IGCSE Biology Practice Test 13 – 60 Questions with Answers (Cambridge 0610)
This test revisits all twenty-one syllabus topics, so treat any wrong answer as a prompt to reread that section before the next test.
Characteristics and classification of living organisms
Q1. Which organism belongs to the kingdom Prokaryote?
- (A) A mushroom
- (B) A green alga
- (C) A fern
- (D) A bacterium
Show Answer
Answer: D – Prokaryotes are single-celled organisms without a true nucleus, and bacteria are the main example.
Q2. Which characteristic do all living organisms show?
- (A) They all move from place to place
- (B) They all carry out respiration
- (C) They all photosynthesise
- (D) They all have a backbone
Show Answer
Answer: B – Respiration releases energy for life processes and occurs in every living cell, plant or animal.
Q3. What is the correct order of the classification ranks from largest to smallest?
- (A) Kingdom, phylum, class, order, family, genus, species
- (B) Species, genus, family, order, class, phylum, kingdom
- (C) Kingdom, class, phylum, genus, family, order, species
- (D) Phylum, kingdom, order, class, species, genus, family
Show Answer
Answer: A – Classification runs from the broad kingdom down through phylum, class, order, family and genus to the species.
Organisation of the organism
Q4. Which pair correctly matches an organelle with its function?
- (A) Ribosome: aerobic respiration
- (B) Vacuole: protein synthesis
- (C) Cell membrane: controls substances entering and leaving the cell
- (D) Nucleus: photosynthesis
Show Answer
Answer: C – The cell membrane is partially permeable and regulates what passes in and out of the cell.
Q5. Which tissue in a flowering plant is made of dead, hollow cells joined end to end?
- (A) Xylem tissue
- (B) Phloem tissue
- (C) Epidermal tissue
- (D) Mesophyll tissue
Show Answer
Answer: A – Xylem vessels are formed from dead cells with no cross walls, creating continuous tubes for water transport.
Q6. A ciliated epithelial cell in the airways has tiny hair-like projections. What is their function?
- (A) To absorb nutrients from food
- (B) To contract and move bones
- (C) To sweep mucus and trapped particles upwards
- (D) To produce antibodies against pathogens
Show Answer
Answer: C – Beating cilia move the mucus layer, with dust and microbes trapped in it, away from the lungs.
Movement into and out of cells
Q7. Which factor increases the rate of diffusion of oxygen into a cell?
- (A) A thicker cell membrane, giving a longer diffusion distance
- (B) A smaller surface area
- (C) A lower temperature
- (D) A steeper concentration gradient
Show Answer
Answer: D – A larger difference in concentration across the membrane speeds up net diffusion.
Q8. An animal cell is placed in a solution with the same solute concentration as its cytoplasm. What happens?
- (A) The cell bursts
- (B) There is no net movement of water, so the cell stays the same size
- (C) The cell shrinks rapidly
- (D) The cell swells until it bursts
Show Answer
Answer: B – With equal concentrations on both sides, water moves both ways equally, so there is no net osmosis.
Q9. Which process moves glucose from the ileum into the blood when glucose is already more concentrated in the blood?
- (A) Osmosis
- (B) Active transport
- (C) Simple diffusion
- (D) Transpiration
Show Answer
Answer: B – Moving glucose against its gradient needs energy, which is the definition of active transport.
Biological molecules
Q10. Which elements are present in a protein but not in a carbohydrate?
- (A) Nitrogen
- (B) Carbon
- (C) Hydrogen
- (D) Oxygen
Show Answer
Answer: A – Proteins contain nitrogen in their amino acids, while carbohydrates contain only carbon, hydrogen and oxygen.
Q11. Which food test uses ethanol to show the presence of fat?
- (A) Benedict’s test
- (B) Iodine test
- (C) Emulsion test
- (D) Biuret test
Show Answer
Answer: C – In the emulsion test, fat dissolved in ethanol forms a cloudy white emulsion when water is added.
Q12. Amino acids are the building blocks of which type of molecule?
- (A) Fat
- (B) Starch, a carbohydrate storage molecule
- (C) DNA
- (D) Protein
Show Answer
Answer: D – Proteins are long chains of amino acids joined by peptide bonds.
Enzymes
Q13. A student investigates catalase breaking down hydrogen peroxide. The reaction is fastest at 37 degrees Celsius and much slower at 60 degrees Celsius. Why?
- (A) Hydrogen peroxide evaporates at 60 degrees
- (B) The substrate is used up faster at low temperature
- (C) Catalase works only in the liver
- (D) At 60 degrees the enzyme begins to denature
Show Answer
Answer: D – Above its optimum, heat disrupts the enzyme shape, so fewer substrate molecules fit the active site.
Q14. Which enzyme digests fats into fatty acids and glycerol?
- (A) Amylase
- (B) Lipase
- (C) Maltase
- (D) Pepsin
Show Answer
Answer: B – Lipase, made in the pancreas and small intestine, breaks down fats in the presence of bile.
Q15. What happens to an enzyme after it has catalysed a reaction?
