IGCSE Biology Practice Test 3 – 60 Questions with Answers (Cambridge 0610)
This test mixes data questions with core knowledge, so read each stem carefully before choosing an answer.
Characteristics and classification of living organisms
Q1. Which of these is NOT a characteristic of all living organisms?
- (A) Photosynthesis
- (B) Respiration in every living cell
- (C) Movement
- (D) Growth
Show Answer
Answer: A – Only some organisms photosynthesise, while all respire, move and grow.
Q2. Which kingdom contains organisms with chitin cell walls that feed by external digestion?
- (A) Plants
- (B) Animals
- (C) Fungi
- (D) Protoctists
Show Answer
Answer: C – Fungi secrete enzymes externally and absorb the digested nutrients.
Q3. A dichotomous key asks: “Has wings? Yes → go to 2, No → go to 3.” What is the purpose of such a key?
- (A) To name a new species
- (B) To identify an organism step by step
- (C) To count population size
- (D) To measure growth rate
Show Answer
Answer: B – Each paired statement narrows down the identity of the specimen.
Organisation of the organism
Q4. Which tissue is specialised for contraction?
- (A) Epithelial tissue
- (B) Nervous tissue
- (C) Xylem tissue
- (D) Muscle tissue
Show Answer
Answer: D – Muscle tissue contracts to produce movement.
Q5. Which organ system transports hormones around the body?
- (A) Nervous system
- (B) Digestive system
- (C) Respiratory system
- (D) Circulatory system
Show Answer
Answer: D – Hormones travel in blood plasma to target organs.
Q6. Which cell structure controls the activities of the cell?
- (A) Ribosome
- (B) Nucleus
- (C) Vacuole
- (D) Mitochondrion
Show Answer
Answer: B – The nucleus contains genetic material that directs cell activities.
Movement into and out of cells
Q7. A dialysis bag containing starch solution is placed in water. Starch stays inside but water enters. What does this show?
- (A) The bag is partially permeable
- (B) Starch is actively transported
- (C) Water is pumped by the bag
- (D) Starch dissolves in water
Show Answer
Answer: A – Small water molecules pass through, while large starch molecules cannot.
Q8. Which change would slow osmosis into a cell?
- (A) A larger surface area
- (B) A thinner membrane
- (C) A smaller difference in water concentration
- (D) A higher temperature
Show Answer
Answer: C – Osmosis rate depends on the water potential gradient across the membrane.
Q9. How does oxygen enter a red blood cell in the lungs?
- (A) By active transport against a concentration gradient
- (B) By diffusion down a concentration gradient
- (C) By osmosis through the vacuole
- (D) By phagocytosis of air bubbles
Show Answer
Answer: B – Oxygen is at a higher concentration in the alveoli than in the blood, so it diffuses into red blood cells.
Biological molecules
Q10. Which statement about proteins is correct?
- (A) They are made from amino acids joined together
- (B) They are made from fatty acids and glycerol in the liver
- (C) They are made from glucose units only
- (D) They are made from nucleotides only
Show Answer
Answer: A – Proteins are polymers of amino acids linked by peptide bonds.
Q11. A sample gives a purple colour with biuret solution. What is present?
- (A) Starch
- (B) Glucose
- (C) Protein
- (D) Vitamin C
Show Answer
Answer: C – Biuret reagent turns purple in the presence of protein.
Q12. Which carbohydrate is the storage molecule in plants?
- (A) Glucose
- (B) Cellulose
- (C) Sucrose
- (D) Starch
Show Answer
Answer: D – Plants store excess glucose as insoluble starch grains.
Enzymes
Q13. In an experiment, the rate of reaction stops rising when more substrate is added. What limits the rate?
- (A) Too much water present
- (B) Too little product formed during the reaction
- (C) All active sites are occupied
- (D) The enzyme has dissolved
Show Answer
Answer: C – Once saturated, extra substrate cannot increase the rate further.
Q14. Lipase breaks down fats into:
- (A) Amino acids
- (B) Fatty acids and glycerol
- (C) Glucose units
- (D) Peptides only
Show Answer
Answer: B – Lipase hydrolyses fats to fatty acids and glycerol.
Q15. Which factor does NOT affect enzyme activity?
- (A) Temperature
- (B) pH
- (C) Substrate concentration in the reaction mixture
- (D) Colour of the reaction tube
Show Answer
Answer: D – Tube colour has no effect on enzyme shape or collision rates.
Plant nutrition
Q16. Which limiting factor is most likely to restrict photosynthesis on a cloudy winter day?
