IGCSE Biology Practice Test 10 – 60 Questions with Answers (Cambridge 0610)
This final test in the set is a full-syllabus revision check, so mark it honestly and use the results to plan your last round of study.
Characteristics and classification of living organisms
Q1. Which life process is shown when a bacterium divides into two?
- (A) Reproduction
- (B) Excretion
- (C) Sensitivity to stimuli
- (D) Nutrition
Show Answer
Answer: A – Reproduction produces new individuals, in this case by cell division.
Q2. Which feature is shared by all arthropods?
- (A) A soft unsegmented body
- (B) A shell made of calcium carbonate
- (C) Jointed legs and an exoskeleton
- (D) Four limbs and lungs
Show Answer
Answer: C – Arthropods are defined by jointed appendages and a hard external skeleton.
Q3. Which kingdom includes multicellular organisms that photosynthesise?
- (A) Animalia
- (B) Plantae
- (C) Fungi
- (D) Protoctista only
Show Answer
Answer: B – Plants are multicellular photosynthetic organisms with cellulose cell walls.
Organisation of the organism
Q4. Which structure is an organ system in a plant?
- (A) A single xylem vessel in the stem
- (B) A chloroplast
- (C) A palisade cell
- (D) A shoot with stem, leaves and buds
Show Answer
Answer: D – The shoot system combines organs that work together for photosynthesis and support.
Q5. Which cell adaptation helps a sperm cell reach and fertilise an egg?
- (A) A large vacuole for storing nutrients and waste products
- (B) Many chloroplasts
- (C) A flagellum and many mitochondria for energy
- (D) A thick cell wall
Show Answer
Answer: C – The tail swims the sperm forward and mitochondria supply energy for movement.
Q6. Which tissue transports sugars in a plant stem?
- (A) Epidermis
- (B) Cortex
- (C) Mesophyll
- (D) Phloem
Show Answer
Answer: D – Phloem tissue contains sieve tubes that carry dissolved sugars.
Movement into and out of cells
Q7. Which process moves glucose from the gut into blood capillaries in the villi?
- (A) Diffusion down a concentration gradient
- (B) Active transport only in the colon after digestion
- (C) Osmosis through the wall
- (D) Transpiration
Show Answer
Answer: A – Digested glucose diffuses across the thin villus wall into capillary blood.
Q8. Which factor would slow osmosis into a potato cylinder?
- (A) A higher water potential outside the potato cells
- (B) A lower water potential outside the cells
- (C) A larger surface area
- (D) A thinner cylinder
Show Answer
Answer: B – A lower external water potential reduces or reverses net water movement into cells.
Q9. In which situation is active transport essential?
- (A) Oxygen entering a lung capillary from alveoli
- (B) Water entering a root hair by osmosis
- (C) Carbon dioxide leaving a leaf
- (D) Ions entering a root from dilute soil water
Show Answer
Answer: D – Ions must be pumped against a gradient when soil water is more dilute than cell sap.
Biological molecules
Q10. Which molecule is a disaccharide formed from two glucose units?
- (A) Maltose
- (B) Starch
- (C) Cellulose
- (D) Glycerol
Show Answer
Answer: A – Maltose is two glucose molecules joined together, produced during starch digestion.
Q11. Which test result shows that a food contains protein?
- (A) Blue-black with iodine
- (B) Brick-red with Benedict’s solution
- (C) Purple with biuret solution
- (D) Milky emulsion with ethanol
Show Answer
Answer: C – Biuret reagent turns purple when peptide bonds in protein are present.
Q12. Which statement about water as a biological molecule is correct?
- (A) It is a poor solvent
- (B) It is a solvent for many substances in cells
- (C) It cannot take part in reactions inside cells
- (D) It is stored as starch
Show Answer
Answer: B – Water dissolves ions and small molecules, allowing reactions and transport in cells.
Enzymes
Q13. Which enzyme digests proteins in the small intestine at alkaline pH?
- (A) Amylase
- (B) Lipase
- (C) Pepsin
- (D) Trypsin
Show Answer
Answer: D – Trypsin is secreted by the pancreas and works in the alkaline duodenum.
Q14. A student plots enzyme activity against temperature and finds a peak at 37 degrees Celsius. What is this temperature?
- (A) The denaturation point only
- (B) The optimum temperature
- (C) The freezing point
- (D) The boiling point
Show Answer
Answer: B – The optimum is the temperature at which activity is highest before denaturation reduces it.
Q15. Which statement explains why enzymes are specific?
- (A) They are large molecules made of many amino acids joined together
- (B) They dissolve in water
- (C) Only a substrate with a matching shape fits the active site
- (D) They work in all organisms
Show Answer
Answer: C – Active site shape determines which substrate can bind, giving each enzyme specificity.