- (A) It remains unchanged and can be used again
- (B) It is converted into the product
- (C) It is broken down by the substrate
- (D) It changes into a different enzyme
Show Answer
Answer: A – As a catalyst, an enzyme is not consumed in the reaction and can catalyse further reactions.
Plant nutrition
Q16. Why do plant leaves turn yellow when magnesium is lacking from the soil?
- (A) Nitrate ions are needed to make proteins
- (B) Phosphate ions are needed to make DNA
- (C) Magnesium is needed to make chlorophyll
- (D) Calcium ions are needed to form chlorophyll in the palisade cells of leaves
Show Answer
Answer: C – Magnesium is part of the chlorophyll molecule, so a shortage reduces chlorophyll and leaves turn yellow.
Q17. Why do plants need nitrate ions from the soil?
- (A) To make amino acids and proteins
- (B) To make chlorophyll directly in the leaves
- (C) To open and close stomata
- (D) To store energy as starch
Show Answer
Answer: A – Nitrates supply nitrogen for amino acids, which are joined to form plant proteins and enzymes.
Q18. A variegated leaf has green and white patches. After exposure to light, only the green patches test positive for starch. What does this prove?
- (A) White patches store starch better
- (B) Starch is made in the roots
- (C) Chlorophyll is needed for photosynthesis
- (D) Light is not needed for photosynthesis
Show Answer
Answer: C – Only the chlorophyll-containing green areas could photosynthesise and produce starch.
Human nutrition
Q19. Which digestive juice contains hydrochloric acid?
- (A) Saliva
- (B) Pancreatic juice
- (C) Bile
- (D) Gastric juice
Show Answer
Answer: D – Gastric juice in the stomach contains hydrochloric acid, which kills bacteria and gives pepsin its optimum pH.
Q20. After absorption, amino acids and glucose from the ileum are carried first to which organ?
- (A) The kidney
- (B) The liver
- (C) The heart
- (D) The lung
Show Answer
Answer: B – Blood from the ileum travels in the hepatic portal vein to the liver, where nutrients are processed.
Q21. Which deficiency disease is caused by a lack of vitamin C?
- (A) Rickets
- (B) Scurvy
- (C) Anaemia
- (D) Kwashiorkor
Show Answer
Answer: B – Vitamin C is needed to make collagen, so deficiency causes bleeding gums and slow wound healing, known as scurvy.
Transport in plants
Q22. Water enters a plant through root hair cells mainly by which process?
- (A) Osmosis
- (B) Active transport
- (C) Translocation
- (D) Photosynthesis
Show Answer
Answer: A – Root hair cells have a higher solute concentration than soil water, so water enters by osmosis.
Q23. Which environmental change would reduce transpiration most?
- (A) Increasing temperature
- (B) Increasing wind speed
- (C) Increasing humidity
- (D) Increasing light intensity
Show Answer
Answer: C – High humidity lowers the water vapour gradient between leaf and air, slowing evaporation from the leaf.
Q24. In a cross-section of a stem, where is the phloem found relative to the xylem?
- (A) Inside the xylem ring
- (B) Scattered through the pith in the centre of the stem
- (C) Only in the roots
- (D) Outside the xylem, nearer the surface
Show Answer
Answer: D – In vascular bundles, phloem lies outside the xylem, closer to the stem surface.
Transport in animals
Q25. Which vessel carries blood at the highest pressure in the body?
- (A) Vena cava
- (B) Pulmonary vein
- (C) Capillary
- (D) Aorta
Show Answer
Answer: D – The aorta receives blood directly from the powerful left ventricle, so pressure there is highest.
Q26. Why do arteries have thick, elastic walls?
- (A) To allow exchange of gases
- (B) To withstand high pressure and smooth out the pulse
- (C) To prevent backflow with valves, as in veins, under low pressure
- (D) To carry blood at low pressure
Show Answer
Answer: B – Elastic artery walls stretch with each heartbeat and recoil, maintaining pressure between beats.
Q27. What is the function of platelets in blood?
- (A) To help blood clot at a wound
- (B) To carry oxygen
- (C) To fight pathogens
- (D) To carry dissolved food
Show Answer
Answer: A – Platelets trigger clotting, sealing a wound and preventing further blood loss and entry of pathogens.
Diseases and immunity
Q28. Which disease is caused by a virus and spread by droplets in the air?
- (A) Cholera
- (B) Tuberculosis
- (C) Influenza
- (D) Malaria
Show Answer
Answer: C – Influenza is a viral disease spread when an infected person coughs or sneezes droplets into the air.
Q29. Which statement describes passive immunity?
- (A) Antibodies are received ready-made, for example across the placenta
- (B) The body makes memory cells after infection
- (C) Vaccination triggers a long-term response
- (D) White blood cells engulf the pathogen
Show Answer
Answer: A – Passive immunity gives immediate but short-term protection, because no memory cells are made.
Q30. HIV weakens the immune system by attacking which cells?
