the heart?
Show the answer
They prevent the backflow of blood from the pulmonary artery and aorta back into the ventricles after they have contracted.
Topic group
Unit 1 · 1.5 · Photosynthesis: The Foundation of Plant Life
- Core
Scope: Core · Topic 1.5 (core)
Open revision guidance
What to know
- Photosynthesis is the process where green plants and other photosynthetic organisms use chlorophyll to absorb light energy to convert carbon dioxide and water into glucose, releasing oxygen as a byproduct.
- The word equation for photosynthesis is: Carbon dioxide + Water (light energy/chlorophyll) -> Glucose + Oxygen.
- The rate of photosynthesis is affected by light intensity, temperature, and carbon dioxide concentration.
- Practical techniques include using sodium hydroxide (NaOH) to remove carbon dioxide from the air and testing leaves for starch using iodine solution.
- Glucose is used by plants for respiration, storage as starch, and synthesis of cellulose, proteins, and oils.
What to do in an assessment
- To test a leaf for starch: Boil the leaf in water to soften it, place it in boiling ethanol to remove chlorophyll, rinse in water, and add iodine solution. A blue-black colour indicates the presence of starch.
- To investigate carbon dioxide necessity: Enclose a plant in a container with sodium hydroxide; the plant will be unable to produce starch in its leaves due to the lack of CO2.
- Data logging: Use oxygen and carbon dioxide sensors to measure changes in gas concentration over time to determine the rate of photosynthesis.
In plain language
Photosynthesis is how plants make their own food. They use sunlight, trapped by the green pigment chlorophyll, to turn water and carbon dioxide from the air into glucose (sugar) and oxygen. This sugar is the plant's fuel, which it uses to grow, build structures like cell walls, or store for later as starch. We can measure how well this process is working by checking how much oxygen is produced or by checking if the plant is storing starch.
Self-check
What happens to a leaf if it is tested for starch after being kept in an atmosphere without carbon dioxide?
Show the answer
The leaf will test negative for starch (it will not turn blue-black with iodine) because carbon dioxide is a required raw material for the production of glucose, which is then converted into starch.
View diagrams
Dicot leaf section · Unlabelled practice · Schematic, simplified and not to scale. Show labelled key: Answer key for leaf-section
Dicot leaf section · Structure key · Schematic, simplified and not to scale. Compare the diagram with the explanation, then use practice mode before opening the key.
Topic group
Unit 1 · 1.5 · Supplement: Limiting Factors of Photosynthesis
- Higher
Scope: Higher · Unit 1 tier: Higher · Topic 1.5 (higher)
Open revision guidance
What to know
- A limiting factor is the environmental condition that is in shortest supply, thereby restricting the rate of photosynthesis at any given moment.
- Light intensity: As light intensity increases, the rate of photosynthesis increases until another factor becomes limiting.
- Carbon dioxide concentration: Increasing CO2 levels increases the rate of photosynthesis up to the point where light or temperature becomes the limiting factor.
- Temperature: Photosynthesis involves enzymes; therefore, the rate increases with temperature until an optimum point is reached, after which enzymes denature and the rate drops rapidly.
What to do in an assessment
- Analyse photosynthesis graphs: Identify the point of inflection where a curve flattens. This indicates that the current factor on the x-axis is no longer the limiting factor.
- Calculate rate of change: Use data logger outputs to plot oxygen production over time to identify how changes in light or CO2 intensity impact the rate.
In plain language
Even if a plant has everything it needs, the rate at which it makes food is held back by the one thing in shortest supply. If it's a cold morning, temperature is the limiting factor. If it's dark, light is the limiting factor. If the plant has plenty of light and heat but low CO2, then CO2 is the limiting factor. Understanding these limits helps in agriculture for optimising crop growth.
Self-check
If increasing the light intensity does not increase the rate of photosynthesis, what must be true?
Show the answer
Another factor, such as temperature or carbon dioxide concentration, must be acting as the limiting factor.
Topic group
Unit 1 · 1.6 · Energy Transfer and Environmental Impact in Ecosystems
- Core
Scope: Core · Topic 1.6 (core)
Open revision guidance
What to know
- Food chains show feeding relationships: producer (plant) -> primary consumer (herbivore) -> secondary consumer (carnivore) -> tertiary consumer (carnivore). Decomposers break down dead material.
- Energy is lost at each trophic level through respiration, waste (feces/urine), and growth repair.
- Pyramids of numbers count organisms; pyramids of biomass show the dry mass of organisms at each level.
- Intensive farming increases yield via fertilizers, pesticides, and battery housing, but can reduce biodiversity.
- Indicator species: Lichens (air pollution), bloodworms/sludge worms (stream pollution).
- Bioaccumulation: Heavy metals/pesticides accumulate in animal tissues, reaching toxic levels.