Plant nutrition
Q16. Which condition is needed for a leaf to produce starch in a photosynthesis experiment?
- (A) Light, carbon dioxide and chlorophyll
- (B) Darkness and oxygen only, without any light
- (C) Water and soil only
- (D) Heat without light
Show Answer
Answer: A – Photosynthesis needs light energy, carbon dioxide, water and chlorophyll.
Q17. A plant is given extra nitrate fertiliser. Which growth effect is expected?
- (A) Yellow leaves and stunted growth in all plants
- (B) Improved leaf growth and greener leaves
- (C) No change in any plant
- (D) Loss of roots only
Show Answer
Answer: B – Nitrate supplies nitrogen for proteins and chlorophyll, improving growth.
Q18. Which statement about limiting factors is correct?
- (A) Increasing a limiting factor increases the rate
- (B) Limiting factors only affect animals
- (C) Light is never a limiting factor
- (D) Temperature has no effect on photosynthesis in plants
Show Answer
Answer: A – The rate is controlled by the factor in shortest supply, so raising it raises the rate.
Human nutrition
Q19. Which part of the digestive system absorbs water from undigested food?
- (A) Stomach
- (B) Ileum
- (C) Duodenum
- (D) Colon
Show Answer
Answer: D – The colon absorbs water and salts, forming faeces from undigested material.
Q20. Which diet problem is linked to eating too much saturated fat and too little exercise?
- (A) Scurvy
- (B) Rickets
- (C) Coronary heart disease
- (D) Anaemia from lack of iron in the diet
Show Answer
Answer: C – Excess saturated fat raises cholesterol and artery blockage risk, especially with inactivity.
Transport in plants
Q21. Which tissue is damaged if a ring of bark is removed from a tree stem?
- (A) Xylem only
- (B) Phloem
- (C) Epidermis only
- (D) Pith only
Show Answer
Answer: B – Phloem lies just under the bark, so removing bark cuts sugar transport to roots.
Q22. Which adaptation reduces water loss from a leaf in a dry habitat?
- (A) Many stomata on the upper surface of the leaf
- (B) Thin cuticle
- (C) Large flat leaves
- (D) Thick waxy cuticle and sunken stomata
Show Answer
Answer: D – A thick cuticle and sunken stomata trap moist air and slow evaporation.
Transport in animals
Q23. Which heart valve prevents blood flowing back from the left ventricle into the left atrium?
- (A) Bicuspid valve
- (B) Semilunar valve in the aorta
- (C) Tricuspid valve
- (D) Valve in the vena cava
Show Answer
Answer: A – The bicuspid, or mitral, valve closes when the left ventricle contracts.
Q24. Which statement about capillaries is correct?
- (A) They have thick muscular walls
- (B) They contain valves to prevent backflow of blood to the heart
- (C) They allow exchange by diffusion through thin walls
- (D) They carry blood at high pressure
Show Answer
Answer: C – Capillary walls are one cell thick and blood flows slowly, favouring exchange.
Diseases and immunity
Q25. How is HIV transmitted?
- (A) By coughing in the same room as an infected person
- (B) Through blood and sexual contact with infected fluids
- (C) By sharing food
- (D) By mosquito bites in all cases
Show Answer
Answer: B – HIV spreads through infected blood and sexual fluids, not by casual contact.
Q26. Which statement about the immune response to a first infection is correct?
- (A) Antibodies are made instantly without any delay at all in the body
- (B) Memory cells are made before infection
- (C) No response occurs
- (D) Antibody production is slow at first, then memory cells remain
Show Answer
Answer: D – The first response takes days, but memory cells allow a faster second response.
Q27. Which treatment is used against a bacterial disease?
- (A) Antibiotics
- (B) Antiviral drugs only
- (C) Vaccination after cure only
- (D) Painkillers that kill bacteria
Show Answer
Answer: A – Antibiotics kill or prevent growth of bacteria, though they do not affect viruses.
Gas exchange in humans
Q28. Which part of the breathing system is lined with cilia and mucus?
- (A) Alveolus
- (B) Diaphragm
- (C) Trachea and bronchi
- (D) Pleural membrane around the lungs
Show Answer
Answer: C – Ciliated epithelium in airways traps dust and moves mucus upwards.
Q29. What is the percentage of oxygen in inhaled air, approximately?
- (A) 21 percent
- (B) 16 percent
- (C) 4 percent
- (D) 0.04 percent
Show Answer
Answer: A – Inhaled air is about 21 percent oxygen, falling to about 16 percent in exhaled air.
Q30. Which adaptation of the lungs gives a large area for gas exchange?
