IGCSE Biology Practice Test 15 – 60 Questions with Answers (Cambridge 0610)
This final test in the set brings together every syllabus topic once more, so use it as a full check before exam practice.
Characteristics and classification of living organisms
Q1. Which characteristic is shown when a plant root grows downwards in response to gravity?
- (A) Excretion
- (B) Nutrition
- (C) Sensitivity
- (D) Respiration
Show Answer
Answer: C – Sensitivity includes responses to stimuli such as gravity, light and touch.
Q2. Which organism is a protoctist?
- (A) A yeast cell, a single-celled fungus used in baking
- (B) A moss plant
- (C) A mushroom
- (D) Amoeba, a single-celled organism with a nucleus
Show Answer
Answer: D – Protoctists are mostly single-celled eukaryotes, and Amoeba is a classic example, while yeast is a fungus.
Organisation of the organism
Q3. Which cell is specialised for carrying water in plants?
- (A) Guard cell
- (B) Palisade cell
- (C) Root hair cell, which absorbs water from soil
- (D) Xylem vessel cell
Show Answer
Answer: D – Xylem vessel cells are long, hollow and dead, forming tubes that carry water upwards.
Q4. Which tissue type covers the surfaces of organs in animals?
- (A) Muscle tissue
- (B) Epithelial tissue
- (C) Nervous tissue
- (D) Connective tissue
Show Answer
Answer: B – Epithelial tissue forms protective layers on outer and inner surfaces, such as skin and gut lining.
Movement into and out of cells
Q5. In which situation does active transport occur in the human gut?
- (A) Glucose is absorbed from the ileum into blood against a concentration gradient
- (B) Water moves into the blood by osmosis
- (C) Oxygen diffuses into gut cells
- (D) Carbon dioxide diffuses out of gut cells into the blood during respiration in the tissues
Show Answer
Answer: A – When blood glucose is already high, further uptake needs energy, so active transport is used.
Q6. A potato strip gains mass in pure water but loses mass in a strong sugar solution. What explains both results?
- (A) Active transport of sugar into the cells from the surrounding solution
- (B) Diffusion of starch out of the cells
- (C) Osmosis: water enters in pure water and leaves in the sugar solution
- (D) Respiration using up the potato tissue
Show Answer
Answer: C – Water moves by osmosis towards the more concentrated solution, so the strip swells in water and shrinks in sugar solution.
Biological molecules
Q7. Which simple sugar is the main product of photosynthesis?
- (A) Glucose
- (B) Maltose
- (C) Lactose
- (D) Sucrose only
Show Answer
Answer: A – Photosynthesis first produces glucose, which the plant may convert to starch, sucrose or other substances.
Q8. Which statement correctly describes the structure of DNA?
- (A) A single chain of amino acids
- (B) A chain of fatty acids and glycerol forming a fat molecule
- (C) A double helix of nucleotides with base pairing
- (D) A branched chain of glucose units
Show Answer
Answer: C – DNA consists of two strands of nucleotides wound into a helix, with adenine pairing with thymine and cytosine with guanine.
Q9. Which nutrient provides the body with amino acids for growth and repair?
- (A) Fat
- (B) Vitamin C
- (C) Water
- (D) Protein
Show Answer
Answer: D – Dietary protein is digested to amino acids, which cells use to build new proteins.
Enzymes
Q10. An enzyme and its substrate are mixed, and the reaction rate is measured. Adding more enzyme increases the rate. Why?
- (A) The substrate becomes more concentrated in the mixture over time
- (B) More active sites are available for substrate molecules
- (C) The temperature rises automatically
- (D) The pH changes to the optimum
Show Answer
Answer: B – With more enzyme molecules, more substrate can bind at once, so the overall rate rises.
Q11. Which enzyme is present in washing powder to break down protein stains, and why does it work in warm water?
- (A) Lipase, because it works best when cold
- (B) Protease, because warm water is near its optimum temperature
- (C) Amylase, because it digests starch stains only
- (D) Catalase, because it breaks down hydrogen peroxide in cells
Show Answer
Answer: B – Biological washing powders contain proteases that digest protein stains, working fastest at moderate temperatures before denaturing.
Q12. The active site of an enzyme is best described as which of the following?