- Eutrophication: Sewage/fertilizer runoff triggers algal blooms; decomposition consumes dissolved oxygen, killing fish.
What to do in an assessment
- Draw a food web from a given list of organisms.
- Analyse a pyramid of biomass to explain why energy loss limits the number of trophic levels.
- Explain the stages of eutrophication: Nutrient enrichment -> algal bloom -> plants die -> microbial growth -> oxygen depletion.
In plain language
Energy flows through ecosystems starting from producers. Because organisms use most energy for living (respiration) and waste, only a fraction moves up the chain. Human farming affects this balance, and pollution like sewage or heavy metals can destroy aquatic habitats or build up to toxic levels in food chains.
Self-check
Why does the biomass decrease significantly as you move from producers to tertiary consumers in a food chain?
Show the answer
Energy is lost at each trophic level through respiration, excretion (waste), and the energy used for life processes/repair, meaning less energy is available to build new biomass for the next level.
View diagrams
Food web Food webHypothetical habitat · schematic, not to scaleTarget Organism Trophic role A ________________ ________________ B ________________ ________________ C ________________ ________________ D ________________ ________________ E ________________ ________________ F ________________ ________________ G ________________ ________________ Food → Consumer A B B C C D A E E F B G G D Show labelled key: Answer key for food-web
Food web Food webHypothetical habitat · schematic, not to scaleTarget Organism Trophic role A Grass Producer B Grasshopper Primary consumer C Frog Secondary consumer D Snake Tertiary consumer E Rabbit Primary consumer F Fox Secondary consumer G Bird Secondary consumer Food → Consumer Grass Grasshopper Grasshopper Frog Frog Snake Grass Rabbit Rabbit Fox Grasshopper Bird Bird Snake Compare the diagram with the explanation, then use practice mode before opening the key.
Topic group
Unit 1 · 1.6 · Efficiency of Energy Transfers
- Higher
Scope: Higher · Unit 1 tier: Higher · Topic 1.6 (higher)
Open revision guidance
What to know
- Energy transfer efficiency is the percentage of energy that passes from one trophic level to the next.
- Calculation formula: (Energy available at the next trophic level / Energy available at the previous trophic level) * 100.
What to do in an assessment
- Calculate efficiency: If a plant provides 10,000 kJ and the primary consumer stores 1,000 kJ as biomass, the efficiency is (1,000 / 10,000) * 100 = 10%.
In plain language
Higher tier mathematics allows us to quantify exactly how efficient an ecosystem is at moving energy between levels. Lower efficiency results in fewer organisms being supported at higher trophic levels.
Self-check
A herbivore consumes 5000 kJ of energy from a producer, but only 250 kJ is converted into new herbivore biomass. Calculate the efficiency.
Show the answer
(250 / 5000) * 100 = 5%.
Topic group
Unit 4 · 4.1 · Biodiversity, Classification, and Ecology
- Core
Scope: Core · Topic 4.1 (core)
Open revision guidance
What to know
- Living organisms vary in size, complexity, and features, broadly grouped into plants (flowering/non-flowering) and animals (vertebrates/invertebrates).
- Classification groups similar organisms to enable scientific identification, replacing ambiguous 'common' names with standardised scientific names.
- Morphological (body structure) and behavioural adaptations help organisms survive.
- Populations depend on limited resources (food, water, light, minerals); competition, predation, disease, and pollution limit population size.
- Biodiversity is the variety of species and their abundance in an area; its protection (via legislation) preserves ecosystem health.
- Quadrats are frames used for random sampling to estimate species abundance; sufficient data collection is essential for accuracy.
- Biological control involves using a predator or parasite to manage pests; alien species introduced to new areas can outcompete local species.
What to do in an assessment
- Use quadrats: Place a 0.25m² or 1m² frame randomly within a study area, count the individuals of a species, and repeat multiple times to calculate a mean.
- Extrapolate findings: Total Population = (Total Area / Quadrat Area) × Mean number per quadrat.
- Analyse case studies on the impact of invasive species like grey squirrels replacing red squirrels.
In plain language
This topic covers how we organise the millions of life forms on Earth, how they adapt to live in their environments, and the techniques we use to measure how many of them exist in an area.
Self-check
If you count an average of 5 daisies per 1m² quadrat in a 100m² field, what is the estimated total population?
Show the answer
500 daisies (5 per quadrat × 100 total square meters).
Topic group
Unit 4 · 4.1 · Population Estimation: Capture-Recapture
- Higher
Scope: Higher · Unit 4 tier: Higher · Topic 4.1 (higher)
Open revision guidance
What to know
- Capture-recapture is a method for estimating population size of mobile animals.
- Formula: Population Estimate = (Number marked in first sample × Number in second sample) / Number of marked animals found in second sample.
What to do in an assessment
- Capture a sample of animals (n1), mark them, and release them.
- Capture a second sample (n2) and record how many are marked (m).
