IGCSE Biology Practice Test 19 – 60 Questions with Answers (Cambridge 0610)
This full-syllabus test revisits every topic once more, so treat each section as a quick check of what you already know.
Characteristics and classification of living organisms
Q1. Which life process removes waste products of metabolism from an organism?
- (A) Nutrition in this context, when the other conditions are taken into account
- (B) Growth
- (C) Movement
- (D) Excretion
Show Answer
Answer: D – Excretion is the removal of toxic metabolic waste, such as urea and carbon dioxide, from the body.
Q2. Which organism belongs to the fungus kingdom?
- (A) Amoeba
- (B) Yeast
- (C) Bacterium
- (D) Alga
Show Answer
Answer: B – Yeast is a single-celled fungus that feeds saprotrophically and reproduces by budding.
Q3. Which feature is used to place an animal in the vertebrate group?
- (A) Jointed legs
- (B) A shell
- (C) A backbone
- (D) Six legs
Show Answer
Answer: C – Vertebrates have a backbone made of vertebrae protecting the spinal cord.
Organisation of the organism
Q4. Which level is formed when different tissues work together?
- (A) Organ
- (B) Cell
- (C) Organism
- (D) Population
Show Answer
Answer: A – An organ is a structure made of several tissues working together for a particular function.
Q5. Which cell structure contains the genetic material in an animal cell?
- (A) Nucleus
- (B) Ribosome
- (C) Vacuole
- (D) Cell membrane
Show Answer
Answer: A – The nucleus holds chromosomes made of DNA, which carry instructions for the cell.
Q6. Which specialised plant cell has no nucleus and forms a tube for water transport?
- (A) Guard cell
- (B) Palisade cell
- (C) Xylem vessel element
- (D) Root hair cell in this context, when the other conditions are taken into account
Show Answer
Answer: C – Xylem vessel elements lose their contents to form hollow tubes that carry water upwards.
Movement into and out of cells
Q7. Which process moves oxygen from the alveoli into the blood?
- (A) Active transport
- (B) Diffusion
- (C) Osmosis
- (D) Phagocytosis
Show Answer
Answer: B – Oxygen diffuses down its concentration gradient from air in the alveoli into capillary blood.
Q8. Which factor reduces the rate of osmosis into a cell?
- (A) A larger surface area in this context, when the other conditions are taken into account
- (B) A higher temperature
- (C) A thinner membrane
- (D) A smaller water potential gradient
Show Answer
Answer: D – A smaller difference in water potential means slower net movement of water by osmosis.
Q9. Which statement about partially permeable membranes is correct?
- (A) They allow all particles through
- (B) They block all particles
- (C) They allow some particles through but not others
- (D) They only allow large particles through in this context, when the other conditions are taken into account
Show Answer
Answer: C – Partially permeable membranes let small molecules such as water pass while blocking larger molecules.
Biological molecules
Q10. Which molecule is the monomer of a protein?
- (A) Glucose
- (B) Amino acid
- (C) Fatty acid in this context, when the other conditions are taken into account
- (D) Glycerol
Show Answer
Answer: B – Proteins are polymers built from amino acid monomers joined by peptide bonds.
Q11. Which food gives a blue-black colour with iodine solution?
- (A) Starch
- (B) Glucose
- (C) Protein
- (D) Fat
Show Answer
Answer: A – Iodine solution turns blue-black in the presence of starch.
Q12. Which statement about water is important for living organisms?
- (A) It is a poor solvent
- (B) It has a low specific heat capacity in this context, when the other conditions are taken into account
- (C) It cannot carry dissolved gases
- (D) It is a good solvent for many substances
Show Answer
Answer: D – Water dissolves many substances, allowing transport and chemical reactions in cells and blood.
Enzymes
Q13. Which enzyme in the small intestine breaks down fats into fatty acids and glycerol?
- (A) Amylase
- (B) Pepsin
- (C) Maltase
- (D) Lipase
Show Answer
Answer: D – Lipase, from the pancreas, digests lipids in the small intestine after bile has emulsified them.
Q14. Which condition denatures pepsin most quickly?
- (A) Strongly alkaline conditions
- (B) Acidic conditions around pH 2
- (C) A temperature of 37 degrees Celsius
- (D) A high substrate concentration
Show Answer
Answer: A – Pepsin works best in acid, so strongly alkaline conditions change its active site and denature it.
Q15. Which graph shape shows enzyme activity against temperature up to the optimum and beyond?
- (A) A straight line rising forever in this context, when the other conditions are taken into account
- (B) A rise to a peak, then a sharp fall
- (C) A flat line with no change
- (D) A fall, then a rise
Show Answer
Answer: B – Rate rises with kinetic energy to the optimum, then falls sharply as the enzyme denatures.