- (A) A single large air sac
- (B) Thick alveolar walls
- (C) Few capillaries
- (D) Millions of alveoli
Show Answer
Answer: D – Millions of tiny alveoli together provide a very large surface area.
Respiration
Q31. Which statement about anaerobic respiration in yeast is correct?
- (A) It produces lactic acid
- (B) It produces ethanol and carbon dioxide
- (C) It needs oxygen
- (D) It releases more energy than aerobic respiration
Show Answer
Answer: B – Yeast ferments glucose to ethanol and carbon dioxide, used in brewing and baking.
Q32. Which experiment shows that oxygen is used up during respiration?
- (A) Limewater turning milky
- (B) A thermometer showing a rise
- (C) A decrease in oxygen shown by a sensor or indicator
- (D) A leaf turning blue-black with iodine solution after testing
Show Answer
Answer: C – Oxygen uptake can be measured directly, for example with a respirometer.
Q33. Why do athletes breathe heavily after a sprint?
- (A) To repay the oxygen debt from anaerobic respiration
- (B) To remove excess oxygen from the blood quickly after exercise
- (C) To cool the lungs
- (D) To increase carbon dioxide storage
Show Answer
Answer: A – Extra oxygen breaks down lactic acid built up during anaerobic work.
Excretion in humans
Q34. Which part of the kidney tubule is responsible for most reabsorption?
- (A) Glomerulus in the kidney cortex
- (B) Proximal convoluted tubule
- (C) Bladder
- (D) Urethra
Show Answer
Answer: B – The first tubule reabsorbs glucose, amino acids, salts and much water into blood.
Q35. A person drinks very little water on a hot day. What will the kidneys produce?
- (A) A large volume of dilute urine
- (B) No urine at all for days
- (C) Blood with extra urea only
- (D) A small volume of concentrated urine
Show Answer
Answer: D – Antidiuretic hormone increases water reabsorption, conserving water.
Q36. Which substance is at a higher concentration in renal artery blood than in renal vein blood because kidney cells use it in respiration?
- (A) Carbon dioxide
- (B) Plasma proteins
- (C) Oxygen
- (D) Water
Show Answer
Answer: C – Kidney cells respire actively, using oxygen from arterial blood, so venous blood has less oxygen.
Coordination and response
Q37. In bright light, what happens to the pupil?
- (A) It dilates to let in more light
- (B) It stays the same size
- (C) It closes completely
- (D) It constricts to reduce light entering
Show Answer
Answer: D – Circular iris muscles contract in bright light, narrowing the pupil to protect the retina.
Q38. Which gland releases thyroxine?
- (A) Thyroid gland
- (B) Pancreas
- (C) Adrenal gland
- (D) Pituitary gland only
Show Answer
Answer: A – The thyroid gland in the neck produces thyroxine, which controls metabolic rate.
Q39. Which response helps a plant shoot grow away from gravity?
- (A) Phototropism
- (B) Thigmotropism
- (C) Negative geotropism
- (D) Chemotropism
Show Answer
Answer: C – Shoots show negative geotropism, growing upwards against gravity.
Drugs
Q40. Which statement about smoking during pregnancy is correct?
- (A) It has no effect on the baby
- (B) It reduces oxygen supply and can cause low birth weight
- (C) It improves lung development
- (D) It prevents infection
Show Answer
Answer: B – Carbon monoxide reduces oxygen delivery to the fetus, increasing risks for the baby.
Q41. Which drug is an example of a painkiller that can be misused?
- (A) Morphine
- (B) Vitamin C
- (C) Insulin
- (D) Penicillin
Show Answer
Answer: A – Morphine is a powerful painkiller derived from opium that can cause dependence.
Q42. Why does alcohol impair driving ability?
- (A) It sharpens vision
- (B) It slows reactions and reduces coordination
- (C) It increases concentration
- (D) It removes tiredness permanently
Show Answer
Answer: B – Alcohol depresses the central nervous system, slowing responses and judgement.
Reproduction
Q43. Which event occurs at ovulation?
- (A) Fertilisation in the uterus
- (B) Implantation of the embryo
- (C) Birth of a baby
- (D) Release of an egg from the ovary
Show Answer
Answer: D – Ovulation is the release of a mature egg from a follicle into the oviduct.
Q44. Which seed structure stores food for germination?
- (A) Testa
- (B) Plumule
- (C) Cotyledon
- (D) Radicle
Show Answer
Answer: C – Cotyledons store starch and other food used by the embryo during germination.
Q45. Which statement about wind-pollinated flowers is correct?
- (A) They have large colourful petals
- (B) They produce sweet nectar
- (C) They produce large amounts of light pollen and feathery stigmas
- (D) They open only at night
Show Answer
Answer: C – Wind pollination relies on abundant light pollen and large feathery stigmas to catch it.