- Calculate using the Lincoln-Peterson index: N = (n1 × n2) / m.
In plain language
When we cannot count every animal in a wild population, we mark a sample, release them, and then see what proportion of the second sample is marked to estimate the total population size.
Self-check
You catch 20 mice, mark them, and release them. Later, you catch 25 mice and 5 of them are marked. What is the estimated population?
Show the answer
100 mice (20 * 25) / 5 = 100.
Topic group
Unit 4 · 4.2 · Chromosomes, Cell Division, and Stem Cells
- Core
Scope: Core · Topic 4.2 (core)
Open revision guidance
What to know
- Chromosomes are linear arrangements of genes found in pairs in body cells.
- Mitosis results in two genetically identical diploid daughter cells, used for growth and repair.
- Meiosis results in four genetically distinct haploid gametes, used for sexual reproduction.
- Uncontrolled mitosis leads to the formation of tumors and cancer.
- Stem cells are undifferentiated cells capable of dividing to produce more stem cells or differentiating into specialised cell types.
- Embryonic stem cells have greater differentiation potential than adult stem cells, which are often restricted to specific tissue types.
What to do in an assessment
- Compare mitosis and meiosis based on number of divisions (one vs two), number of daughter cells (two vs four), and genetic content (diploid vs haploid).
- Describe the significance of stem cell therapy in replacing damaged tissues like nerve cells or muscle fibers.
- Analyse diagrams of the cell cycle to identify the stage of mitosis.
In plain language
In your body cells, DNA is organised into linear structures called chromosomes, which come in pairs. To replace worn-out cells or allow an organism to grow, cells divide via mitosis, creating clones. To create sex cells, meiosis reduces the chromosome number by half. If mitosis goes rogue, cancer occurs. We also have stem cells—special cells that haven't 'chosen' a job yet, allowing them to potentially repair damaged organs.
Self-check
What is the primary difference in the genetic makeup of the daughter cells produced by mitosis compared to meiosis?
Show the answer
Mitosis produces two genetically identical diploid daughter cells, whereas meiosis produces four genetically distinct haploid gametes.
Topic group
Unit 4 · 4.3 · DNA, Inheritance, and Genetic Engineering
- Core
Scope: Core · Topic 4.3 (core)
Open revision guidance
What to know
- DNA is two long chains of sugar and phosphate molecules connected by bases, twisted into a double helix.
- The four bases are A, T, C, and G.
- Base pairing is specific: A always pairs with T, and C always pairs with G.
- A gene is a section of DNA that determines inherited characteristics; alleles are different forms of these genes that exist in pairs.
- Genetic profiling involves cutting DNA into pieces and separating them into bands to compare samples for forensics, paternity, or species classification [L37, L47].
- Key terms: Gamete (sex cell), Chromosome (DNA structure), Genotype (genetic makeup), Phenotype (physical expression), Homozygous (identical alleles), Heterozygous (different alleles), Dominant, Recessive, F1/F2 generations, and selfing.
- Most phenotypic features arise from multiple genes.
- Sex determination: XX (female) and XY (male) chromosomes separate and combine randomly at fertilization.
- Genetic engineering is the artificial transfer of genes between organisms, offering various benefits and risks.
What to do in an assessment
- Construct Punnett squares for monohybrid crosses to predict genotype and phenotype ratios in offspring.
- Analyse a Punnett square where Bb (brown eyes) is crossed with Bb: offspring will be 25% BB, 50% Bb, 25% bb (a 3:1 phenotypic ratio of brown to blue eyes).
- Interpret banding patterns in genetic profiles to identify matches between DNA samples.
In plain language
DNA acts as a coded instruction manual for building proteins. By studying the order of bases and using tools like genetic profiling, we can understand heritage, solve crimes, and even modify genes to help society, though this technology brings both opportunities and ethical concerns.
Self-check
If a person is heterozygous (Bb) for a dominant trait, what are the possible genotypes of their gametes?
Show the answer
Their gametes will be either B or b.
Topic group
Unit 4 · 4.3 · Advanced DNA Structure and Protein Synthesis
- Higher
Scope: Higher · Unit 4 tier: Higher · Topic 4.3 (higher)
Open revision guidance
What to know
- The bases are specifically named: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
- The triplet code uses sequences of three bases to represent a single amino acid during protein synthesis.
- The specific order of these triplets along the DNA chain determines the exact sequence of amino acids linked together to build a functional protein.
What to do in an assessment
- Explain how the sequence of bases provides the blueprint for protein manufacturing via the triplet code.
- Translate hypothetical DNA sequences into amino acid strings using the triplet rule.
In plain language
The 'Higher' level focuses on the specific chemical names of the bases and the mechanics of the triplet code, which ensures that DNA provides precise instructions for protein building.
Self-check
How does the triplet code function during protein synthesis?
Show the answer
The triplet code consists of three sequential bases that specify which amino acid to add to a growing protein chain.