- (A) Light intensity
- (B) Carbon dioxide concentration
- (C) Soil nitrate level
- (D) Leaf size
Show Answer
Answer: A – Low light limits the light-dependent stage of photosynthesis.
Q17. How does a leaf’s thin shape help photosynthesis?
- (A) It reduces water loss completely
- (B) It gives a large surface area for light absorption
- (C) It stores starch in the veins
- (D) It prevents gas exchange
Show Answer
Answer: B – A large, thin blade captures light efficiently and shortens diffusion distances.
Q18. Which word equation describes photosynthesis?
- (A) Carbon dioxide + water → glucose + oxygen
- (B) Glucose + oxygen → carbon dioxide + water
- (C) Glucose → ethanol + carbon dioxide
- (D) Oxygen + water → glucose + carbon dioxide
Show Answer
Answer: A – Photosynthesis builds glucose from carbon dioxide and water using light energy.
Human nutrition
Q19. What is the role of hydrochloric acid in the stomach?
- (A) To emulsify fats
- (B) To absorb amino acids
- (C) To kill pathogens and provide the optimum pH for pepsin
- (D) To neutralise bile
Show Answer
Answer: C – Acid kills microbes and creates the low pH pepsin needs.
Q20. After a meal rich in starch, which organ releases amylase into the small intestine?
- (A) Liver
- (B) Gall bladder
- (C) Stomach lining
- (D) Pancreas
Show Answer
Answer: D – Pancreatic juice contains amylase, protease and lipase.
Transport in plants
Q21. Which statement about xylem is correct?
- (A) It transports sugars in both directions
- (B) It is made of living cells with cytoplasm
- (C) It carries water only at night
- (D) It consists of dead, hollow vessels
Show Answer
Answer: D – Xylem vessels are dead tubes that allow uninterrupted water flow.
Q22. A leafy shoot loses mass fastest in hot, dry, windy conditions. Why?
- (A) Photosynthesis stops in heat
- (B) Roots absorb less water
- (C) Transpiration rate is highest
- (D) Stomata remain closed all day
Show Answer
Answer: C – Heat, dry air and wind all steepen the water vapour gradient from leaves.
Transport in animals
Q23. Which vessel has valves and thin walls?
- (A) Vein
- (B) Artery
- (C) Capillary
- (D) Aorta
Show Answer
Answer: A – Veins carry low-pressure blood, so valves prevent backflow.
Q24. What is the function of platelets?
- (A) Carrying oxygen
- (B) Forming blood clots
- (C) Producing antibodies
- (D) Transporting hormones
Show Answer
Answer: B – Platelets trigger clotting to seal wounds and prevent blood loss.
Diseases and immunity
Q25. Which pathogen is responsible for AIDS?
- (A) A bacterium
- (B) A fungus
- (C) A protoctist
- (D) A virus
Show Answer
Answer: D – HIV is a virus that attacks cells of the immune system.
Q26. How do phagocytes destroy pathogens?
- (A) By producing antibodies only in the blood
- (B) By blocking blood vessels
- (C) By engulfing and digesting them
- (D) By raising body temperature
Show Answer
Answer: C – Phagocytes surround pathogens and digest them with enzymes.
Q27. Which is an example of active immunity?
- (A) Immunity after vaccination
- (B) Antibodies passed in breast milk
- (C) Antibodies injected during treatment
- (D) Antibodies crossing the placenta
Show Answer
Answer: A – Vaccination stimulates the person’s own immune system to make memory cells.
Gas exchange in humans
Q28. Which change occurs in the thorax during inhalation?
- (A) Volume decreases and pressure rises
- (B) Volume increases and pressure falls
- (C) Volume and pressure stay constant
- (D) Volume falls and pressure falls
Show Answer
Answer: B – Larger chest volume lowers air pressure, so air flows in.
Q29. What is the function of goblet cells in the airways?
- (A) To produce mucus that traps dust and microbes
- (B) To carry oxygen in blood
- (C) To contract the diaphragm
- (D) To absorb carbon dioxide
Show Answer
Answer: A – Mucus traps particles, which cilia then sweep upwards.
Q30. A student measures breathing rate before and after running. What is the expected result?
- (A) Rate falls because lungs fill with oxygen
- (B) Rate rises and never returns to resting level
- (C) Rate stays exactly the same
- (D) Rate rises then returns to resting level
Show Answer
Answer: D – Breathing rate rises during exercise and falls back to resting level afterwards.
Respiration
Q31. Which organelle is most abundant in a muscle cell that respires rapidly?