Inheritance
Q46. Which process ensures that chromosome number stays constant from generation to generation?
- (A) Mitosis only
- (B) Fertilisation only
- (C) Growth only
- (D) Meiosis followed by fertilisation
Show Answer
Answer: D – Meiosis halves the number and fertilisation restores the full diploid number.
Q47. A gene has alleles R (red) and r (white), with R dominant. What colour are Rr flowers?
- (A) Red
- (B) White
- (C) Pink
- (D) Half red and half white
Show Answer
Answer: A – The dominant allele masks the recessive allele in heterozygous plants.
Q48. Which statement about codominance is correct?
- (A) One allele is always hidden
- (B) Both alleles are expressed in the phenotype
- (C) Only the maternal allele is expressed
- (D) No protein is produced
Show Answer
Answer: B – In codominance, such as AB blood group, both alleles contribute to the phenotype.
Variation and selection
Q49. Which graph shape is typical for continuous variation?
- (A) Separate bars with gaps
- (B) Two distinct peaks only
- (C) A smooth bell-shaped curve
- (D) A single flat line
Show Answer
Answer: C – Continuous traits cluster around a mean, giving a normal distribution curve.
Q50. Which statement about evolution by natural selection is correct?
- (A) Populations change over generations as allele frequencies shift
- (B) Acquired traits are inherited
- (C) Individuals change during their lifetime
- (D) Organisms evolve because they want to change
Show Answer
Answer: A – Selection changes which alleles are common in a population over generations.
Q51. Which source of variation is caused by reshuffling of alleles during gamete formation?
- (A) Cloning
- (B) Asexual reproduction
- (C) Environmental change
- (D) Independent assortment and crossing over in meiosis
Show Answer
Answer: D – Meiosis shuffles alleles into new combinations in gametes.
Organisms and their environment
Q52. Which organism is a producer in a pond food web?
- (A) Water flea
- (B) Pondweed
- (C) Fish
- (D) Heron
Show Answer
Answer: B – Pondweed photosynthesises and forms the base of the pond food web.
Q53. Which process is carried out by nitrifying bacteria in soil?
- (A) Fixing nitrogen gas
- (B) Denitrification
- (C) Photosynthesis
- (D) Converting ammonium compounds to nitrates
Show Answer
Answer: D – Nitrifying bacteria convert ammonium to nitrites and then to nitrates for plant uptake.
Q54. Which factor is an abiotic factor in a woodland?
- (A) Number of predators
- (B) Competition for food
- (C) Soil pH
- (D) Disease spread
Show Answer
Answer: C – Soil pH is a non-living factor, while predators, competition and disease are biotic.
Human influences on ecosystems
Q55. Which farming method reduces soil erosion?
- (A) Contour ploughing and planting trees as windbreaks
- (B) Ploughing up and down steep slopes
- (C) Removing all hedgerows
- (D) Leaving soil bare all winter
Show Answer
Answer: A – Contour ploughing slows water run-off and windbreaks reduce wind erosion.
Q56. Which pollutant causes damage to the ozone layer?
- (A) Carbon dioxide
- (B) Chlorofluorocarbons
- (C) Sulfur dioxide only
- (D) Methane only
Show Answer
Answer: B – Chlorofluorocarbons break down ozone in the stratosphere, increasing ultraviolet radiation.
Q57. Which action is an example of sustainable use of a resource?
- (A) Fishing a stock to extinction
- (B) Cutting all trees in a forest at once
- (C) Replanting trees after harvesting timber
- (D) Draining a wetland for building
Show Answer
Answer: C – Replanting replaces what is taken, so the resource can be used again.
Biotechnology and genetic modification
Q58. Which product is made by fermentation using bacteria?
- (A) Bread from wheat flour only
- (B) Wine from grapes only
- (C) Paper from wood pulp
- (D) Cheese from milk
Show Answer
Answer: D – Bacteria ferment lactose in milk during cheese making, producing lactic acid.
Q59. Which statement about genetically modified bacteria producing insulin is correct?
- (A) Bacteria are given the human insulin gene and produce insulin as they grow
- (B) Bacteria digest insulin in the gut
- (C) Insulin is extracted from human pancreases only
- (D) Bacteria change into human cells
Show Answer
Answer: A – Recombinant bacteria express the inserted gene and make human insulin.
Q60. Which concern is raised about antibiotic resistance genes in genetically modified crops?
- (A) They improve crop taste
- (B) They might transfer to bacteria and increase resistance
- (C) They make crops need more water
- (D) They stop photosynthesis
Show Answer
Answer: B – Marker genes for antibiotic resistance could, in theory, spread to gut bacteria.
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