Topic group
Unit 4 · 4.4 · Variation, Inheritance, and Natural Selection
- Core
Scope: Core · Topic 4.4 (core)
Open revision guidance
What to know
- Variation in species arises from genetic and environmental factors.
- Sexual reproduction creates genetic diversity; asexual reproduction produces identical clones.
- Mutations are random changes in genes; most are neutral, some are harmful, others beneficial.
- Ionising radiation increases mutation rates.
- Cystic fibrosis is an inherited condition caused by mutation; gene therapy is a developing treatment.
- Evolution relies on heritable variation.
- Natural selection: better-adapted individuals survive and pass on successful genes.
- Environmental change can be too rapid for adaptation, leading to extinction.
- Ongoing evolution is seen in antibiotic and pesticide resistance.
- Human genome mapping is significant for medical advancement.
What to do in an assessment
- Contrast continuous variation (e.g., height) with discontinuous variation (e.g., blood type).
- Compare binary outcomes of sexual versus asexual reproduction.
- Analyse predator-prey camouflage models (e.g., dark vs. light moths on tree bark).
- Explain the mechanism of cystic fibrosis inheritance using Punnett squares.
- Describe the impact of human genome research on personalised medicine.
In plain language
Variation exists among individuals due to genes and environment. Sexual reproduction mixes genes, creating unique offspring, unlike clones. Mutations—random changes in DNA—fuel evolution. Individuals with helpful traits survive longer and breed more, passing these traits down (natural selection). Rapid environmental shifts can outpace this, causing extinction. We observe evolution today through antibiotic resistance and apply our knowledge of the human genome to create medical breakthroughs like gene therapy.
Self-check
If a bacterial population is exposed to antibiotics, why might the population become resistant over time?
Show the answer
Genetic mutations may create random variations in the bacterial population. Bacteria with resistance-conferring mutations survive the antibiotic treatment, breed, and pass the resistant genes to the next generation.
Topic group
Unit 4 · 4.4 · Tier: Continuous vs. Discontinuous Variation
- Higher
Scope: Higher · Unit 4 tier: Higher · Topic 4.4 (higher)
Open revision guidance
What to know
- Continuous variation is controlled by multiple genes (polygenic) and often influenced by the environment, producing a spectrum of phenotypes (e.g., height, skin colour).
- Discontinuous variation is usually controlled by a single gene or a few genes, resulting in distinct, non-overlapping categories (e.g., ABO blood groups, tongue rolling).
What to do in an assessment
- Plot a histogram for continuous data to show a normal distribution curve.
- Create a bar chart for discontinuous data to show distinct, separated categories.
In plain language
At the Higher level, you must distinguish between continuous and discontinuous variation. Continuous variation results in a range of values with no distinct groups, often appearing as a bell-shaped curve when graphed. Discontinuous variation produces clear, separate groups with no intermediates.
Self-check
Is human height an example of continuous or discontinuous variation, and why?
Show the answer
Continuous variation, because there is a wide range of values between the shortest and tallest individuals, and it is influenced by both polygenic inheritance and environmental factors like nutrition.
Topic group
Unit 4 · 4.5 · Nervous System, Homeostasis, and Regulation
- Core
Scope: Core · Topic 4.5 (core)
Open revision guidance
What to know
- Sense organs detect stimuli (light, sound, touch, temperature, chemicals) via receptor cells and transmit electrical impulses to the central nervous system (CNS).
- The CNS comprises the brain and spinal cord, linked by nerves.
- Reflex actions are fast, automatic, and protective (e.g., pupil size control).
- A reflex arc involves a stimulus, receptor, coordinator, effector, and synapses.
- Homeostasis maintains internal conditions to protect against harmful effects.
- Hormones are chemical messengers transported in the blood.
- Insulin (a protein) converts blood glucose into insoluble glycogen in the liver to lower glucose levels.
- Type 1 diabetes involves insufficient insulin production; Type 2 involves cells failing to respond to insulin.
- Skin structures: hair, erector muscle, sweat gland, sweat duct, sweat pore, and blood vessels.
- Temperature regulation: blood vessels change diameter (vasodilation/vasoconstriction), sweating, hair erection, and shivering generate or lose heat.
- Lifestyle impacts include alcohol/drug abuse affecting chemical processes and the link between lifestyle and Type 2 diabetes.
What to do in an assessment
- Diagram a reflex arc: Receptor -> Sensory Neurone -> Relay Neurone (in spinal cord) -> Motor Neurone -> Effector.
- Identify and label skin structures: hair, erector muscle, sweat gland, sweat duct, sweat pore, blood vessels.
In plain language
Your body has a complex internal communication network. The nervous system uses electrical signals for fast reactions called reflexes. Homeostasis keeps your internal body environment steady despite external changes. This is managed by hormones like insulin for blood sugar, and various skin mechanisms for body temperature. Your lifestyle, including diet and drug use, significantly influences these systems, particularly regarding conditions like Type 2 diabetes.