- (A) Chloroplast in green plant cells
- (B) Mitochondrion
- (C) Vacuole
- (D) Ribosome
Show Answer
Answer: B – Many mitochondria supply the energy active muscle cells need.
Q32. What is the energy currency released by respiration used for?
- (A) Photosynthesis only
- (B) Digestion only
- (C) Muscle contraction, active transport and cell division
- (D) Storage as starch only
Show Answer
Answer: C – Respiration energy powers many cellular processes.
Q33. During vigorous exercise, oxygen debt is repaid by:
- (A) Holding the breath
- (B) Continued fast breathing to oxidise lactate
- (C) Drinking water only
- (D) Stopping respiration completely
Show Answer
Answer: B – Extra oxygen after exercise breaks down accumulated lactate.
Excretion in humans
Q34. What is the function of the loop of Henle in the kidney?
- (A) Filtration of blood under high pressure in the glomerulus and capsule
- (B) Storage of urine
- (C) Reabsorption of water into the blood
- (D) Production of urea
Show Answer
Answer: C – Water is reabsorbed from the tubule fluid as it passes through the loop of Henle back into the blood.
Q35. Why is the liver important in excretion?
- (A) It filters blood directly into urine
- (B) It stores excess water
- (C) It produces bile pigments only
- (D) It breaks down excess amino acids to urea
Show Answer
Answer: D – Deamination in the liver converts amino acids to urea for excretion.
Q36. Which substance is selectively reabsorbed in the proximal tubule?
- (A) All glucose and amino acids
- (B) All urea and salts
- (C) All water and no solutes at all
- (D) All proteins and cells
Show Answer
Answer: A – Useful small molecules are fully reabsorbed back into the blood.
Coordination and response
Q37. Which part of the eye focuses light onto the retina?
- (A) Iris
- (B) Lens
- (C) Sclera
- (D) Optic nerve
Show Answer
Answer: B – The lens changes shape to focus light sharply on the retina.
Q38. A reflex action is fast because:
- (A) It uses hormones instead of nerves
- (B) It involves conscious decision making
- (C) It uses many relay neurones in the brain
- (D) It has a short pathway through the spinal cord
Show Answer
Answer: D – A short spinal pathway avoids the slower conscious route.
Q39. Which hormone prepares the body for a “fight or flight” response?
- (A) Adrenaline
- (B) Insulin
- (C) Thyroxine from the thyroid gland
- (D) Oestrogen
Show Answer
Answer: A – Adrenaline raises heart rate and blood glucose for rapid action.
Drugs
Q40. Which drug is a stimulant found in tea and coffee?
- (A) Heroin
- (B) Alcohol
- (C) Caffeine
- (D) Morphine
Show Answer
Answer: C – Caffeine stimulates the nervous system and increases alertness.
Q41. What is a depressant drug?
- (A) A drug that slows down brain activity
- (B) A drug that speeds up the heart permanently
- (C) A drug that cures all infections
- (D) A drug that replaces vitamins
Show Answer
Answer: A – Depressants such as alcohol slow reactions and judgement.
Q42. Smoking during pregnancy is discouraged mainly because:
- (A) It increases appetite greatly
- (B) It improves blood flow to the fetus
- (C) Carbon monoxide and nicotine can harm fetal growth
- (D) It prevents morning sickness
Show Answer
Answer: C – Reduced oxygen delivery can restrict growth and lower birth mass.
Reproduction
Q43. Which part of the flower receives pollen during pollination?
- (A) Ovary
- (B) Anther
- (C) Filament
- (D) Stigma
Show Answer
Answer: D – Pollen lands on the sticky stigma before growing a pollen tube.
Q44. What is fertilisation in flowering plants?
- (A) Transfer of pollen to a stigma
- (B) Fusion of male and female gamete nuclei
- (C) Growth of a seed into a plant
- (D) Opening of a flower bud
Show Answer
Answer: B – Fertilisation forms a zygote when the gamete nuclei fuse.
Q45. Which advantage does sexual reproduction give a species?
- (A) Offspring are identical to parents
- (B) Reproduction is faster than asexual methods in plants
- (C) Genetic variation helps adaptation to change
- (D) Only one parent is ever needed
Show Answer
Answer: C – Variation from meiosis and fertilisation aids survival in changing conditions.
Inheritance
Q46. Which term describes the genetic makeup of an organism?
- (A) Phenotype
- (B) Genotype
- (C) Allele
- (D) Chromosome
Show Answer
Answer: B – Genotype is the combination of alleles an organism carries.
Q47. A cross between two heterozygous plants (Aa x Aa) gives what ratio of dominant to recessive phenotypes?
- (A) 3:1
- (B) 1:1
- (C) 1:2:1
- (D) 9:3:3:1
Show Answer
Answer: A – The Punnett square gives three dominant phenotypes to one recessive.
Q48. When does a child show a recessive genetic disorder such as cystic fibrosis?
- (A) When one parent passes on a dominant allele
- (B) When the child eats a special diet
- (C) When only the mother carries the recessive allele
- (D) When the child inherits a recessive allele from both parents
Show Answer
Answer: D – A recessive disorder is only expressed when both copies of the gene carry the recessive allele.
Variation and selection
Q49. Which example shows variation caused by genes only?
- (A) Body mass, which depends on both inherited factors and diet and activity levels
- (B) Height
- (C) Skin colour affected by sunlight
- (D) Blood group
Show Answer
Answer: D – Blood group is determined by the alleles inherited from the parents and is not changed by the environment.
Q50. What is meant by natural selection?
- (A) Organisms better adapted to their environment survive and reproduce more successfully
- (B) Humans deliberately choosing parent organisms with useful features and breeding from them over many generations
- (C) Random mutation in wild populations
- (D) Cloning by tissue culture only
Show Answer
Answer: A – Better-adapted individuals are more likely to survive and pass their alleles to the next generation.
Q51. Why might a new species form after populations become isolated?
- (A) Isolated groups stop mutating
- (B) Isolated groups share all genes freely
- (C) Different selection pressures lead to reproductive isolation
- (D) Isolated groups lose all variation
Show Answer
Answer: C – Diverging populations may eventually be unable to interbreed.
Organisms and their environment
Q52. Which organism is a secondary consumer in a grass → rabbit → fox food chain?
- (A) Grass
- (B) Fox
- (C) Rabbit
- (D) Soil bacteria
Show Answer
Answer: B – The fox eats the primary consumer, so it is a secondary consumer.
Q53. In the nitrogen cycle, which bacteria convert ammonium compounds to nitrates?
- (A) Denitrifying bacteria
- (B) Nitrogen-fixing bacteria
- (C) Nitrifying bacteria
- (D) Decomposer fungi
Show Answer
Answer: C – Nitrifying bacteria carry out nitrification in the soil.
Q54. Why is a quadrat used in ecological sampling?
- (A) To catch fast animals
- (B) To estimate population size and distribution
- (C) To measure wind speed
- (D) To test soil pH directly
Show Answer
Answer: B – Quadrats give standardised samples for estimating abundance.
Human influences on ecosystems
Q55. Which measure helps reduce deforestation?
- (A) Clearing large areas of forest to create farmland for growing crops and grazing animals
- (B) Burning wood for fuel
- (C) Building roads through forests
- (D) Replanting trees and protecting forest areas
Show Answer
Answer: D – Replanting replaces felled trees and protected areas keep forest habitats intact for wildlife.
Q56. What is the main cause of the enhanced greenhouse effect?
- (A) Rising carbon dioxide and methane from human activity
- (B) Increased oxygen from plants
- (C) Decreased rainfall worldwide
- (D) Cooling of the oceans
Show Answer
Answer: A – Extra greenhouse gases trap more heat in the atmosphere.
Q57. Which gas is released by burning fossil fuels and contributes to global warming?
- (A) Carbon dioxide
- (B) Oxygen, which is released by plants during photosynthesis in daylight
- (C) Nitrogen
- (D) Ozone
Show Answer
Answer: A – Burning coal, oil and gas releases carbon dioxide, a greenhouse gas that traps heat in the atmosphere.
Biotechnology and genetic modification
Q58. Which organism is used in bread making to release carbon dioxide?
- (A) Lactobacillus bacteria
- (B) Penicillium fungus
- (C) Rhizobium bacteria
- (D) Yeast
Show Answer
Answer: D – Yeast respires anaerobically, producing carbon dioxide that raises dough.
Q59. What is a plasmid in genetic engineering?
- (A) A human chromosome
- (B) A small circular DNA molecule in bacteria
- (C) An enzyme that cuts DNA
- (D) A type of fermenter vessel
Show Answer
Answer: B – Plasmids act as vectors carrying foreign genes into bacteria.
Q60. Which product is made using genetically modified bacteria?
- (A) Bread dough
- (B) Yoghurt culture
- (C) Human insulin
- (D) Cheese curd
Show Answer
Answer: C – Bacteria carrying the human insulin gene produce insulin in fermenters.
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