- (A) Red blood cells
- (B) Platelets
- (C) Lymphocytes
- (D) Nerve cells
Show Answer
Answer: C – HIV infects and destroys lymphocytes, reducing the body’s ability to fight other infections.
Gas exchange in humans
Q31. What is the main function of the mucus and cilia lining the airways?
- (A) To absorb oxygen quickly
- (B) To warm the air only
- (C) To produce antibodies
- (D) To trap dust and microbes and move them away from the lungs
Show Answer
Answer: D – Sticky mucus traps particles, and beating cilia sweep the mucus upwards to be swallowed or coughed out.
Q32. During exhalation, the intercostal muscles relax and the diaphragm relaxes. What happens to air pressure in the lungs?
- (A) It falls below atmospheric pressure
- (B) It rises above atmospheric pressure, so air flows out
- (C) It stays equal to atmospheric pressure
- (D) It falls to zero
Show Answer
Answer: B – As chest volume decreases, air is compressed, pressure rises, and air is forced out of the lungs.
Q33. Which adaptation of alveoli gives them a very large total surface area?
- (A) A thick muscular wall around each air sac
- (B) Millions of tiny air sacs
- (C) Rings of cartilage
- (D) A coating of mucus
Show Answer
Answer: B – The lungs contain millions of alveoli, whose combined surface area is large enough for rapid gas exchange.
Respiration
Q34. Which of these uses of energy released in respiration occurs in plants?
- (A) Active uptake of mineral ions by roots
- (B) Contraction of heart muscle
- (C) Movement of a sperm cell
- (D) Maintenance of body temperature in birds
Show Answer
Answer: A – Plants use respiratory energy for active transport of ions into root cells, for growth, and for making proteins.
Q35. A muscle cell respires anaerobically for a short time, then oxygen becomes available again. What happens to the lactic acid?
- (A) It is stored permanently in the muscle
- (B) It is converted to glucose in the lungs
- (C) It is oxidised in the liver, using oxygen
- (D) It is excreted in sweat
Show Answer
Answer: C – During recovery, extra oxygen is used in the liver to break down lactic acid, which is why an oxygen debt is repaid.
Q36. Which statement is true for both aerobic and anaerobic respiration?
- (A) Both need oxygen
- (B) Both release the same amount of energy per glucose molecule
- (C) Both produce carbon dioxide
- (D) Both release energy from glucose
Show Answer
Answer: D – Both pathways break down glucose to release energy, but aerobic respiration releases far more energy and needs oxygen.
Excretion in humans
Q37. Urea is formed in which organ, and from what?
- (A) Kidney, from excess water filtered from blood
- (B) Bladder, from urine
- (C) Pancreas, from glucose
- (D) Liver, from excess amino acids
Show Answer
Answer: D – In the liver, excess amino acids are deaminated, producing urea, which the kidneys then excrete.
Q38. Which vessel carries blood away from the kidney after filtration?
- (A) Renal artery
- (B) Renal vein
- (C) Ureter
- (D) Hepatic vein
Show Answer
Answer: B – Filtered blood leaves the kidney in the renal vein, while urine leaves through the ureter.
Q39. Why is the bladder able to store urine until it is released?
- (A) Its muscular wall can stretch and its sphincter stays closed
- (B) The kidneys stop making urine at night
- (C) Urine is reabsorbed into the blood from the bladder
- (D) The ureter blocks the bladder outlet
Show Answer
Answer: A – The bladder wall stretches as it fills, and a ring of muscle at its outlet keeps urine in until urination.
Coordination and response
Q40. In the eye, which structure changes shape to focus light on the retina?
- (A) The pupil
- (B) The cornea only
- (C) The lens
- (D) The iris
Show Answer
Answer: C – Ciliary muscles adjust the lens shape: a fatter lens focuses near objects, a thinner lens focuses distant objects.
Q41. A person with diabetes mellitus does not produce enough insulin. What happens to their blood glucose after a meal?
- (A) It rises higher than normal and stays high longer
- (B) It falls to zero
- (C) It remains exactly constant
- (D) It is converted to fat at once
Show Answer
Answer: A – Without enough insulin, glucose is not taken up by cells or stored as glycogen, so blood glucose remains high.
Q42. Which hormone is released by the adrenal glands in a frightening situation?
- (A) Insulin
- (B) Thyroxine, a hormone controlling metabolic rate
- (C) Adrenaline
- (D) Glucagon
Show Answer
Answer: C – Adrenaline from the adrenal glands prepares the body for fight or flight.
Drugs
Q43. Carbon monoxide in cigarette smoke harms the body because it does which of the following?
- (A) Causes immediate addiction
- (B) Coats the airways with tar
- (C) Paralyses the cilia permanently
- (D) Binds to haemoglobin, reducing oxygen transport
Show Answer
Answer: D – Carbon monoxide binds haemoglobin more strongly than oxygen, so less oxygen reaches respiring tissues.
Q44. Drinking alcohol during pregnancy is risky mainly because alcohol can do what?
- (A) Prevent the mother digesting food
- (B) