IGCSE Biology Practice Test 16 – 60 Questions with Answers (Cambridge 0610)
This test covers the full IGCSE Biology syllabus in one sitting, so use it to check which topics need more revision before your next practice round.
Characteristics and classification of living organisms
Q1. Which life process involves the release of energy from food substances inside cells?
- (A) Excretion
- (B) Respiration
- (C) Sensitivity in this context, when the other conditions are taken into account
- (D) Nutrition
Show Answer
Answer: B – Respiration releases energy from food substances, which cells then use for other life processes.
Q2. A scientist groups organisms by shared features into progressively smaller groups. Which sequence is in the correct order from largest to smallest?
- (A) Genus, family, order, class
- (B) Species, genus, family, order in this context, when the other conditions are taken into account
- (C) Class, order, family, genus
- (D) Kingdom, phylum, class, order
Show Answer
Answer: D – The hierarchy runs kingdom, phylum, class, order, family, genus, species, from largest to smallest.
Q3. Which pair of names correctly shows the binomial system for humans?
- (A) Homo sapiens
- (B) sapiens Homo
- (C) Homo Sapiens
- (D) human sapiens
Show Answer
Answer: A – The genus name comes first with a capital letter, followed by the species name in lower case.
Organisation of the organism
Q4. Which level of organisation comes between a tissue and an organ system?
- (A) Cell
- (B) Organelle
- (C) Organ
- (D) Organism
Show Answer
Answer: C – Tissues working together form an organ, and organs working together form an organ system.
Q5. Which cell structure controls what enters and leaves the cell?
- (A) Nucleus
- (B) Cytoplasm
- (C) Cell membrane
- (D) Mitochondrion in this context, when the other conditions are taken into account
Show Answer
Answer: C – The cell membrane is partially permeable and regulates the movement of substances into and out of the cell.
Q6. Which organelle is the site of protein synthesis in a cell?
- (A) Ribosome
- (B) Vacuole
- (C) Chloroplast
- (D) Cell wall
Show Answer
Answer: A – Ribosomes assemble amino acids into proteins, and they occur in both plant and animal cells.
Movement into and out of cells
Q7. Which process describes the net movement of particles from a region of higher concentration to a region of lower concentration?
- (A) Active transport
- (B) Osmosis
- (C) Phagocytosis
- (D) Diffusion
Show Answer
Answer: D – Diffusion is the net movement of particles down a concentration gradient until equilibrium is reached.
Q8. A plant cell is placed in pure water. What happens to the cell?
- (A) It shrinks as water leaves in this context, when the other conditions are taken into account
- (B) It becomes turgid as water enters
- (C) It bursts as water enters
- (D) It stays unchanged
Show Answer
Answer: B – Water enters by osmosis and the cell becomes turgid, but the cell wall prevents it from bursting.
Q9. Which feature increases the rate of diffusion across a surface?
- (A) A thicker surface
- (B) A smaller surface area
- (C) A lower temperature
- (D) A larger surface area
Show Answer
Answer: D – A larger surface area provides more space for particles to cross, so diffusion happens faster.
Biological molecules
Q10. Which test gives a brick-red precipitate with a reducing sugar when heated?
- (A) Iodine test
- (B) Benedict’s test
- (C) Biuret test
- (D) Emulsion test in this context, when the other conditions are taken into account
Show Answer
Answer: B – Benedict’s solution turns from blue to a brick-red precipitate when heated with a reducing sugar.
Q11. Which molecule is formed when many glucose units join together in a plant storage carbohydrate?
- (A) Cellulose
- (B) Glycogen
- (C) Starch
- (D) Sucrose
Show Answer
Answer: C – Starch is the storage carbohydrate in plants and is made from many glucose units joined together.
Enzymes
Q12. What happens to most enzymes when they are heated well above their optimum temperature?
- (A) They are denatured
- (B) They work faster permanently
- (C) They become substrates
- (D) They stop being proteins
Show Answer
Answer: A – High temperature changes the shape of the active site, so the enzyme is denatured and can no longer function.
Q13. Which statement best describes how an enzyme speeds up a reaction?
- (A) It lowers the activation energy
- (B) It raises the activation energy in this context, when the other conditions are taken into account
- (C) It is used up in the reaction
- (D) It changes the products formed
Show Answer
Answer: A – Enzymes lower the activation energy needed, so the reaction proceeds faster without the enzyme being used up.
Plant nutrition
Q14. Which set of conditions gives the fastest rate of photosynthesis in a leaf?
- (A) Low light and low carbon dioxide in this context, when the other conditions are taken into account
- (B) High light and high temperature
- (C) Bright light, adequate carbon dioxide and a suitable temperature
- (D) Darkness and high carbon dioxide
Show Answer
Answer: C – Photosynthesis needs light and carbon dioxide, and enzymes work best at a suitable temperature.
Q15. A leaf is tested for starch after being kept in darkness for two days and then in light for a few hours. Which result is expected?
- (A) No starch in any part
- (B) Starch present throughout the leaf
- (C) Starch only in the veins in this context, when the other conditions are taken into account
- (D) Starch only in the stalk
Show Answer
Answer: B – Destarching removes stored starch, and photosynthesis in the light then produces new starch throughout the leaf.
Human nutrition
Q16. Which organ produces bile in the human digestive system?
- (A) Pancreas
- (B) Stomach
- (C) Gall bladder
- (D) Liver
Show Answer
Answer: D – The liver produces bile, which is stored in the gall bladder before release into the small intestine.
Q17. Which enzyme digests starch to maltose in the mouth and small intestine?
- (A) Lipase
- (B) Protease
- (C) Amylase
- (D) Pepsin
Show Answer
Answer: C – Amylase breaks down starch into maltose, starting in the mouth and continuing in the small intestine.
Q18. Which organ stores bile before it is released into the small intestine?
- (A) Liver
- (B) Gall bladder
- (C) Pancreas
- (D) Spleen
Show Answer
Answer: B – Bile made in the liver is stored in the gall bladder and released into the duodenum after a meal.
Transport in plants
Q19. What is the function of the cambium in a plant stem?
- (A) It produces new xylem and phloem cells as the stem grows thicker
- (B) It transports dissolved sugars from the leaves to the growing root tips of the plant
- (C) It protects the stem surface
- (D) It absorbs water from the soil
Show Answer
Answer: A – The cambium is a meristem that divides to form new xylem on the inside and new phloem on the outside.
Q20. Which process causes most water loss from a leaf?
- (A) Photosynthesis
- (B) Respiration
- (C) Active uptake
- (D) Transpiration
Show Answer
Answer: D – Transpiration is the loss of water vapour from leaves, mainly through open stomata.
Q21. Which factor increases the rate of transpiration?
- (A) High humidity
- (B) Low temperature
- (C) Still air
- (D) Moving air
Show Answer
Answer: D – Moving air removes water vapour from around the leaf, maintaining a steep diffusion gradient for more loss.
Transport in animals
Q22. Which chamber of the heart pumps blood to the whole body?
- (A) Left ventricle
- (B) Right ventricle
- (C) Left atrium
- (D) Right atrium
Show Answer
Answer: A – The left ventricle has the thickest wall because it must pump blood around the entire body.
Q23. Which chamber of the heart receives blood from the pulmonary vein?
- (A) Right atrium
- (B) Left atrium
- (C) Right ventricle
- (D) Left ventricle, which pumps blood around the whole body through the aorta
Show Answer
Answer: B – Oxygenated blood from the lungs enters the left atrium through the pulmonary vein.
Q24. Which component of blood carries oxygen around the body?
- (A) Platelets
- (B) Plasma
- (C) Red blood cells
- (D) White blood cells
Show Answer
Answer: C – Red blood cells contain haemoglobin, which binds oxygen and releases it in respiring tissues.
Diseases and immunity
Q25. Which type of pathogen causes cholera?
- (A) Virus
- (B) Bacterium
- (C) Fungus
- (D) Protoctist
Show Answer
Answer: B – Cholera is caused by a bacterium that spreads through water contaminated with sewage.
Q26. How does active immunity develop after vaccination?
- (A) The body makes its own antibodies
- (B) Ready-made antibodies are injected
- (C) Antibiotics kill the pathogen
- (D) White cells stop dividing
Show Answer
Answer: A – A vaccine stimulates lymphocytes to produce antibodies and memory cells against that pathogen.
Q27. Which defence prevents most pathogens from entering the body through the nose?
- (A) Stomach acid
- (B) Skin oils
- (C) Mucus and cilia
- (D) Blood clotting
Show Answer
Answer: C – Mucus traps pathogens in the nose and airways, and cilia sweep the mucus away from the lungs.
Gas exchange in humans
Q28. Which feature of the alveoli adapts them for efficient gas exchange?
- (A) A thick wall
- (B) A dry surface
- (C) A single air sac
- (D) A large surface area and rich blood supply
Show Answer
Answer: D – Millions of alveoli give a huge surface area, with thin walls and many capillaries for rapid diffusion.
Q29. During inhalation, what happens to the diaphragm and the ribcage?
- (A) Diaphragm relaxes and ribcage moves down
- (B) Diaphragm flattens and ribcage moves in
- (C) Diaphragm contracts and ribcage moves up and out
- (D) Diaphragm contracts and ribcage moves down
Show Answer
Answer: C – The diaphragm contracts and flattens while the external intercostal muscles raise the ribcage, increasing chest volume.
Q30. Which gas diffuses from the blood into the alveoli to be breathed out?
- (A) Oxygen
- (B) Nitrogen
- (C) Water vapour only
- (D) Carbon dioxide
Show Answer
Answer: D – Carbon dioxide is at a higher concentration in the blood than in the alveoli, so it diffuses out for exhalation.
Respiration
Q31. In which form is energy released by respiration stored for immediate use in a cell?
- (A) Glucose stored as glycogen in the cytoplasm of liver and muscle cells
- (B) ATP
- (C) Starch
- (D) Protein
Show Answer
Answer: B – Respiration builds ATP, which is broken down again whenever the cell needs energy for work.
Q32. Which product of anaerobic respiration in muscle causes fatigue?
- (A) Lactic acid
- (B) Ethanol
- (C) Carbon dioxide
- (D) Oxygen debt
Show Answer
Answer: A – Anaerobic respiration in muscle produces lactic acid, which is linked to tiredness and cramp during hard exercise.
Q33. During vigorous exercise, why does breathing rate increase?
- (A) To supply more oxygen and remove more carbon dioxide
- (B) To reduce blood flow to muscles
- (C) To store glucose in the liver
- (D) To lower the heart rate
Show Answer
Answer: A – Muscles respire faster during exercise, so they need more oxygen and produce more carbon dioxide to remove.
Excretion in humans
Q34. Which part of the kidney tubule reabsorbs most of the filtered glucose?
- (A) Glomerulus
- (B) Loop of Henle, where water is reabsorbed into the surrounding blood capillaries
- (C) Collecting duct
- (D) Proximal convoluted tubule
Show Answer
Answer: D – Glucose filtered at the glomerulus is reabsorbed into the blood in the first, proximal part of the tubule.
Q35. Where in the kidney does selective reabsorption of glucose take place?
- (A) Glomerulus
- (B) Ureter
- (C) Kidney tubule
- (D) Renal artery
Show Answer
Answer: C – Useful substances such as glucose are selectively reabsorbed from the filtrate as it passes along the kidney tubule.
Q36. Which substance is formed in the liver when excess amino acids are broken down?
- (A) Glucose
- (B) Urea
- (C) Insulin
- (D) Glycogen
Show Answer
Answer: B – Deamination in the liver removes the nitrogen part of amino acids, which is converted to urea for excretion.
Coordination and response
Q37. In a reflex action, what is the role of the relay neurone?
- (A) It carries impulses from the receptor directly to the effector without passing through the spinal cord
- (B) It connects the sensory neurone to the motor neurone in the central nervous system
- (C) It detects the stimulus
- (D) It carries out the response
Show Answer
Answer: B – Relay neurones in the brain or spinal cord link sensory neurones to motor neurones in a reflex arc.
Q38. Which sense organ contains receptors sensitive to light?
- (A) Ear
- (B) Skin
- (C) Eye
- (D) Tongue
Show Answer
Answer: C – The retina of the eye contains light-sensitive cells, the rods and cones, that detect light intensity and colour.
Q39. Which hormone lowers blood glucose concentration after a meal?
- (A) Adrenaline
- (B) Glucagon
- (C) Oestrogen
- (D) Insulin
Show Answer
Answer: D – Insulin, released by the pancreas, promotes glucose uptake and conversion to glycogen, lowering blood glucose.
Drugs
Q40. Which long-term effect can heavy drinking have on the liver?
- (A) It can cause cirrhosis, where liver tissue is replaced by scar tissue
- (B) It permanently increases the number of red blood cells and improves oxygen transport around the body
- (C) It improves coordination at any dose
- (D) It increases alertness and judgement
Show Answer
Answer: A – Long-term heavy drinking damages liver cells, and scar tissue replaces healthy tissue in cirrhosis.
Q41. Why does repeated heroin use lead to strong dependence?
- (A) It supplies vitamins the body lacks
- (B) It strengthens the immune system
- (C) It alters brain chemistry so the body craves further doses
- (D) It replaces natural hormones permanently
Show Answer
Answer: C – Heroin changes brain chemistry and produces withdrawal symptoms, so users develop a strong physical dependence.
Q42. Which statement about antibiotics is correct?
- (A) They kill bacteria but do not kill viruses
- (B) They kill viruses but do not kill bacteria in this context, when the other conditions are taken into account
- (C) They kill all pathogens equally
- (D) They prevent all future infections
Show Answer
Answer: A – Antibiotics target bacterial processes, so they are ineffective against viruses such as those causing colds.
Reproduction
Q43. Which method of reproduction produces genetically identical offspring?
- (A) Cross-pollination
- (B) Asexual reproduction
- (C) Sexual reproduction
- (D) Self-pollination only
Show Answer
Answer: B – Asexual reproduction involves a single parent and mitosis, so offspring are genetically identical clones.
Q44. In a flowering plant, where does fertilisation take place?
- (A) In the anther
- (B) On the stigma
- (C) In the petal
- (D) In the ovule
Show Answer
Answer: D – A pollen tube grows to the ovule, where the male nucleus fuses with the egg cell nucleus.
Q45. Which structure in the human female produces eggs and oestrogen?
- (A) Uterus
- (B) Cervix
- (C) Oviduct
- (D) Ovary
Show Answer
Answer: D – The ovaries release eggs at ovulation and secrete the hormone oestrogen.
Inheritance
Q46. How many chromosomes are there in a normal human body cell?
- (A) 23, the number found in a human gamete after meiosis
- (B) 92
- (C) 46
- (D) 44
Show Answer
Answer: C – Human body cells are diploid and contain 46 chromosomes, in 23 pairs.
Q47. A person has the genotype Bb for a trait where B is dominant. Which phenotype is shown?
- (A) The dominant phenotype
- (B) The recessive phenotype
- (C) A blend of both phenotypes
- (D) Neither phenotype
Show Answer
Answer: A – A single dominant allele is enough to show the dominant phenotype, so Bb shows the dominant trait.
Q48. Which process halves the chromosome number when gametes are formed?
- (A) Mitosis
- (B) Meiosis
- (C) Fertilisation
- (D) Cloning
Show Answer
Answer: B – Meiosis produces haploid gametes, so fertilisation restores the full diploid chromosome number.
Variation and selection
Q49. Which type of variation is caused only by genes and shows distinct categories?
- (A) Discontinuous variation
- (B) Continuous variation
- (C) Environmental variation in this context, when the other conditions are taken into account
- (D) Acquired variation
Show Answer
Answer: A – Discontinuous variation, such as blood group, is controlled by genes and falls into clear categories.
Q50. Which process increases variation within a population?
- (A) Asexual reproduction
- (B) Mutation
- (C) Cloning
- (D) Inbreeding
Show Answer
Answer: B – Mutations create new alleles, which increase the genetic variation available for selection to act on.
Q51. How does natural selection lead to better-adapted populations over time?
- (A) Individuals choose useful mutations
- (B) All individuals survive equally
- (C) The environment changes genes directly
- (D) Better-adapted individuals survive and pass on their alleles
Show Answer
Answer: D – Individuals with advantageous alleles are more likely to survive and reproduce, increasing those alleles in later generations.
Organisms and their environment
Q52. In a food web, what is the role of a producer?
- (A) It eats herbivores
- (B) It breaks down dead material
- (C) It makes its own food by photosynthesis
- (D) It feeds only on decomposers
Show Answer
Answer: C – Producers, usually green plants, capture light energy and make food that supports the rest of the web.
Q53. Which level of a food chain receives the least energy?
- (A) Producer
- (B) Primary consumer
- (C) Secondary consumer
- (D) Top consumer
Show Answer
Answer: D – Energy is lost at each transfer, so the top consumer receives far less energy than lower levels.
Q54. Why does energy decrease at each trophic level in a food chain?
- (A) Producers stop photosynthesis at higher levels
- (B) Consumers store all the energy they take in
- (C) Energy is lost as heat in respiration and in waste
- (D) Decomposers create new energy for consumers
Show Answer
Answer: C – At each level, much energy is lost through respiration, movement and undigested waste, so less remains for the next level.
Human influences on ecosystems
Q55. Which human activity is the main cause of increased atmospheric carbon dioxide in recent decades?
- (A) Reforestation
- (B) Burning fossil fuels
- (C) Recycling paper
- (D) Desalination
Show Answer
Answer: B – Burning coal, oil and gas releases carbon dioxide stored for millions of years into the atmosphere.
Q56. Which human activity increases carbon dioxide in the atmosphere?
- (A) Burning fossil fuels for energy and transport, releasing stored carbon
- (B) Planting large areas of forest that absorb carbon dioxide during photosynthesis each year
- (C) Loss of species from overfishing
- (D) Warming of lakes by sunlight
Show Answer
Answer: A – Burning coal, oil and gas releases carbon that was locked away for millions of years as carbon dioxide.
Q57. Which conservation measure helps protect an endangered species?
- (A) Draining its wetland habitat
- (B) Creating a protected reserve for its habitat
- (C) Introducing a new predator
- (D) Harvesting more individuals
Show Answer
Answer: B – A protected reserve preserves the habitat and reduces threats, giving the species a better chance to recover.
Biotechnology and genetic modification
Q58. Which organism is used in fermenters to produce insulin by genetic modification?
- (A) Bacteria
- (B) Viruses
- (C) Fungi that cause disease
- (D) Green algae
Show Answer
Answer: A – Bacteria given the human insulin gene can produce large quantities of insulin in fermenters.
Q59. What is a genetically modified crop?
- (A) A crop grown without fertiliser
- (B) A crop bred only by cross-pollination
- (C) A crop stored in a seed bank
- (D) A crop with a gene transferred from another organism
Show Answer
Answer: D – Genetic modification transfers a useful gene into a crop, for example to resist pests or herbicides.
Q60. Which condition is controlled in a fermenter to maximise product yield?
- (A) Complete darkness at all times
- (B) Random changes in acidity
- (C) Temperature, pH and oxygen supply
- (D) Absence of any nutrients
Show Answer
Answer: C – Fermenters control temperature, pH, oxygen and nutrient supply so microorganisms grow and produce efficiently.
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