Biology — Original Practice
(a) Name the cell structure that controls the activities of a cell. (1)
(b) State two structures found in a plant cell but not in a typical animal cell. (2)
(c) Explain the function of the cell membrane. (1)
Show answer and marking guidance
(a) Nucleus. (1)
(b) Any two: cell wall, chloroplast, large permanent vacuole. (1 each)
(c) Controls movement of substances into and out of the cell; it is selectively permeable. (1)
A student investigates the effect of temperature on an enzyme. Explain why the rate of enzyme activity increases as temperature rises towards the optimum, and why it decreases rapidly above the optimum.
Show answer and marking guidance
As temperature rises, particles gain kinetic energy and collide more frequently, so more enzyme-substrate complexes form. Above the optimum, bonds maintaining the enzyme's shape are disrupted; the active site changes shape (denaturation), so the substrate is less complementary and fewer complexes form. Award up to 5 marks for these linked points.
(a) Write the word equation for photosynthesis. (2)
(b) State two factors that can limit the rate of photosynthesis. (2)
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(a) Carbon dioxide + water → glucose + oxygen, in the presence of light and chlorophyll. (2)
(b) Any two: light intensity, carbon dioxide concentration, temperature, chlorophyll availability. (1 each)
Chemistry — Original Practice
An atom has proton number 17 and nucleon number 35. Determine its number of (a) protons, (b) neutrons and (c) electrons, assuming the atom is neutral.
Show answer and marking guidance
(a) 17 protons. (1)
(b) 35 − 17 = 18 neutrons. (1)
(c) 17 electrons because a neutral atom has equal numbers of protons and electrons. (2)
Explain why sodium chloride has a high melting point and why it conducts electricity when molten but not when solid.
Show answer and marking guidance
It has a giant ionic lattice (1) with strong electrostatic attractions between oppositely charged ions (1), requiring much energy to overcome. When molten, ions are mobile and carry charge (1); in the solid lattice, ions are fixed in position and cannot move (1).
Hydrochloric acid reacts with sodium hydroxide. (a) Name the type of reaction. (1) (b) Write the balanced symbol equation. (2) (c) Name the salt formed. (1)
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(a) Neutralisation. (1)
(b) HCl + NaOH → NaCl + H₂O. (2)
(c) Sodium chloride. (1)
Physics — Original Practice
A car increases its velocity uniformly from 5 m/s to 25 m/s in 4 seconds. Calculate its acceleration and state the equation used.
Show answer and marking guidance
Acceleration = change in velocity ÷ time (1). a = (25 − 5) ÷ 4 (1) = 5 m/s² (2).
A 6 Ω resistor is connected to a 12 V supply. Calculate the current through the resistor and the electrical power dissipated.
Show answer and marking guidance
Using V = IR: I = 12 ÷ 6 = 2 A (2). Power P = VI = 12 × 2 = 24 W (2).
A metal block has a mass of 540 g and a volume of 200 cm³. Calculate its density in g/cm³.
Show answer and marking guidance
Density = mass ÷ volume (1) = 540 ÷ 200 (1) = 2.7 g/cm³ (1).
Mathematics — Original Practice
Solve the equation 3(2x − 1) = 4x + 9. Show your working.
Show answer and marking guidance
6x − 3 = 4x + 9 (1); 2x = 12 (1); x = 6 (1).
A laptop costs KSh 48,000. Its price is reduced by 15%. Calculate the sale price.
Show answer and marking guidance
Discount = 0.15 × 48,000 = KSh 7,200 (2). Sale price = 48,000 − 7,200 = KSh 40,800 (1).
A right-angled triangle has perpendicular sides of 6 cm and 8 cm. Calculate the length of the hypotenuse.
Show answer and marking guidance
c² = 6² + 8² (1) = 36 + 64 = 100 (1), so c = 10 cm (1).
Expanded Syllabus-Mapped Practice Bank
Exam standard: Original questions designed around syllabus objectives, precise command words, realistic contexts, multi-step reasoning and mark-based answers. These are practice materials, not official Cambridge questions.
How to use: Attempt each question without opening its answer. Show working in calculations. Award marks only for the stated scientific or mathematical points. Teachers should adapt Core/Extended depth to the learner's registered syllabus route.
Biology — 0610 · 21 syllabus areas
A microorganism has no nucleus and its genetic material is free in the cytoplasm. Identify its cell type and give one other characteristic.
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It is a prokaryote. It has no membrane-bound organelles / has a cell wall made of peptidoglycan / is generally smaller than eukaryotic cells. [2]
Arrange these levels of organisation from simplest to most complex: organ, cell, organ system, tissue. Define a tissue.
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Cell → tissue → organ → organ system. A tissue is a group of similar cells working together to perform a particular function. [2]
A plant cell is placed in a concentrated sucrose solution. Describe the net movement of water and explain the resulting change to the cell.
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Water moves out by osmosis, from higher water potential inside to lower water potential outside, through the partially permeable cell membrane. The vacuole/cytoplasm shrinks and the membrane pulls away from the cell wall (plasmolysis). [3]
A food sample turns blue-black when iodine solution is added. Identify the nutrient and describe one biological role of it.
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Starch. It is a carbohydrate used as an energy store in plants; it can be hydrolysed to glucose for respiration. [2]
Explain why an enzyme-catalysed reaction may stop when the substrate concentration is increased no further but enzyme concentration remains constant.
Show worked answer and marking guidance
At sufficiently high substrate concentration, all enzyme active sites are occupied; enzyme concentration becomes the limiting factor and the rate reaches a maximum. [2]
A plant is kept in darkness for 48 hours and then one leaf is partly covered before exposure to light. Describe the test and expected result for starch.
Show worked answer and marking guidance
Boil leaf in water, heat in ethanol in a water bath to remove chlorophyll, rinse, then add iodine. Exposed regions turn blue-black; covered region remains yellow-brown, showing light is needed for starch production. [3]
Explain how the structure of a small-intestine villus is adapted for absorption.
Show worked answer and marking guidance
Large surface area from villi/microvilli; epithelium one cell thick for short diffusion distance; rich capillary network maintains concentration gradient; lacteal absorbs fatty acids/glycerol. [3]
Explain how a high rate of transpiration can increase the movement of water from roots to leaves.
Show worked answer and marking guidance
Evaporation from mesophyll and diffusion of water vapour out through stomata lowers water potential in leaves, creating tension in xylem; cohesion between water molecules maintains a continuous column pulled upwards. [3]
State two differences between arteries and veins and explain how each difference relates to its function.
Show worked answer and marking guidance
Arteries have thicker muscular/elastic walls to withstand high pressure; narrower lumen helps maintain pressure. Veins have a wider lumen and valves to reduce resistance/prevent backflow at low pressure. [3]
Explain how vaccination can reduce the spread of an infectious disease in a population.
Show worked answer and marking guidance
A harmless form/antigen stimulates lymphocytes to produce specific antibodies and memory cells. On later exposure, memory cells produce antibodies rapidly, reducing infection/transmission; high coverage reduces susceptible hosts. [3]
Explain why the alveoli are efficient gas-exchange surfaces.
Show worked answer and marking guidance
Many alveoli provide large surface area; walls are one cell thick; moist lining allows gases to dissolve; dense capillary supply and ventilation maintain steep concentration gradients. [3]
Compare aerobic respiration with anaerobic respiration in human muscle cells during vigorous exercise.
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Aerobic respiration uses oxygen and completely breaks down glucose to carbon dioxide and water, releasing much energy. Anaerobic respiration occurs without oxygen, produces lactic acid and releases less energy. [3]
Describe how the kidney helps maintain water balance when a person is dehydrated.
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More ADH is released; collecting ducts become more permeable to water; more water is reabsorbed into blood; a smaller volume of concentrated urine is produced. [3]
A person touches a hot surface and withdraws their hand. Outline the reflex arc.
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Receptor detects stimulus; sensory neurone carries impulse to CNS; relay neurone connects to motor neurone; motor neurone carries impulse to effector muscle; muscle contracts and withdraws hand. [4]
Explain one harmful effect of smoking on gas exchange and one effect on the circulatory system.
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Tar damages/cilia and alveolar walls, reducing surface area and gas exchange; carbon monoxide binds to haemoglobin, reducing oxygen transport; nicotine increases heart rate/blood pressure. [2]
Explain the roles of the placenta and umbilical cord during human pregnancy.
Show worked answer and marking guidance
Placenta allows exchange of oxygen/nutrients from maternal blood to fetal blood and carbon dioxide/urea in the opposite direction without normally mixing the blood; umbilical vein carries oxygenated blood to fetus and arteries return deoxygenated blood. [3]
In a cross between two heterozygous parents (Aa × Aa), determine the probability of offspring showing the recessive phenotype.
Show worked answer and marking guidance
Genotypes: AA, Aa, Aa, aa. Only aa shows recessive phenotype, so probability is 1/4 or 25%. [2]
A population of insects contains individuals with different resistance to an insecticide. Explain how repeated insecticide use can increase the frequency of resistance.
Show worked answer and marking guidance
Some insects have inherited resistance due to genetic variation; insecticide kills more non-resistant insects; resistant individuals survive and reproduce, passing alleles to offspring; resistance allele frequency rises over generations. [3]
Explain how energy is transferred and lost along a food chain, and why food chains are usually short.
Show worked answer and marking guidance
Energy passes in biomass between trophic levels. Energy is lost through respiration/heat, movement, waste and uneaten material; less energy is available at each level, limiting chain length. [3]
Describe two ways deforestation can affect ecosystems and the carbon cycle.
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Habitat loss reduces biodiversity; soil erosion increases; fewer trees remove carbon dioxide by photosynthesis, while burning/decay releases carbon dioxide, increasing atmospheric concentration. [3]
Outline the main stages used to transfer a useful human gene into bacteria to produce a protein.
Show worked answer and marking guidance
Identify and isolate the gene; cut gene and bacterial plasmid with the same restriction enzyme; join using DNA ligase; insert recombinant plasmid into bacteria; select transformed bacteria and culture them to express the gene. [4]
Chemistry — 0620 · 12 syllabus areas
Use particle theory to explain why a gas can be compressed much more easily than a liquid.
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Gas particles are far apart with large spaces between them, so they can be forced closer together. Liquid particles are already close-packed with little empty space. [2]
An ion has 13 protons and 10 electrons. State its charge and explain your answer.
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3+; it has three more protons than electrons, giving a net positive charge of three. [2]
Calculate the relative formula mass of Ca(OH)₂. (Ar: Ca=40, O=16, H=1).
Show worked answer and marking guidance
Mr = 40 + 2(16 + 1) = 40 + 34 = 74. [2]
During electrolysis of molten lead(II) bromide, name the product at each electrode and explain how it forms.
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Cathode: lead; Pb²⁺ gains two electrons (reduction). Anode: bromine; Br⁻ loses electrons (oxidation), forming Br₂. [3]
A reaction mixture becomes colder during a reaction. State whether the reaction is endothermic or exothermic and explain the energy transfer.
Show worked answer and marking guidance
Endothermic; the reaction takes in energy from the surroundings, so the surroundings/mixture temperature falls. [2]
Explain how increasing temperature usually increases the rate of a reaction between particles.
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Particles have greater kinetic energy; collisions occur more frequently and a greater proportion have energy equal to or above activation energy, so more successful collisions occur per second. [3]
Describe how to prepare pure, dry crystals of copper(II) sulfate from dilute sulfuric acid and excess copper(II) oxide.
Show worked answer and marking guidance
Warm acid; add copper(II) oxide until in excess; filter off unreacted solid; heat filtrate to concentrate; cool to crystallise; filter and dry crystals. [4]
Explain why elements in the same group of the Periodic Table have similar chemical properties.
Show worked answer and marking guidance
They have the same number of electrons in their outer shell, so they have similar tendencies to lose, gain or share electrons and form similar ions/bonds. [2]
Explain why aluminium is extracted by electrolysis rather than by reduction with carbon.
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Aluminium is more reactive than carbon and its oxide is too stable to be reduced by carbon; electrolysis is used to remove oxygen from molten aluminium oxide. [2]
Explain how sulfur dioxide released from burning fossil fuels can damage the environment.
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It dissolves in rainwater and forms acidic solutions, contributing to acid rain; this acidifies lakes/soils, harms aquatic organisms and damages vegetation/buildings. [2]
Describe the test that distinguishes an alkene from an alkane using bromine water.
Show worked answer and marking guidance
Shake each sample with bromine water. An alkene decolourises orange/brown bromine water to colourless by addition across the C=C bond; an alkane shows no change in these conditions. [2]
A student is given a mixture of sand and sodium chloride. Describe how to obtain dry sodium chloride from the mixture.
Show worked answer and marking guidance
Add water to dissolve sodium chloride; filter to remove insoluble sand; evaporate some water; allow solution to crystallise; filter and dry crystals. [3]
Physics — 0625 · 6 syllabus areas
A 1200 kg car accelerates from rest to 20 m/s in 10 s. Calculate its acceleration and resultant force.
Show worked answer and marking guidance
a = (20−0)/10 = 2 m/s². F = ma = 1200 × 2 = 2400 N. [3]
Explain, using particle ideas, why a metal spoon becomes hot along its length when one end is placed in hot water.
Show worked answer and marking guidance
At the hot end, particles gain energy and free electrons transfer energy rapidly through the metal; collisions transfer energy to cooler regions, so thermal energy conducts along the spoon. [3]
A wave has frequency 50 Hz and wavelength 0.8 m. Calculate its speed and state the equation.
Show worked answer and marking guidance
v = fλ = 50 × 0.8 = 40 m/s. [2]
Two resistors of 3 Ω and 6 Ω are connected in parallel across a 12 V supply. Calculate the current in each branch and the total current.
Show worked answer and marking guidance
Each branch has 12 V. I₁=12/3=4 A; I₂=12/6=2 A; total current = 4+2 = 6 A. [3]
A radioactive source has a half-life of 6 hours. Its activity is initially 800 counts/min. Calculate its activity after 18 hours.
Show worked answer and marking guidance
18 hours is three half-lives: 800 → 400 → 200 → 100 counts/min. [2]
Explain why planets remain in orbit around the Sun rather than travelling in a straight line.
Show worked answer and marking guidance
The Sun's gravitational force provides the centripetal force, continually changing the direction of each planet's velocity and keeping it in orbit. [2]
Mathematics — 0580 · 9 syllabus areas
A jacket is reduced by 12% to KSh 4,400. Calculate its original price.
Show worked answer and marking guidance
4,400 represents 88%. Original price = 4400 ÷ 0.88 = KSh 5,000. [2]
Solve simultaneously: 2x + y = 11 and x − y = 1.
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Add equations: 3x=12, so x=4. Substitute: 4−y=1, so y=3. [3]
Find the gradient of the line through points (2, 3) and (6, 11).
Show worked answer and marking guidance
Gradient = (11−3)/(6−2) = 8/4 = 2. [2]
The interior angles of a quadrilateral are x, 2x, 3x and 4x. Find the largest angle.
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x+2x+3x+4x=360°, so 10x=360°, x=36°. Largest angle = 4x = 144°. [3]
A cylinder has radius 3 cm and height 10 cm. Calculate its volume in terms of π.
Show worked answer and marking guidance
V=πr²h=π×3²×10=90π cm³. [2]
A right-angled triangle has hypotenuse 13 cm and an angle of 30°. Calculate the side opposite the angle.
Show worked answer and marking guidance
sin 30° = opposite/13; opposite = 13 × 0.5 = 6.5 cm. [2]
Point P(−2, 5) is translated by vector (4, −3). Find its image P′.
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Add components: (−2+4, 5−3) = (2, 2). [2]
A bag contains 5 red, 3 blue and 2 green counters. One counter is selected at random. Find the probability it is not blue.
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Not blue = 5+2=7 counters out of 10. Probability = 7/10. [2]
The data are 4, 7, 7, 9, 13. Find the mean, median and mode.
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Mean = 40/5 = 8; median = 7; mode = 7. [3]
Further Topic Practice — Application, Practical Skills and Higher Demand
These additional original questions extend each syllabus area with practical contexts, explanation and multi-step reasoning. Mark allocations are stated explicitly; award equivalent scientifically correct wording where appropriate.
Biology — Further set (21 questions)
A student uses a dichotomous key to identify an unknown leaf. State two rules for constructing a reliable dichotomous key.
Show worked answer and marking guidance
Use observable features; each step offers two mutually exclusive alternatives; avoid subjective terms; direct each choice to another numbered step or an identification. [2]
Explain why the small intestine has a large surface area and a good blood supply.
Show worked answer and marking guidance
Large surface area increases diffusion/absorption; capillaries carry absorbed glucose and amino acids away, maintaining a concentration gradient. [2]
A red blood cell is placed in distilled water. Predict and explain what happens.
Show worked answer and marking guidance
Water enters by osmosis down the water-potential gradient through the partially permeable membrane; the cell swells and may burst because it has no cell wall. [3]
Describe the food tests for reducing sugar and protein, including positive results.
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Benedict's solution plus heating: blue changes through green/yellow/orange to brick-red precipitate. Biuret reagent: blue changes to lilac/purple. [3]
Describe how to investigate the effect of pH on amylase activity, identifying variables to control.
Show worked answer and marking guidance
Use buffer solutions of different pH; mix equal volumes/concentrations of amylase and starch at constant temperature; sample at intervals onto iodine; record time until iodine stays brown; repeat and calculate rate as 1/time. Control temperature, volumes and concentrations. [4]
Explain why a plant with magnesium deficiency may develop yellow leaves and grow slowly.
Show worked answer and marking guidance
Magnesium is needed to make chlorophyll; less chlorophyll reduces light absorption and photosynthesis; less glucose/biomass is produced, reducing growth. [3]
Explain the role of bile in digestion even though bile contains no digestive enzymes.
Show worked answer and marking guidance
Bile neutralises acidic chyme from the stomach to provide alkaline conditions for intestinal enzymes; emulsifies fats into small droplets, increasing surface area for lipase. [3]
A ring of bark is removed from a woody stem. Explain why sugars accumulate above the ring and roots may eventually die.
Show worked answer and marking guidance
Phloem in the bark is removed, interrupting translocation of sucrose; sugars accumulate above the cut; roots receive less carbohydrate for respiration and growth and may die. Xylem initially remains, so water transport can continue. [3]
Explain how haemoglobin is adapted to transport oxygen.
Show worked answer and marking guidance
Haemoglobin in red blood cells binds oxygen reversibly to form oxyhaemoglobin; it loads oxygen where partial pressure is high and releases it in respiring tissues where oxygen is lower. [2]
Explain why antibiotics do not cure influenza.
Show worked answer and marking guidance
Influenza is caused by a virus, not bacteria; antibiotics target bacterial structures/processes and do not act on viruses. [2]
Describe how ventilation maintains a steep oxygen concentration gradient between alveoli and blood.
Show worked answer and marking guidance
Fresh air continually enters alveoli, replenishing oxygen; blood flow removes oxygen from capillaries; this maintains higher oxygen concentration in alveolar air than in deoxygenated blood. [3]
Explain why muscle cells may accumulate lactic acid during intense exercise.
Show worked answer and marking guidance
Oxygen supply may not meet demand; muscle cells respire anaerobically; glucose is incompletely broken down and lactic acid accumulates, causing oxygen debt. [3]
Explain why urea is produced in the liver and removed by the kidneys.
Show worked answer and marking guidance
Excess amino acids are deaminated in the liver; the toxic ammonia formed is converted to less toxic urea; kidneys filter urea from blood into urine. [3]
Explain how insulin lowers blood glucose concentration after a carbohydrate-rich meal.
Show worked answer and marking guidance
Pancreatic beta cells release insulin; it increases uptake of glucose by cells and stimulates liver/muscle cells to convert glucose to glycogen; blood glucose falls towards normal. [3]
Distinguish between physical dependence and psychological dependence on a drug.
Show worked answer and marking guidance
Physical dependence involves body adaptation and withdrawal symptoms when use stops; psychological dependence is a perceived need/craving to continue using the drug. [2]
Explain the importance of having a large number of pollen grains and ovules/produced gametes in sexual reproduction.
Show worked answer and marking guidance
Many pollen grains increase the chance of pollination and fertilisation; many male gametes increase the chance that an egg is fertilised; reproductive cells are produced in excess because many are lost. [2]
A dominant allele B causes black fur and b causes white fur. A Bb animal is crossed with bb. Give the expected genotypes and phenotypes.
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Gametes: B or b from Bb; b from bb. Offspring: 50% Bb black and 50% bb white; phenotype ratio 1:1. [3]
Distinguish between continuous and discontinuous variation and give one example of each.
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Continuous variation has a range of values, e.g. height or mass, often influenced by many genes and environment. Discontinuous variation has distinct categories, e.g. blood group, usually controlled by one/few genes. [3]
Explain why decomposers are essential to nutrient cycles.
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Decomposers secrete enzymes onto dead material and waste, digesting it externally; they absorb soluble products and release mineral ions into soil/water for reuse by plants. [3]
Explain how excess nitrate fertiliser can cause fish deaths in a lake.
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Nitrates cause algal bloom; algae block light and plants die; decomposers break down dead material and respire, using dissolved oxygen; oxygen falls and fish suffocate. [4]
Explain why a fermenter is sterilised before microorganisms are added.
Show worked answer and marking guidance
Sterilisation kills unwanted microorganisms; prevents contamination and competition for nutrients/oxygen; avoids unwanted products and maintains a pure culture. [3]
Chemistry — Further set (12 questions)
Explain why evaporation causes cooling.
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The highest-energy particles escape from the liquid; the average kinetic energy of remaining particles decreases, so temperature falls. [2]
An element has isotopes with mass numbers 35 and 37 in a 3:1 abundance ratio. Calculate its relative atomic mass.
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(35×3 + 37×1) ÷ 4 = 142 ÷ 4 = 35.5. [2]
Calculate the number of moles in 5.6 g of iron. (Ar Fe=56).
Show worked answer and marking guidance
Moles = mass/Mr = 5.6/56 = 0.10 mol. [2]
State what happens at the electrodes during electrolysis of aqueous copper(II) sulfate using inert electrodes.
Show worked answer and marking guidance
Copper ions gain electrons at the cathode to form copper metal; hydroxide ions/water are oxidised at the anode to oxygen; solution becomes more acidic. [3]
A reaction has a temperature rise of 8 °C. Explain the energy change between reacting chemicals and surroundings.
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The reaction is exothermic; energy released by forming product bonds exceeds energy needed to break reactant bonds; energy is transferred to surroundings, raising temperature. [3]
Describe how a catalyst increases reaction rate without being used up.
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It provides an alternative reaction pathway with lower activation energy; a greater fraction of collisions are successful per second; catalyst is regenerated at the end. [3]
Write the ionic equation for neutralisation and identify the spectator ions in HCl + NaOH.
Show worked answer and marking guidance
H⁺(aq) + OH⁻(aq) → H₂O(l). Na⁺ and Cl⁻ are spectator ions. [2]
Describe the trend in reactivity down Group I and explain it using electron shells.
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Reactivity increases down the group; outer electron is farther from nucleus and more shielded, so attraction is weaker and electron is lost more easily. [3]
Explain why steel is harder than pure iron.
Show worked answer and marking guidance
Steel is an alloy containing atoms of different sizes; these distort the regular layers and make it harder for layers of atoms to slide over one another. [2]
Explain why catalytic converters reduce harmful exhaust emissions.
Show worked answer and marking guidance
Catalysts promote reactions converting carbon monoxide and nitrogen oxides into less harmful gases such as carbon dioxide and nitrogen; hydrocarbons are oxidised to carbon dioxide and water. [3]
State the products of complete combustion of a hydrocarbon and explain the condition needed for incomplete combustion.
Show worked answer and marking guidance
Complete combustion produces carbon dioxide and water with excess oxygen. Limited oxygen causes incomplete combustion, producing carbon monoxide and/or carbon (soot) plus water. [3]
A mixture of dyes is separated by paper chromatography. Explain why spots travel different distances and how Rf is calculated.
Show worked answer and marking guidance
Dyes have different solubilities in the solvent and attractions to paper, so move at different rates. Rf = distance moved by substance ÷ distance moved by solvent front. [3]
Physics — Further set (6 questions)
A 2.0 kg trolley accelerates at 3.0 m/s². Calculate the resultant force and state its direction relative to acceleration.
Show worked answer and marking guidance
F=ma=2.0×3.0=6.0 N; resultant force acts in the direction of acceleration. [2]
Describe an experiment to compare thermal conductivity of different metal rods.
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Use rods of equal dimensions, attach drawing pins with wax at equal distances, heat one end equally, and compare time/order pins fall; repeat under same conditions. Faster pin fall indicates better conductor. [3]
A sound wave travels at 340 m/s and has frequency 680 Hz. Calculate its wavelength.
Show worked answer and marking guidance
v=fλ, so λ=v/f=340/680=0.50 m. [2]
Explain why a fuse is connected in the live wire and how it protects a circuit.
Show worked answer and marking guidance
Excess current heats and melts the fuse wire, breaking the circuit; in the live wire this disconnects the appliance from the dangerous supply voltage. [2]
Compare alpha, beta and gamma radiation in terms of penetration and ionisation.
Show worked answer and marking guidance
Alpha: least penetrating, most ionising; beta: medium penetration and ionisation; gamma: most penetrating, least ionising. [3]
Explain the redshift observed in light from distant galaxies and what it suggests about the Universe.
Show worked answer and marking guidance
Wavelengths are shifted towards the red/longer wavelengths because galaxies are moving away; this supports the conclusion that the Universe is expanding. [2]
Mathematics — Further set (9 questions)
Write 0.000572 in standard form and give the value to 2 significant figures.
Show worked answer and marking guidance
5.72×10⁻⁴; to 2 significant figures, 5.7×10⁻⁴. [2]
Factorise fully 6x² − 15x.
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3x(2x−5). [2]
Find the equation of a straight line with gradient 3 passing through (2, −1).
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y=3x+c; −1=6+c, so c=−7. Equation: y=3x−7. [3]
The exterior angle of a regular polygon is 24°. Find the number of sides.
Show worked answer and marking guidance
Exterior angles sum to 360°; number of sides = 360/24 = 15. [2]
A cone has radius 4 cm and perpendicular height 9 cm. Find its volume in terms of π.
Show worked answer and marking guidance
V=⅓πr²h = ⅓×π×16×9 = 48π cm³. [2]
In a triangle, two sides are 7 cm and 9 cm with included angle 60°. Calculate the third side.
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Cosine rule: c²=7²+9²−2×7×9×cos60°=49+81−63=67; c=√67≈8.19 cm. [3]
Describe fully the transformation mapping (x,y) to (−y,x).
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Rotation 90° anticlockwise about the origin. [2]
Two fair six-sided dice are rolled. Find the probability that the total is 8.
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Favourable outcomes: (2,6),(3,5),(4,4),(5,3),(6,2): 5 out of 36. Probability 5/36. [2]
The times (minutes) are 12, 15, 17, 18, 28. Calculate the range and median.
Show worked answer and marking guidance
Range=28−12=16; median is the middle value, 17. [2]
Scientific investigation skills — Biology, Chemistry and Physics
A learner investigates how light intensity affects the rate of photosynthesis using pondweed. Identify the independent variable, dependent variable and two variables to control. Explain why one control is important.
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Independent: light intensity/distance of lamp. Dependent: oxygen bubbles per minute or oxygen volume per unit time. Controls may include temperature, carbon dioxide concentration, pondweed species/length. Temperature must be controlled because it affects enzyme activity and photosynthesis rate. [4]
Three repeat measurements of a reaction time are 42 s, 39 s and 63 s. Identify the anomalous result, calculate the mean of the remaining results and state one way to improve reliability.
Show marking guidance
63 s is anomalous; mean=(42+39)/2=40.5 s. Repeat more trials, identify and investigate anomalies, and calculate a mean from concordant results. [4]
When plotting a graph from experimental data, state four features of a scientifically appropriate graph.
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Independent variable on x-axis; dependent variable on y-axis; axes labelled with quantity and unit; suitable even scale; points plotted accurately; best-fit line/curve rather than dot-to-dot where appropriate. Any four. [4]
High-Volume Practice Bank — Set 3
85 additional original questions across Core and Extended skills. This set increases practice variety with multi-step calculations, data interpretation, experimental reasoning, explanation and real-life contexts. All are CBE Nexus-created, not official Cambridge examination questions.
Biology — Set 3 · 20 questions
A newly discovered organism is multicellular, has cellulose cell walls and chloroplasts. Identify its kingdom and justify the choice.
Show worked answer and marking guidance
Plant kingdom: multicellular, cellulose cell walls and chloroplasts for photosynthesis. [2]
A cell has a high rate of protein synthesis. Name the organelles expected to be numerous and explain their roles.
Show worked answer and marking guidance
Ribosomes synthesise proteins; rough endoplasmic reticulum transports/processes proteins; many mitochondria provide ATP for synthesis and transport. [3]
An image of a cell is 36 mm long. Its actual length is 60 μm. Calculate magnification.
Show worked answer and marking guidance
Convert 36 mm to 36 000 μm. Magnification = image size ÷ actual size = 36 000/60 = ×600. [2]
Potato cylinders are placed in sucrose solutions. Explain how percentage change in mass can be used to estimate the concentration with the same water potential as potato cells.
Show worked answer and marking guidance
Measure initial and final masses, calculate percentage change; plot against sucrose concentration; the concentration where percentage change is zero is the isotonic concentration. [3]
Explain why glycogen is suitable as an energy store in animals.
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It is insoluble so does not affect water potential; compact; can be hydrolysed to glucose for respiration when required. [2]
Explain why enzymes are described as biological catalysts and are specific.
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They speed up metabolic reactions without being used up; the active site has a complementary shape to a particular substrate, giving specificity. [2]
A plant is grown in air with very little carbon dioxide. Predict the effect on glucose production and explain.
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Glucose production decreases because carbon dioxide is a raw material for photosynthesis; low CO₂ limits the rate even if light and temperature are suitable. [2]
Explain why chewing food increases the rate of chemical digestion.
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Chewing breaks food into smaller pieces, increasing surface area for digestive enzymes; mixing with saliva moistens food and starts starch digestion. [2]
Explain how root hair cells are adapted for uptake of mineral ions from dilute soil solution.
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Long projections give large surface area; carrier proteins in membranes transport ions; active transport uses energy from respiration to move ions against concentration gradients. [3]
Describe the pathway of blood through the heart and lungs, starting at the vena cava.
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Vena cava → right atrium → right ventricle → pulmonary artery → lungs → pulmonary veins → left atrium → left ventricle → aorta. [4]
Explain the difference between active and passive immunity.
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Active: body makes its own antibodies and memory cells after infection/vaccination; usually long-lasting. Passive: ready-made antibodies are received; immediate but temporary and no memory cells. [3]
Explain why exhaled air contains less oxygen and more carbon dioxide than inhaled air.
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Oxygen diffuses from alveoli into blood and is used in aerobic respiration; carbon dioxide produced by respiration is transported in blood and diffuses into alveoli. [3]
Calculate the energy transfer efficiency if 500 J of energy is transferred to a consumer from 2500 J available in the previous trophic level.
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Efficiency = (500/2500) × 100 = 20%. [2]
Explain why kidney failure can be life-threatening.
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Urea and other wastes accumulate; water and ion balance may be disrupted; toxic changes in blood composition affect cell function and can be fatal. [2]
Compare nervous and hormonal coordination in terms of transmission and speed.
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Nervous: electrical impulses along neurones, rapid, localised and short-lived. Hormonal: chemical hormones carried in blood, slower, often longer-lasting and more widespread. [3]
Describe the events from pollination to seed formation in a flowering plant.
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Pollen lands on stigma; pollen tube grows down style; male nucleus travels to ovule; fertilisation occurs when it fuses with egg nucleus; ovule develops into seed and ovary into fruit. [4]
A woman with genotype XᴺXⁿ and a man XᴺY have a child. State the probability of a son being affected by an X-linked recessive condition.
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A son receives Y from father and one X from mother; half of sons receive Xⁿ and are affected. Probability among sons = 1/2 (50%). [2]
Explain how antibiotic-resistant bacteria become more common in a population.
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Random mutation may produce resistance; antibiotic kills susceptible bacteria; resistant bacteria survive, reproduce rapidly and pass resistance allele to offspring. [3]
Explain why the pyramid of biomass is usually upright in a terrestrial ecosystem.
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Biomass represents stored chemical energy; energy and material are lost between trophic levels through respiration, waste and uneaten parts, so less biomass is supported at higher levels. [3]
Give two potential benefits and one possible concern of genetically modified crop plants.
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Benefits: increased yield, pest resistance, improved nutrition or tolerance to drought/herbicides. Concern: gene transfer to wild relatives, effects on non-target organisms, reduced biodiversity or economic dependence. [3]
Chemistry — Set 3 · 20 questions
A gas diffuses faster at higher temperature. Explain using kinetic particle theory.
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Particles have greater average kinetic energy and move faster; they spread through the available space more quickly. [2]
Describe how to separate a mixture of ethanol and water and name the apparatus.
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Fractional distillation using a fractionating column and condenser; ethanol has the lower boiling point and distils first. [2]
An atom has electron arrangement 2,8,7. State its group, period and likely ion charge.
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Group VII/17; Period 3; gains one electron to form a 1− ion. [3]
Explain why graphite conducts electricity but diamond does not.
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Each graphite carbon bonds to three others, leaving one delocalised electron per atom able to move; diamond uses all four outer electrons in covalent bonds. [3]
Write the formula of aluminium oxide using Al³⁺ and O²⁻ ions and explain the ratio.
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Al₂O₃; two Al³⁺ ions give +6 and three O²⁻ ions give −6, making a neutral compound. [2]
Calculate the mass of 0.25 mol of carbon dioxide. (Ar C=12, O=16).
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Mr CO₂ = 12 + 2(16) = 44; mass = moles × Mr = 0.25×44 = 11 g. [2]
Predict the products at the electrodes when concentrated aqueous sodium chloride is electrolysed using inert electrodes.
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Cathode: hydrogen; anode: chlorine; sodium hydroxide remains in solution. [3]
State the overall reaction in a hydrogen-oxygen fuel cell and one advantage over combustion engines.
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2H₂ + O₂ → 2H₂O. It produces water at point of use and converts chemical energy directly to electrical energy efficiently. [2]
Use bond energies to determine the energy change when bonds broken require 950 kJ/mol and bonds formed release 1250 kJ/mol.
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Energy change = energy to break − energy released forming = 950−1250 = −300 kJ/mol; exothermic. [2]
For N₂ + 3H₂ ⇌ 2NH₃, predict the effect of increasing pressure on equilibrium position and explain.
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Equilibrium shifts right, towards fewer gas molecules (2 moles rather than 4), reducing pressure; ammonia yield increases. [2]
In the reaction CuO + H₂ → Cu + H₂O, identify the substance oxidised and the substance reduced.
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Hydrogen is oxidised to water (gains oxygen); copper(II) oxide is reduced to copper (loses oxygen). [2]
A solution has pH 2. Another has pH 4. How many times greater is the hydrogen ion concentration in the first solution?
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A difference of 2 pH units represents 10² = 100 times; pH 2 solution has 100 times greater hydrogen ion concentration. [2]
Explain why aluminium is used for aircraft bodies despite being reactive.
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It has low density and forms a thin, adherent aluminium oxide layer that prevents further corrosion; alloys improve strength. [2]
Describe a test for water and state the positive result.
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Anhydrous copper(II) sulfate changes from white to blue; alternatively cobalt chloride paper changes blue to pink. [2]
Describe addition polymerisation of ethene.
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Many ethene molecules open their C=C double bonds and join to form a long-chain polymer with repeating –CH₂–CH₂– units; poly(ethene). [3]
Explain why fractional distillation separates crude oil into fractions.
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Hydrocarbons have different boiling points due to different molecular sizes/intermolecular forces; vapours condense at different temperatures/heights in the fractionating column. [3]
Describe the oxidation of ethanol and give one condition and product.
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Ethanol is oxidised to ethanoic acid using an oxidising agent such as acidified potassium dichromate(VI) under reflux; colour changes orange to green. [3]
Write the equation for ethanoic acid reacting with sodium carbonate.
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2CH₃COOH + Na₂CO₃ → 2CH₃COONa + H₂O + CO₂. [2]
A gas turns limewater milky. Identify the gas and explain the observation.
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Carbon dioxide; it reacts with calcium hydroxide to form insoluble calcium carbonate, a white precipitate. [2]
Explain why a burette is rinsed with the solution it will contain before a titration.
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Rinsing removes residual water/contaminants that could dilute or react with the solution and change its concentration, improving accuracy. [2]
Physics — Set 3 · 20 questions
A measuring cylinder has scale divisions of 2 cm³. State a suitable reading uncertainty for one reading and one way to reduce percentage uncertainty.
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Typically ±1 cm³ for a single reading (half the smallest division); measure a larger volume or repeat readings and average where appropriate. [2]
A velocity-time graph is a straight line rising from 0 to 12 m/s over 6 s. Calculate acceleration and distance travelled.
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Acceleration = gradient = 12/6 = 2 m/s². Distance = area under graph = ½×6×12 = 36 m. [3]
A 0.20 kg ball changes velocity from +8 m/s to −4 m/s in 0.10 s. Calculate the average resultant force.
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Change in velocity = −12 m/s; acceleration = −12/0.10 = −120 m/s²; F=ma=0.20×−120=−24 N (opposite initial direction). [3]
A 2 kg trolley moving at 3 m/s collides and sticks to a stationary 1 kg trolley. Calculate their common speed.
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Conservation of momentum: (2×3)+(1×0)=(2+1)v; v=6/3=2 m/s. [2]
A motor transfers 600 J of useful energy from 1000 J supplied. Calculate efficiency.
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Efficiency = useful output/input ×100 = 600/1000×100 = 60%. [2]
Calculate the pressure exerted by a force of 150 N on an area of 0.030 m².
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p=F/A=150/0.030=5000 Pa. [2]
Explain why a vacuum flask reduces thermal energy transfer by conduction, convection and radiation.
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Vacuum prevents conduction and convection between walls; silvered surfaces reflect infrared radiation; insulating stopper reduces conduction/convection through opening. [3]
A 2 kg block absorbs 8400 J and its temperature rises by 10 °C. Calculate its specific heat capacity.
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E=mcΔT; c=8400/(2×10)=420 J kg⁻¹ °C⁻¹. [2]
A gas at constant temperature has pressure 100 kPa and volume 300 cm³. It is compressed to 200 cm³. Calculate the new pressure.
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p₁V₁=p₂V₂; p₂=(100×300)/200=150 kPa. [2]
A wave has period 0.004 s. Calculate its frequency.
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f=1/T=1/0.004=250 Hz. [2]
A ray enters glass from air and bends towards the normal. Explain why.
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Light slows down as it enters the optically denser glass; one side of the wavefront slows first, causing the ray to change direction towards the normal. [2]
Explain why sound cannot travel through a vacuum.
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Sound is a mechanical wave that transfers energy by vibrations of particles; a vacuum has no particles to vibrate and pass on the disturbance. [2]
A 4 Ω resistor and 8 Ω resistor are connected in series to a 24 V supply. Calculate total resistance and current.
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Rtotal=4+8=12 Ω; I=V/R=24/12=2 A. [2]
A 2 kW kettle operates for 3 minutes. Calculate the energy transferred in joules.
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E=Pt=2000×180=360 000 J. [2]
Describe how to determine the direction of the magnetic field around a straight current-carrying wire.
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Use the right-hand grip rule: thumb points in direction of conventional current; curled fingers show the magnetic field direction. [2]
State two ways to increase the induced voltage in a coil moving in a magnetic field.
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Move the coil/magnet faster; use a stronger magnetic field; increase number of turns; use a suitable core. Any two. [2]
A transformer has 500 turns on the primary and 50 turns on the secondary. The primary voltage is 240 V. Calculate secondary voltage.
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Vs/Vp=Ns/Np; Vs=240×50/500=24 V. [2]
Explain why radioactive decay is described as random and spontaneous.
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It is impossible to predict which nucleus will decay or exactly when; decay occurs without an external trigger and is unaffected by ordinary physical/chemical conditions. [2]
Complete the alpha decay equation: ²³⁸₉₂U → ? + ⁴₂He.
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²³⁴₉₀Th; mass number decreases by 4 and proton number by 2. [2]
Explain why the orbital speed of a planet is greater when it is closer to the Sun in an elliptical orbit.
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The Sun's gravitational attraction is stronger at smaller distance; the planet accelerates more and moves faster near the Sun, consistent with conservation of angular momentum. [2]
Mathematics — Set 3 · 25 questions
Evaluate 3/4 − 2/5, giving your answer as a simplified fraction.
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Common denominator 20: 15/20−8/20=7/20. [2]
A population of bacteria increases by 8% each hour. It starts at 500. Calculate the population after 2 hours, to the nearest whole number.
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500×1.08²=583.2, so approximately 583 bacteria. [2]
In a class of 30, 18 study Biology, 14 study Chemistry and 6 study neither. Find how many study both.
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At least one =30−6=24. Using n(B∪C)=18+14−both, both=32−24=8. [3]
Simplify (x⁵ × x³) ÷ x².
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x^(5+3−2)=x⁶. [2]
Simplify √72.
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√(36×2)=6√2. [2]
A length is recorded as 8.4 cm to the nearest 0.1 cm. Write the lower and upper bounds.
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Lower bound 8.35 cm; upper bound 8.45 cm (upper bound excluded in the interval convention). [2]
Share KSh 840 in the ratio 2:3:7.
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Total parts=12; one part=840/12=70. Shares: 140, 210 and 490. [3]
A car travels 156 km in 2 hours 24 minutes. Calculate its average speed in km/h.
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2 h 24 min =2.4 h; speed=156/2.4=65 km/h. [2]
Expand and simplify (2x−3)(x+5).
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2x²+10x−3x−15=2x²+7x−15. [2]
Solve 5−2(3x−1)=4x+1.
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5−6x+2=4x+1; 6=10x; x=0.6. [3]
Solve 3x−5 ≤ 10.
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3x≤15, so x≤5. [2]
Find the nth term of 7, 11, 15, 19, …
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Common difference 4; nth term =4n+3. [2]
Given f(x)=2x−3, find f⁻¹(x).
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Let y=2x−3; swap x and y: x=2y−3; y=(x+3)/2. [3]
Find the midpoint of A(−4, 7) and B(6, −1).
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Midpoint=((−4+6)/2,(7−1)/2)=(1,3). [2]
A line has gradient −2. Find the gradient of a line perpendicular to it.
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Negative reciprocal =1/2. [2]
An exterior angle of a triangle is 128°. One opposite interior angle is 53°. Find the other opposite interior angle.
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Exterior angle equals sum of two opposite interior angles; 128−53=75°. [2]
The angle at the centre of a circle is 116°. Find the angle at the circumference subtended by the same arc.
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Angle at circumference is half angle at centre =58°. [2]
A sector has radius 7 cm and angle 90°. Find its area in terms of π.
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Area=(90/360)π×7²=49π/4 cm². [2]
A ladder 5 m long rests against a vertical wall. Its foot is 1.2 m from the wall. Calculate the height reached.
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h²=5²−1.2²=25−1.44=23.56; h=√23.56≈4.85 m. [3]
Given a=(2,−1) and b=(−3,4), find 2a−b.
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2a=(4,−2); 2a−b=(4−(−3),−2−4)=(7,−6). [2]
A bag contains 4 red and 6 blue balls. Two balls are drawn without replacement. Find the probability both are red.
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P=4/10×3/9=12/90=2/15. [2]
The mean of five numbers is 12. Four numbers are 8, 10, 13 and 15. Find the fifth number.
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Total=5×12=60; known sum=46; fifth=14. [2]
State how the median is estimated from a cumulative frequency graph for 80 observations.
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Locate cumulative frequency 40 (N/2), draw to the curve, then down to the data axis to read the median. [2]
Differentiate y=3x²−4x+7 and find the gradient at x=2.
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dy/dx=6x−4; at x=2, gradient=12−4=8. [3]
Describe the transformation from y=f(x) to y=f(x)+4.
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Translation 4 units upwards, parallel to the y-axis. [2]
This Set 3 adds 85 original questions. Continue using the syllabus checklist: question volume alone does not guarantee complete coverage of every syllabus statement, practical skill or Core/Supplement distinction.