- (A) The region where the substrate binds and the reaction occurs
- (B) The part of the enzyme that is used up in the reaction completely
- (C) The product formed by the reaction
- (D) The whole surface of the enzyme molecule
Show Answer
Answer: A – The active site has a shape complementary to the substrate, allowing a temporary enzyme-substrate complex to form.
Plant nutrition
Q13. Which process in a leaf uses light energy to split water molecules?
- (A) Respiration
- (B) Transpiration
- (C) The light-dependent stage of photosynthesis
- (D) Active transport in the phloem, moving sugars
Show Answer
Answer: C – In the light-dependent reactions, water is split to release oxygen, and energy is captured for making glucose.
Q14. A plant with nitrate deficiency is most likely to show which symptom?
- (A) Yellow leaves only in bright light conditions
- (B) Thick, dark green leaves
- (C) Rapid growth with weak stems
- (D) Poor growth and pale, yellowish leaves
Show Answer
Answer: D – Without nitrates the plant cannot make enough protein, so growth is stunted and leaves become pale.
Q15. Why is chlorophyll important for photosynthesis?
- (A) It stores glucose as starch in the chloroplast
- (B) It carries water to the leaf
- (C) It opens the stomata
- (D) It absorbs light energy for the reactions
Show Answer
Answer: D – Chlorophyll in chloroplasts traps light energy, which drives the synthesis of glucose.
Human nutrition
Q16. Which organ produces trypsin and lipase for digestion in the small intestine?
- (A) Liver
- (B) Pancreas
- (C) Stomach
- (D) Gall bladder
Show Answer
Answer: B – The pancreas secretes digestive enzymes, including trypsin and lipase, into the duodenum.
Q17. What is the main function of fibre in the diet?
- (A) To add bulk and help food move through the gut, preventing constipation
- (B) To provide the main energy source for the body during hard activity every day
- (C) To build new muscle tissue
- (D) To carry oxygen in the blood
Show Answer
Answer: A – Fibre is indigestible plant material that keeps the gut contents moving and supports regular bowel movements.
Q18. A balanced diet for a teenager differs from that for a small child mainly because of which factor?
- (A) Teenagers need no vitamins at all in their diet, unlike children
- (B) Children need no protein
- (C) Energy and nutrient needs change with age, size and activity
- (D) Teenagers need only fats
Show Answer
Answer: C – Requirements for energy, protein and minerals vary with growth rate, body size and activity level.
Transport in plants
Q19. Which adaptation helps a root hair cell absorb water efficiently?
- (A) A long, thin extension giving a large surface area
- (B) A thick waterproof cuticle
- (C) A large number of chloroplasts
- (D) A rigid cell wall with no permeability to water at all
Show Answer
Answer: A – The hair-like extension greatly increases surface area for osmosis, and the cell has no chloroplasts.
Q20. What is the transpiration stream?
- (A) The flow of sugars in the phloem
- (B) The flow of water vapour out of stomata only, not through the xylem at all
- (C) The continuous flow of water from roots, through xylem, to leaves
- (D) The flow of mineral ions in the soil
Show Answer
Answer: C – Water absorbed by roots moves up the xylem to the leaves, where much of it is lost by transpiration, pulling more water up.
Q21. A potometer measures water uptake by a leafy shoot. If the shoot is placed in bright light, what happens to the bubble movement?
- (A) The bubble stops moving
- (B) The bubble moves backwards, away from the shoot, as water is lost
- (C) The bubble moves more slowly
- (D) The bubble moves faster, showing greater water uptake
Show Answer
Answer: D – Bright light increases transpiration, so water is taken up faster and the air bubble moves more quickly along the capillary.
Transport in animals
Q22. Which sequence shows the correct path of blood through the heart, starting at the vena cava?
- (A) Right atrium, left ventricle, lungs, left atrium, right ventricle
- (B) Right atrium, right ventricle, lungs, left atrium, left ventricle
- (C) Left atrium, left ventricle, lungs, right atrium, right ventricle
- (D) Right ventricle, right atrium, lungs, left ventricle, left atrium
Show Answer
Answer: B – Deoxygenated blood enters the right side, goes to the lungs, returns to the left side, and is then pumped around the body.
Q23. Why is blood in the pulmonary artery deoxygenated even though it is an artery?
- (A) It has passed through the liver
- (B) It is travelling from the heart to the lungs to collect oxygen
- (C) It has lost oxygen in the muscles
- (D) It contains no red blood cells
Show Answer
Answer: B – Arteries carry blood away from the heart, and the pulmonary artery carries deoxygenated blood towards the lungs for oxygenation.
Q24. Which component of blood transports dissolved glucose, amino acids and hormones?
- (A) Plasma
- (B) Red blood cells
- (C) White blood cells
- (D) Platelets
Show Answer
Answer: A – Plasma is the liquid part of blood and carries dissolved nutrients, hormones, urea and other substances.
Diseases and immunity
Q25. Which method of controlling disease spread involves killing pathogens on surfaces and instruments?
- (A) Vaccination
- (B) Quarantine only, isolating infected patients
- (C) Sterilisation and disinfection
- (D) Passive immunity
Show Answer
Answer: C – Cleaning, disinfecting and sterilising remove or kill pathogens, reducing the chance of transmission.
Q26. A person recovers from measles and is then immune for life. Which cells provide this long-term immunity?
- (A) Red blood cells
- (B) Platelets
- (C) Muscle cells
- (D) Memory cells
Show Answer
Answer: D – Memory lymphocytes formed during the first infection respond rapidly if the same pathogen is encountered again.
Q27. Which statement about the immune response is correct?
- (A) All pathogens are destroyed by stomach acid alone
- (B) Antibodies are made by red blood cells
- (C) Phagocytes produce antibodies
- (D) Lymphocytes produce antibodies specific to an antigen
Show Answer
Answer: D – Each lymphocyte makes one type of antibody, which fits the antigen of a particular pathogen.
Gas exchange in humans
Q28. Which feature of the lungs increases the rate of diffusion of oxygen into the blood?
- (A) A thick wall around each alveolus
- (B) A rich capillary network around each alveolus
- (C) A dry inner surface
- (D) A single large air sac
Show Answer
Answer: B – Dense capillaries keep blood flowing past alveoli, maintaining a steep oxygen gradient for diffusion.
Q29. During vigorous exercise, which change in breathing is observed?
- (A) Breathing becomes deeper and faster
- (B) Breathing stops between breaths
- (C) Breathing becomes shallower and slower
- (D) Only the rate changes, not the depth
Show Answer
Answer: A – Deeper, faster breathing brings in more oxygen and removes carbon dioxide more quickly to meet muscle demand.
Q30. The diaphragm and intercostal muscles work together during inhalation to do what?
- (A) Decrease the volume of the thorax
- (B) Compress the lungs directly
- (C) Increase the volume of the thorax and lower air pressure inside
- (D) Close the trachea temporarily
Show Answer
Answer: C – The diaphragm flattens and ribs move up and out, expanding the chest so air rushes in.
Respiration
Q31. Which word equation describes anaerobic respiration in yeast?
- (A) Glucose → ethanol + carbon dioxide + energy
- (B) Glucose + oxygen → carbon dioxide + water + energy
- (C) Glucose → lactic acid + energy
- (D) Carbon dioxide + water → glucose + oxygen
Show Answer
Answer: A – Yeast without oxygen breaks glucose down to ethanol and carbon dioxide, releasing a small amount of energy.
Q32. A germinating seed is kept in a sealed flask with soda lime to absorb carbon dioxide. A thermometer shows a temperature rise. What does this demonstrate?
- (A) Photosynthesis in the seeds
- (B) Transpiration from the seeds
- (C) Respiration in the seeds releases energy as heat
- (D) Fermentation producing ethanol
Show Answer
Answer: C – Respiring seeds release energy, some of which appears as heat, warming the flask.
Q33. Which statement compares aerobic and anaerobic respiration in mammals correctly?
- (A) Aerobic respiration produces lactic acid
- (B) Anaerobic respiration produces more energy
- (C) Aerobic respiration takes place without mitochondria
- (D) Aerobic respiration uses oxygen and releases more energy per glucose molecule
Show Answer
Answer: D – Complete breakdown with oxygen releases far more energy than partial breakdown to lactic acid.
Excretion in humans
Q34. Which waste product is excreted in sweat as well as in urine?
- (A) Carbon dioxide
- (B) Urea and salts
- (C) Glucose
- (D) Bile pigments
Show Answer
Answer: B – Sweat contains water, salts and small amounts of urea, while the kidneys excrete most urea and excess salts.
Q35. In a kidney nephron, where does selective reabsorption mainly take place?
- (A) In the glomerulus
- (B) In the tubule, especially the first convoluted part
- (C) In the bladder
- (D) In the ureter
Show Answer
Answer: B – Useful substances such as glucose, amino acids and salts are reabsorbed from the tubule back into the blood.
Q36. A urine sample from a healthy person is tested. Which substance should not be present?
- (A) Glucose
- (B) Urea, a waste product found in urine
- (C) Water
- (D) Salts
Show Answer
Answer: A – All filtered glucose is reabsorbed, so glucose in urine suggests diabetes or kidney damage.
Coordination and response
Q37. Which neurone carries impulses from the central nervous system to an effector?
- (A) Sensory neurone
- (B) Relay neurone
- (C) Motor neurone
- (D) Receptor cell
Show Answer
Answer: C – Motor neurones carry impulses outwards from the brain or spinal cord to muscles or glands.
Q38. A person steps on a sharp object and pulls their foot away at once. Which feature makes this response fast?
- (A) The impulse travels to the brain for a decision first
- (B) The response is learned over time
- (C) Hormones carry the signal
- (D) The reflex arc is short and does not involve conscious thought
Show Answer
Answer: D – Reflex arcs bypass conscious processing, so the effector responds almost immediately.
Q39. Which plant response is shown when roots grow towards water?
- (A) Phototropism
- (B) Geotropism
- (C) Thigmotropism
- (D) Hydrotropism
Show Answer
Answer: D – Hydrotropism is growth in response to water, while phototropism responds to light and geotropism to gravity.
Drugs
Q40. Which drug is a stimulant that increases alertness and heart rate?
- (A) Alcohol, a depressant drug in drinks
- (B) Caffeine
- (C) Heroin
- (D) Insulin
Show Answer
Answer: B – Caffeine stimulates the nervous system, while alcohol and heroin are depressants.
Q41. Why does long-term smoking increase the risk of emphysema?
- (A) Smoke damages alveoli walls, reducing surface area for gas exchange
- (B) Smoke increases the number of alveoli
- (C) Smoke thickens the diaphragm
- (D) Smoke adds oxygen to the blood
Show Answer
Answer: A – Damaged alveoli break down into larger air spaces with less surface area, making breathing less efficient.
Q42. Which statement about alcohol and driving is correct?
- (A) Alcohol improves reaction time
- (B) Alcohol has no effect on judgement
- (C) Alcohol slows reactions and impairs judgement, increasing accident risk
- (D) Alcohol only affects the liver, not the brain
Show Answer
Answer: C – As a depressant, alcohol slows the nervous system, so drivers react more slowly and judge distances poorly.
Reproduction
Q43. Which structure protects a developing human embryo and contains amniotic fluid?
- (A) The amnion
- (B) The ovary
- (C) The cervix
- (D) The oviduct
Show Answer
Answer: A – The amnion is a membrane sac filled with fluid that cushions and protects the embryo.
Q44. In flowering plants, which process transfers pollen from an anther to a stigma?
- (A) Fertilisation
- (B) Germination
- (C) Pollination
- (D) Dispersal
Show Answer
Answer: C – Pollination is the transfer of pollen, while fertilisation is the later fusion of gametes.
Q45. Which advantage does seed dispersal give to a plant species?
- (A) It produces genetically identical offspring
- (B) It prevents all competition
- (C) It stops pollination occurring
- (D) It reduces competition between parent and offspring and colonises new areas
Show Answer
Answer: D – Spreading seeds widely means seedlings do not all compete in one spot and new habitats can be occupied.
Inheritance
Q46. A gene has two alleles, B for brown eyes and b for blue eyes, with B dominant. What is the phenotype of a Bb individual?
- (A) Blue eyes
- (B) Brown eyes
- (C) Green eyes
- (D) No eye colour
Show Answer
Answer: B – The dominant allele is expressed in the phenotype even when present in a single copy.
Q47. Which diagram is used to predict the genotypes of offspring from a cross?
- (A) A food web
- (B) A Punnett square
- (C) A pyramid of energy
- (D) A pedigree chart only
Show Answer
Answer: B – A Punnett square lays out possible gamete combinations and the resulting offspring genotypes.
Q48. Cystic fibrosis is caused by a recessive allele. Two carrier parents have a child. What is the chance the child has cystic fibrosis?
- (A) 1 in 4
- (B) 1 in 2
- (C) 3 in 4
- (D) 4 in 4
Show Answer
Answer: A – A cross between two carriers (Ff x Ff) gives one FF, two Ff and one ff, so one quarter are affected.
Variation and selection
Q49. Which statement about variation in a population is correct?
- (A) All variation is caused by the environment
- (B) All variation is inherited
- (C) Variation arises from genes, environment, or both
- (D) Variation prevents natural selection
Show Answer
Answer: C – Some traits vary mainly through genes, some through environment, and many through a combination of both.
Q50. A population of moths changes colour over generations after pollution darkens tree bark. Which process explains this?
- (A) Artificial selection
- (B) Genetic engineering
- (C) Asexual reproduction
- (D) Natural selection
Show Answer
Answer: D – Darker moths were better camouflaged on dark bark, survived predation more often, and passed on their colour genes.
Q51. Which of these traits shows discontinuous variation?
- (A) Height in humans
- (B) Leaf length in a plant, varying continuously
- (C) Mass of a seed
- (D) Ability to roll the tongue
Show Answer
Answer: D – Tongue rolling is either possible or not, with no intermediate form, unlike height or mass.
Organisms and their environment
Q52. Which term describes all the living and non-living parts of an area interacting together?
- (A) Population
- (B) Ecosystem
- (C) Community
- (D) Habitat
Show Answer
Answer: B – An ecosystem includes the community of organisms plus the abiotic factors they interact with.
Q53. In the carbon cycle, which process removes carbon dioxide from the atmosphere?
- (A) Photosynthesis
- (B) Respiration, which releases carbon dioxide
- (C) Combustion
- (D) Decomposition
Show Answer
Answer: A – Photosynthesis takes in carbon dioxide and fixes its carbon into organic molecules in plants.
Q54. Which organisms in a food chain are secondary consumers?
- (A) Producers, green plants at the base of a food chain
- (B) Herbivores
- (C) Carnivores that eat herbivores
- (D) Decomposers
Show Answer
Answer: C – Primary consumers eat producers, and secondary consumers eat primary consumers.
Human influences on ecosystems
Q55. Which human activity is a major cause of habitat loss for rainforest species?
- (A) Clearing forest for agriculture and timber
- (B) Creating national parks
- (C) Breeding programmes in zoos, away from the wild
- (D) Recycling waste paper
Show Answer
Answer: A – Large-scale clearance destroys forest habitat and fragments what remains, threatening many species.
Q56. Which gas is released from fertilisers and contributes to the greenhouse effect?
- (A) Oxygen
- (B) Nitrogen gas, which makes up most of the air
- (C) Nitrous oxide
- (D) Hydrogen
Show Answer
Answer: C – Nitrous oxide from nitrogen fertilisers and animal waste is a potent greenhouse gas.
Q57. Sustainable development means which of the following?
- (A) Using resources as fast as possible
- (B) Meeting only present needs with no regard for the future
- (C) Banning all use of natural resources
- (D) Meeting present needs without reducing the ability of future generations to meet theirs
Show Answer
Answer: D – Sustainable use balances human needs with conservation, so resources remain available long term.
Biotechnology and genetic modification
Q58. Which enzyme is used to cut DNA at specific sites during genetic modification?
- (A) Amylase, an enzyme that digests starch
- (B) Restriction enzyme
- (C) Lipase
- (D) Catalase
Show Answer
Answer: B – Restriction enzymes cut DNA at recognised sequences, allowing a desired gene to be removed or inserted.
Q59. Why are bacteria useful for producing human proteins such as insulin?
- (A) They have no DNA of their own
- (B) They reproduce rapidly and can express the inserted human gene
- (C) They need no nutrients to grow
- (D) They produce antibodies against insulin
Show Answer
Answer: B – Fast bacterial growth in fermenters gives large amounts of protein quickly from a single modified strain.
Q60. Which statement describes a genetically modified organism?
- (A) An organism whose genetic material has been changed by adding, removing or altering a gene
- (B) An organism grown only by selective breeding
- (C) An organism with no genetic material
- (D) An organism that reproduces only asexually
Show Answer
Answer: A – Genetic modification directly changes DNA, unlike selective breeding, which chooses among naturally occurring variants.
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