Plant nutrition
Q16. Which plant shows magnesium deficiency most clearly?
- (A) A plant with thick stems
- (B) A plant with extra flowers
- (C) A plant with yellow leaves between green veins
- (D) A plant with deep roots only in this context, when the other conditions are taken into account
Show Answer
Answer: C – Without magnesium, chlorophyll cannot form properly, so leaves turn yellow, often between veins.
Q17. Which experiment uses a variegated leaf to show that photosynthesis needs chlorophyll?
- (A) Covering a leaf with foil
- (B) Testing green and white areas separately for starch
- (C) Placing a plant in darkness in this context, when the other conditions are taken into account
- (D) Adding fertiliser to soil
Show Answer
Answer: B – Only the green, chlorophyll-containing areas test positive for starch after exposure to light.
Q18. Which limiting factor is most likely to restrict photosynthesis in a glasshouse at night?
- (A) Light intensity
- (B) Carbon dioxide concentration
- (C) Water supply
- (D) Temperature only
Show Answer
Answer: A – At night there is no light energy, so light is the factor that limits photosynthesis to zero.
Human nutrition
Q19. Which enzyme digests starch in the mouth?
- (A) Pepsin, an enzyme that works in the acid conditions of the stomach
- (B) Lipase
- (C) Amylase
- (D) Trypsin
Show Answer
Answer: C – Salivary amylase in saliva begins breaking starch down into smaller sugars in the mouth.
Q20. Which function does hydrochloric acid perform in the stomach?
- (A) It emulsifies fats
- (B) It absorbs amino acids in this context, when the other conditions are taken into account
- (C) It neutralises bile
- (D) It kills bacteria and provides the optimum pH for pepsin
Show Answer
Answer: D – Stomach acid kills many ingested pathogens and creates acidic conditions in which pepsin works best.
Q21. Which diet-related problem is caused by too little fibre in the diet?
- (A) Scurvy
- (B) Anaemia in this context, when the other conditions are taken into account
- (C) Constipation
- (D) Rickets
Show Answer
Answer: C – Fibre adds bulk and keeps food moving through the gut, so low fibre intake leads to constipation.
Transport in plants
Q22. Which environmental condition gives the lowest rate of transpiration?
- (A) Bright light
- (B) Windy conditions in this context, when the other conditions are taken into account
- (C) High temperature
- (D) Humid, still air
Show Answer
Answer: D – Humid, still air reduces the water vapour gradient, so less water diffuses out of the leaf.
Q23. Which tissue is found on the outside of a leaf and reduces water loss?
- (A) Mesophyll in this context, when the other conditions are taken into account
- (B) Epidermis with cuticle
- (C) Phloem
- (D) Cambium
Show Answer
Answer: B – The waxy cuticle over the epidermis limits evaporation from leaf surfaces.
Q24. In which direction does translocation move sucrose in spring when buds are growing?
- (A) From storage organs to growing buds
- (B) From buds to storage organs only in this context, when the other conditions are taken into account
- (C) From roots to leaves only
- (D) From flowers to roots only
Show Answer
Answer: A – Stored sucrose moves in phloem to sinks such as growing buds that need energy and materials.
Transport in animals
Q25. Which chamber receives deoxygenated blood from the body?
- (A) Right atrium
- (B) Left atrium
- (C) Left ventricle
- (D) Aorta
Show Answer
Answer: A – The vena cava delivers deoxygenated blood into the right atrium.
Q26. Which valve prevents backflow of blood from the right ventricle to the right atrium?
- (A) Bicuspid valve, which separates the left atrium from the left ventricle
- (B) Aortic valve
- (C) Pulmonary valve
- (D) Tricuspid valve
Show Answer
Answer: D – The tricuspid valve closes when the right ventricle contracts, stopping blood flowing back into the right atrium.
Q27. Which blood cell type engulfs pathogens?
- (A) Red blood cell
- (B) Platelet
- (C) Phagocyte
- (D) Plasma cell only
Show Answer
Answer: C – Phagocytes ingest and digest pathogens as part of the non-specific immune defence.
Diseases and immunity
Q28. Which disease is caused by a virus spread in droplets from coughs and sneezes?
- (A) Cholera
- (B) Influenza
- (C) Tuberculosis
- (D) Malaria
Show Answer
Answer: B – Influenza is a viral infection spread by droplets, unlike bacterial cholera and tuberculosis.
Q29. Which cells provide long-term protection after a first infection?
- (A) Platelets
- (B) Memory cells
- (C) Red blood cells
- (D) Guard cells
Show Answer
Answer: B – Memory lymphocytes remain after infection and allow a faster, stronger response on re-exposure.
Q30. Which hygiene measure best reduces transmission of diarrhoeal diseases?