Self-check
What is the function of insulin when blood glucose levels rise?
Show the answer
Insulin is released by the pancreas into the blood and triggers the liver to convert glucose into insoluble glycogen for storage, thereby reducing blood glucose levels.
Topic group
Unit 4 · 4.5 · Concepts: Reflex Arcs and Negative Feedback
- Higher
Scope: Higher · Unit 4 tier: Higher · Topic 4.5 (higher)
Open revision guidance
What to know
- A reflex arc requires precise sequencing of components: stimulus detected by a receptor, transmitted by sensory neurones to a relay neurone in the spinal cord, then to a motor neurone, finally to an effector, bridged by synapses.
- Negative feedback is a control system where a change in a variable (like glucose levels or temperature) triggers a response that counteracts the change to return the system to an optimum point.
- In glucose control, insulin lowers blood glucose, while glucagon (a counter-regulatory hormone) raises it to maintain the homeostatic balance.
What to do in an assessment
- Construct a flow chart for a negative feedback loop: Stimulus -> Receptor -> Control Centre (Coordinator) -> Effector -> Response (reversing the stimulus).
- Explain how the combined actions of insulin and glucagon illustrate negative feedback by preventing extreme deviations in blood glucose.
In plain language
Higher-level understanding requires viewing body systems as self-regulating loops. A reflex arc is a specific, fixed pathway for automatic responses. Negative feedback is the overarching principle where the body monitors conditions, detects deviations from an 'ideal' level, and produces an opposite action to restore stability. For blood sugar, the interplay between two hormones—insulin to lower it and glucagon to raise it—ensures the level remains within a healthy range.
Self-check
How does negative feedback function in temperature control?
Show the answer
If body temperature rises above the optimum, receptors trigger cooling responses like sweating and blood vessel dilation. If it falls, shivering and hair erection occur to warm the body, maintaining equilibrium.
Topic group
Unit 4 · 4.6 · Pathogens, Immunity, and Disease Control
- Core
Scope: Core · Topic 4.6 (core)
Open revision guidance
What to know
- Most microorganisms are harmless and perform vital functions; pathogens are specific microorganisms that cause disease.
- Pathogens include bacteria (prokaryotic cells with DNA, cytoplasm, cell wall), viruses (genetic material in a protein coat), protists, and fungi.
- Communicable diseases spread via contact, aerosols, body fluids, contaminated water, insects, and food.
- Body defenses include skin barriers, blood clotting, phagocytes (engulf pathogens), and lymphocytes (produce antibodies/antitoxins).
- Antigens are molecules recognised by the immune system; foreign antigens trigger lymphocytes to produce specific antibodies that bind to them.
- Vaccination introduces modified antigens to stimulate an immune response. Factors affecting vaccination decisions include perceived risk versus benefits.
- Antibiotics (e.g., penicillin) are derived from organisms like fungi; they kill or inhibit bacteria but are ineffective against viruses.
- Antibiotic overuse causes antibiotic-resistant bacteria like MRSA; control requires hygiene and restricted use.
- Drug development requires rigorous, large-scale testing for efficacy and side effects, involving risk-benefit analysis and ethical considerations regarding animal testing.
What to do in an assessment
- Define 'pathogen' and list the four main types.
- Describe the mechanism of blood clotting and phagocytosis.
- Explain the interaction between a specific antibody and its target antigen.
- Evaluate the risks, benefits, and ethics of animal testing in drug trials.
In plain language
Most germs are helpful, but some (pathogens) make us sick. Our bodies fight these using physical barriers like skin, clots, and specialised white blood cells that 'eat' germs or create 'keys' (antibodies) to lock onto specific invaders. Medicines called antibiotics kill bacteria but don't work on viruses. Because of overuse, some bacteria have become resistant to antibiotics. New drugs undergo strict testing to ensure they are safe before they are used on people.
Self-check
Why are antibiotics ineffective against viruses?
Show the answer
Antibiotics target mechanisms specific to bacterial survival, such as cell wall synthesis or bacterial protein synthesis, which viruses do not possess as they hijack host cell machinery.
Topic group
Unit 4 · 4.6 · Vaccination and Immunological Memory
- Higher
Scope: Higher · Unit 4 tier: Higher · Topic 4.6 (higher)
Open revision guidance
What to know
- Vaccines contain antigens derived from specific disease-causing organisms to stimulate an immune response without causing the full disease.
- Vaccines can be engineered to protect against both bacteria and viruses.
- Upon initial antigen exposure, memory cells are formed. If the same antigen enters the body again, memory cells trigger a rapid, massive production of specific antibodies.
- This immunological memory provides long-term immunity following both natural infection and vaccination.
- The immune response is highly specific: a particular antibody or memory cell is designed for exactly one type of antigen.
What to do in an assessment
- Compare the primary immune response to the secondary response after re-exposure to an antigen.
- Explain how memory cells provide immunity.
In plain language
Vaccines teach your immune system how to recognise a pathogen by showing it the pathogen's 'ID tag' (antigen). This creates 'memory cells.' If you are exposed to the real germ later, these memory cells remember the antigen and start making huge amounts of the correct antibody immediately, stopping the disease before you notice symptoms.
Self-check
How do memory cells improve the immune response during a second infection?
Show the answer
Memory cells persist after the initial infection or vaccination; upon re-exposure, they rapidly produce specific antibodies much faster and in greater quantities than the initial response, preventing illness.
Topic group
Skills across the sciences
- Core
Scope: Core · shared-enquiry; core
Open revision guidance
What to know
- Develop hypotheses and devise procedures [L125]
- Select appropriate apparatus and techniques [L125]
- Use SI units, prefixes, and powers of ten [L136]
- Understand random and systematic errors [L136]
- Data quality: accuracy, precision, repeatability, and reproducibility [L136]
- Risk evaluation and ethical considerations [L125]
What to do in an assessment
- Plan investigations to ensure samples are representative [L125]
- Collect/record data accurately including uncertainty estimation [L125, L136]
- Present data via tables, graphs, and symbolic forms [L136]
- Translate data between forms and identify patterns/trends [L136]
- Evaluate methods to suggest improvements [L125]
In plain language
Scientific enquiry involves planning experiments, selecting equipment, and collecting data with awareness of errors. You must ensure results are repeatable and reproducible, use proper SI units, and evaluate your findings to draw conclusions based on evidence.
Self-check
What is the difference between repeatability and reproducibility?
Show the answer
Repeatability is achieving the same results using the same methods/equipment by the same investigator, while reproducibility involves different conditions or investigators reaching similar findings.
- Core
Scope: Core · shared-maths; core
Open revision guidance
What to know
- Arithmetic: decimal form, standard form, ratios, fractions, percentages [L158]
- Handling data: significant figures, arithmetic means, tables/diagrams [L158]
- Probability: understanding simple probability [L158]
- Algebra: substitute numerical values and solve equations, change the subject [L158]
- Graphs: y=mx+c linear relationship, plotting variables, interpret slope and intercept [L158]
- Geometry: angular measures, area of triangles/rectangles, surface area/volume [L158]
What to do in an assessment
- Convert between units (e.g., km to m, g to kg) [L136]
- Perform order of magnitude calculations [L158]
- Calculate area of a rectangle (base x height) or volume of a cube (side³) [L158]
- Determine the gradient (m) and y-intercept (c) from a linear graph [L158]
- Solve for variables in physical formulae [L158]
In plain language
Mathematical skills are essential for science. You must be able to handle arithmetic, work with significant figures and units, use algebra to manipulate formulae, and construct/interpret linear graphs and geometric shapes.
Self-check
If y = 3x + 2, what is the gradient and the y-intercept?
Show the answer
The gradient (m) is 3 and the y-intercept (c) is 2.
- Higher
Scope: Higher · Higher in either Unit 1 tier or Unit 2 tier or Unit 3 tier or Unit 4 tier or Unit 5 tier or Unit 6 tier · shared-maths; higher
Open revision guidance
What to know
- Tangents: Using the gradient of a tangent to determine instantaneous rate of change [L158]
- Area under curves: Physical significance of area between a curve and the x-axis [L158]
What to do in an assessment
- Draw a tangent to a curve at a point and calculate gradient (dy/dx ≈ rise/run) [L158]
- Estimate area under a curve by counting squares [L158]
In plain language
Higher tier maths requires interpreting curved graphs. You must find the rate of change by drawing a tangent and calculating its gradient, and estimate physical quantities (like displacement) by counting squares under a curve.
Self-check
How do you find the instantaneous rate of change from a curved graph?
Show the answer
Draw a tangent to the curve at the specific point and calculate the gradient (slope) of that straight line.
Topic group
Unit 7 Practical Assessment Guidance
- Core
Scope: Core · unit-7; core
Reading this guidance does not complete practical assessment. It is not counted as written-exam progress.
Open revision guidance
What to know
- Assessment structure: Two tasks chosen by the centre (Biology/Chemistry/Physics) [L114]
- Section A: Obtaining results, 60 minutes, group work allowed (max 3), 6 marks [L114]
- Section B: Analysis and evaluation, 60 minutes, individual work, 24 marks [L114]
What to do in an assessment
- Perform experiments to obtain results in Section A [L114]
- Analyze/evaluate data and answer questions individually in Section B [L114]
- Ensure all data presented follows scientific notation and significant figure rules [L136]
In plain language
Unit 7 is an externally marked practical assessment worth 10% of your grade. You collect data in groups for Section A, then analyse that data individually under formal exam conditions in Section B.
Self-check
Are you allowed to receive teacher help during Section B?
Show the answer
No, Section B is conducted under high control with no teacher feedback or assistance allowed.
Topic group
Unit 1 · practical:1.1 · Microscopy and Enzyme Investigation
- Core
Scope: Core · Topic practical:1.1 (core)
Open revision guidance
What to know
- Light microscopes use lenses to magnify specimens; total magnification equals eyepiece lens power multiplied by objective lens power.
- Enzyme activity is affected by factors like pH and temperature.
- Scientific diagrams require continuous, single-line outlines without shading, and clear labels using straight lines.
What to do in an assessment
- To view cells: Prepare a slide by placing a thin tissue section on a slide, adding a drop of stain, and covering with a coverslip.
- Use the microscope, starting with the lowest power objective lens, to bring the specimen into focus.
- Draw observed cells using a sharp pencil, including scale bars or magnification notation.
- To investigate enzymes: Prepare water baths at set temperatures (e.g., 20C, 40C, 60C).
- Mix a fixed volume of enzyme solution with a fixed volume of substrate in a test tube.
- Use a stopwatch to measure the time taken for a specific change (e.g., disappearance of starch indicated by iodine testing) and calculate the rate as 1/time.
- Maintain control variables: keep volume and concentration of enzyme and substrate constant.
In plain language
This lesson covers how to look at tiny cells under a microscope and how to test how different conditions change how fast enzymes work. Remember that completing this lesson does not replace the requirement to perform the practicals under school supervision.
Self-check
If an enzyme reaction takes 50 seconds to complete, what is the rate of reaction?
Show the answer
The rate is 1/50 = 0.02 per second.
Topic group
Unit 1 · practical:1.3 · Investigation of the energy content of foods
- Core
Scope: Core · Topic practical:1.3 (core)
Open revision guidance
What to know
- Energy is released from food when it burns.
- The energy can be transferred to a known volume of water to estimate the food's energy content.
- Specific heat capacity of water (4.18 J/g°C) is required to calculate energy.
- Sources of error include heat loss to the surroundings and incomplete combustion.
What to do in an assessment
- Measure 20cm³ of cold water and place it into a boiling tube held by a clamp stand.
- Measure and record the initial temperature of the water.
- Weigh a small piece of food and record the mass.
- Set fire to the food using a Bunsen burner, then immediately hold it underneath the boiling tube.
- Keep the food burning under the tube until it will no longer light, then record the final water temperature.
- Calculate the temperature change (ΔT) and use the formula: Energy (J) = mass of water (g) × 4.18 × ΔT.
- Calculate energy per gram of food by dividing total energy by the mass of the food piece.
In plain language
This experiment estimates how much chemical energy is stored in food by burning it to heat up water. Because heat escapes into the air rather than entering the water, this method will always underestimate the total energy present in the food.
Self-check
If 1g of food heats 20g of water by 10°C, how much energy is released per gram of food?
Show the answer
Energy = 20g × 4.18 J/g°C × 10°C = 836 Joules per gram.
Topic group
Unit 1 · practical:1.5 · Investigation of the factors affecting photosynthesis
- Core
Scope: Core · Topic practical:1.5 (core)
Open revision guidance
What to know
- Photosynthesis rate is influenced by light intensity, temperature, and carbon dioxide concentration.
- The rate is measured by counting oxygen bubbles produced by an aquatic plant like pondweed (Cabomba or Elodea) over a set time.
- Light intensity follows the inverse square law: as distance from a light source increases, light intensity decreases proportionally to 1/d squared.
- A heat shield (beaker of water) is necessary to prevent temperature from becoming a confounding variable.
What to do in an assessment
- Place a boiling tube containing an aquatic plant in a sodium hydrogen carbonate solution (providing CO2) at a set distance from an LED light source.
- Allow the plant to acclimatize for 5 minutes.
- Count the number of oxygen bubbles released from the cut stem over a 3-minute period.
- Repeat this measurement at varying distances (e.g., 10cm, 20cm, 30cm, 40cm, 50cm).
- Record results in a table and calculate the rate of photosynthesis by dividing the total bubbles by the time elapsed.
- Maintain temperature stability by ensuring a beaker of water is placed between the lamp and the plant to act as a heat sink.
In plain language
We measure how fast a water plant performs photosynthesis by counting how many bubbles of oxygen it releases. By moving a lamp further away, we decrease the light intensity to see how it slows down the rate of bubble production. Keeping the room temperature consistent and using a water shield ensures that light is the only factor changing.
Self-check
If you move the lamp from 10cm to 20cm, what happens to the light intensity?
Show the answer
The light intensity becomes one-fourth of the original intensity because light intensity is proportional to 1/distance squared.
Topic group
Unit 4 · practical:4.1 · Investigating Species Distribution and Abundance
- Core
Scope: Core · Topic practical:4.1 (core)
Open revision guidance
What to know
- Quadrats are square frames used to sample a defined area.
- Transects are lines used to study changes in distribution across a gradient.
- Random sampling reduces bias when measuring abundance.
- Systematic sampling along a transect identifies changes relative to environmental factors.
What to do in an assessment
- Use a random number generator to select coordinates within a study site.
- Place a 0.5m x 0.5m quadrat at the selected coordinates.
- Count the individuals of the target species within the quadrat frame.
- Calculate the mean number of organisms per quadrat.
- Estimate total population using: (Total area / Area of quadrat) x Mean number per quadrat.
- Lay a tape measure (transect) across the site and place quadrats at regular intervals to observe distribution shifts.
- Wear appropriate footwear and supervise to avoid contact with stinging or toxic plants.
In plain language
This practical helps you estimate how many organisms are in an area and how their distribution changes based on environmental conditions. By using quadrats to sample random spots or a line transect to check specific paths, you can gather data to draw conclusions about ecosystem health.
Self-check
If you find 5 daisies in a 0.25m² quadrat, and the field is 100m², what is the estimated population?
Show the answer
Divide the field area (100) by the quadrat area (0.25) to get 400. Multiply 400 by the mean count (5) to get an estimated population of 2000 daisies.
Topic group
Unit 4 · practical:4.4 · Investigation into variation in organisms
- Core
Scope: Core · Topic practical:4.4 (core)
Open revision guidance
What to know
- Variation is the differences between individuals of the same species.
- Continuous variation shows a range of values (e.g., height, leaf length).
- Discontinuous variation falls into distinct categories (e.g., blood type, eye colour).
- Sample size affects the reliability of the data representation.
What to do in an assessment
- Select a population of organisms, such as 50 leaves from the same tree species.
- Choose a continuous characteristic to measure, such as the length of the leaf blade in millimeters.
- Use a ruler to measure each leaf consistently from the base of the blade to the tip.
- Record results in a tally chart to create frequency groups (e.g., 50-55mm, 56-60mm).
- Ensure supervision is present when using sharp tools for sample collection.
- Wear gloves if collecting samples from unknown plants to avoid skin irritation.
- Calculate the mean by summing all measurements and dividing by the number of samples.
- Plot a histogram to display the frequency distribution of the continuous variable.
In plain language
This practical helps you understand how physical traits vary across a group of the same species. By measuring a specific feature—like leaf size—on many individuals, you can see how most individuals cluster around an average while some are smaller or larger, forming a pattern of variation.
Self-check
If you measured 20 leaves and found a mean length of 60mm, but your friend measured 100 leaves and found a mean of 65mm, whose data is likely more representative of the tree population?
Show the answer
The friend's data is likely more representative because a larger sample size reduces the impact of individual anomalies and provides a more accurate reflection of the population's true variation.
Topic group
Unit 4 · practical:4.5 · Investigation into factors affecting reaction time
- Core
Scope: Core · Topic practical:4.5 (core)
Open revision guidance
What to know
- Reaction time is the time taken to respond to a stimulus.
- Common factors affecting reaction time include distractions, fatigue, and the effect of caffeine.
- A ruler drop test is a standard method to measure human reaction time.
What to do in an assessment
- Sit on a chair and place your forearm on the table with your hand overhanging the edge.
- Have a partner hold a 30 cm ruler vertically so the zero mark is level with the top of your thumb.
- Without warning, your partner drops the ruler.
- Catch the ruler as quickly as possible between your thumb and index finger.
- Record the measurement on the ruler level with the top of your thumb.
- Repeat the test 10 times to calculate a mean reaction time.
- Use a conversion table to change the distance caught (cm) into reaction time (s).
- Test the effect of a specific factor, such as consuming a caffeinated drink, by repeating the experiment after a set time.
In plain language
This practical measures how quickly your brain processes information and triggers a muscle response. By dropping a ruler and seeing how far it falls before you catch it, you can estimate your reaction time. Comparing this across different conditions, like after resting or having a coffee, shows how external factors influence your response speed.
Self-check
If a student catches a ruler at 15 cm, how does this compare to catching it at 5 cm in terms of reaction speed?
Show the answer
Catching it at 15 cm indicates a slower reaction time than catching it at 5 cm, because the ruler had more time to fall due to gravity before being caught.
How OmniStudy helps you revise
- Answer exam-style questions on any topic below and get marked in seconds, with feedback on how to win more marks.
- Flashcards, quizzes and revision games generated for every topic.
- Practise real past papers with mark schemes.
- A study planner with an exam countdown, built around your weakest topics.
- Everything works in English and Welsh.
This guide is also available in Welsh (Cymraeg): Welsh (Cymraeg) guide
Ready to start?
Free to start. Pick your subject, answer a question, and see your first mark in minutes.
Start revising free