- (A) Sharing towels
- (B) Eating unwashed food
- (C) Washing hands and treating drinking water
- (D) Storing raw and cooked food together in this context, when the other conditions are taken into account
Show Answer
Answer: C – Hand washing and safe water break faecal-oral transmission routes for many gut pathogens.
Gas exchange in humans
Q31. Which feature keeps the trachea open during breathing?
- (A) Smooth muscle only in this context, when the other conditions are taken into account
- (B) Mucus lining
- (C) Thin walls
- (D) Rings of cartilage
Show Answer
Answer: D – C-shaped cartilage rings support the trachea and prevent it collapsing as air moves in and out.
Q32. Which process moves air into the lungs during inhalation?
- (A) Chest volume increases, so air pressure inside falls below outside pressure
- (B) Chest volume decreases, forcing air in
- (C) Diaphragm relaxes and pushes air in
- (D) Ribs move down and in
Show Answer
Answer: A – Increased chest volume lowers internal pressure, so air flows in from higher outside pressure.
Q33. Which gas diffuses from alveolar air into capillary blood?
- (A) Carbon dioxide only
- (B) Nitrogen only
- (C) Water vapour only
- (D) Oxygen
Show Answer
Answer: D – Oxygen is at higher concentration in the alveoli than in incoming blood, so it diffuses into the blood.
Respiration
Q34. Which statement about respiration is correct?
- (A) It only occurs in animals
- (B) It stores energy in glucose
- (C) It releases energy from glucose in all living cells
- (D) It only occurs in daylight
Show Answer
Answer: C – All living cells respire to release energy for their processes, day and night.
Q35. Which test shows that air breathed out contains carbon dioxide?
- (A) Limewater turns milky
- (B) Iodine turns blue-black
- (C) Benedict’s turns brick-red
- (D) Biuret turns purple
Show Answer
Answer: A – Carbon dioxide reacts with limewater to form a milky precipitate of calcium carbonate.
Q36. Which activity relies most on anaerobic respiration in muscle?
- (A) Slow walking
- (B) A short all-out sprint
- (C) Sleeping
- (D) Gentle stretching
Show Answer
Answer: B – A sprint demands energy faster than oxygen can be supplied, so muscles respire anaerobically.
Excretion in humans
Q37. Which structure carries urine from the kidney to the bladder?
- (A) Ureter
- (B) Urethra
- (C) Renal artery
- (D) Collecting duct
Show Answer
Answer: A – Each ureter carries urine downwards from its kidney to the bladder for storage.
Q38. Which substance is reabsorbed from the kidney tubule back into the blood?
- (A) Urea only
- (B) Glucose and water
- (C) Carbon dioxide
- (D) Excess urea only
Show Answer
Answer: B – Glucose is fully reabsorbed and water is reabsorbed as needed, while urea largely remains for excretion.
Coordination and response
Q39. Which action is an example of a reflex?
- (A) Choosing a book to read
- (B) Solving a puzzle
- (C) Writing an essay
- (D) Blinking when an object approaches the eye
Show Answer
Answer: D – Blinking to protect the eye is rapid, automatic and does not involve conscious decision-making.
Q40. Which hormone controls the menstrual cycle together with oestrogen?
- (A) Insulin
- (B) Adrenaline
- (C) Progesterone
- (D) ADH
Show Answer
Answer: C – Progesterone maintains the uterus lining after ovulation, working alongside oestrogen in the cycle.
Drugs
Q41. Which statement about heroin is correct?
- (A) It is a legal medicine for all uses
- (B) It improves lung capacity
- (C) It is a powerful depressant that can cause overdose
- (D) It has no withdrawal effects
Show Answer
Answer: C – Heroin depresses the nervous system and breathing, and overdose can be fatal.
Q42. Which effect does nicotine have on blood vessels?
- (A) It narrows small arteries, raising blood pressure
- (B) It widens all vessels permanently
- (C) It removes cholesterol from blood
- (D) It increases oxygen carriage
Show Answer
Answer: A – Nicotine constricts small arteries, which raises blood pressure and strains the heart.
Reproduction
Q43. Which type of reproduction involves two parents and fusion of gametes?
- (A) Budding
- (B) Sexual reproduction
- (C) Binary fission
- (D) Vegetative propagation
Show Answer
Answer: B – Sexual reproduction combines gametes from two parents, producing varied offspring.
Q44. Which structure protects and nourishes a developing fetus in mammals?
- (A) Ovary
- (B) Oviduct
- (C) Cervix alone
- (D) Placenta and uterus
Show Answer
Answer: D – The placenta exchanges nutrients and wastes, while the uterus houses and protects the fetus.
Q45. Which advantage does seed dispersal give a plant?
- (A) It prevents photosynthesis
- (B) It reduces competition between parent and offspring
- (C) It stops pollination
- (D) It increases self-fertilisation
Show Answer
Answer: B – Dispersal spreads offspring away from the parent, reducing competition for light, water and nutrients.
Inheritance
Q46. Which term describes an organism with two identical alleles for a gene?
- (A) Homozygous
- (B) Heterozygous
- (C) Dominant
- (D) Recessive
Show Answer
Answer: A – Homozygous means both alleles for a gene are the same, for example AA or aa.
Q47. What is meant by the phenotype of an organism?
- (A) The alleles it has for a particular characteristic, inherited from both parents
- (B) Pyramid of numbers
- (C) Carbon cycle diagram
- (D) The observable characteristics of an organism
Show Answer
Answer: D – Phenotype is what an organism looks like or how it behaves, produced by its genotype and the environment.
Q48. Which process produces genetically different gametes?
- (A) Mitosis
- (B) Cloning
- (C) Meiosis with random assortment
- (D) Binary fission
Show Answer
Answer: C – Meiosis shuffles chromosomes and alleles, so each gamete carries a different combination.
Variation and selection
Q49. Which example of variation is mainly environmental?
- (A) Eye colour
- (B) Blood group
- (C) Natural hair colour
- (D) A scar gained from an accident
Show Answer
Answer: D – A scar is acquired from the environment during life and is not inherited from parents.
Q50. What is the source of new alleles in a population?
- (A) Selective breeding by humans choosing parents with desired characteristics over generations
- (B) It requires no variation
- (C) Mutation of DNA
- (D) It makes every individual identical
Show Answer
Answer: C – A mutation changes the DNA sequence of a gene, creating a new allele that can be inherited.
Q51. Which risk can arise from selective breeding for a single trait?
- (A) Increased genetic diversity
- (B) Reduced genetic diversity and inbreeding problems
- (C) Faster mutation rates
- (D) Loss of all variation in one generation
Show Answer
Answer: B – Breeding closely related individuals for one trait reduces diversity and can increase inherited disorders.
Organisms and their environment
Q52. Which pyramid shows the number of organisms at each trophic level?
- (A) Pyramid of numbers
- (B) Pyramid of energy only
- (C) Pyramid of biomass only
- (D) Pyramid of carbon
Show Answer
Answer: A – A pyramid of numbers counts organisms at each level, though its shape can be inverted in some food chains.
Q53. Which process releases nutrients from dead organisms back into the soil?
- (A) Photosynthesis
- (B) Decomposition
- (C) Transpiration
- (D) Pollination
Show Answer
Answer: B – Decomposers break down dead material, returning mineral ions to the soil for plant uptake.
Q54. Which abiotic factor most affects where a plant species can grow?
- (A) Competition
- (B) Predation
- (C) Disease
- (D) Light intensity and soil conditions
Show Answer
Answer: D – Light and soil factors such as pH and water availability limit which plants survive in a habitat.
Human influences on ecosystems
Q55. Which consequence of global warming threatens low-lying coastal communities?
- (A) Rising sea levels
- (B) Colder winters everywhere
- (C) Less rainfall everywhere
- (D) Thicker ice caps
Show Answer
Answer: A – Melting ice and thermal expansion raise sea levels, increasing flooding of coastal areas.
Q56. Which pollutant causes acid rain when released from burning fossil fuels?
- (A) Carbon dioxide only
- (B) Methane
- (C) Sulfur dioxide
- (D) Oxygen
Show Answer
Answer: C – Sulfur dioxide dissolves in rainwater to form acidic rain that damages forests and lakes.
Q57. Which action reduces a person’s carbon footprint?
- (A) Flying more often
- (B) Leaving lights on all day
- (C) Using public transport and insulating the home
- (D) Burning more coal for heating
Show Answer
Answer: C – Efficient transport and home insulation cut fossil fuel use and therefore carbon dioxide emissions.
Biotechnology and genetic modification
Q58. Which organism is commonly used to produce penicillin in a fermenter?
- (A) A fungus
- (B) A virus
- (C) A green plant
- (D) An animal cell
Show Answer
Answer: A – Penicillin is produced by the fungus Penicillium grown under controlled conditions in fermenters.
Q59. Which step is needed before a gene can be inserted into bacteria?
- (A) Heating the bacteria to boiling
- (B) Removing all plasmids permanently
- (C) Growing bacteria without nutrients
- (D) Cutting the gene and plasmid with the same restriction enzyme
Show Answer
Answer: D – Matching sticky ends allow the gene to join with the plasmid, which is then taken up by bacteria.
Q60. Which benefit of genetic modification is relevant to vitamin A deficiency?
- (A) Crops that grow without water
- (B) Golden rice with added beta-carotene
- (C) Crops that need no sunlight
- (D) Rice that produces insulin
Show Answer
Answer: B – Golden rice is modified to produce beta-carotene, which the body converts to vitamin A.
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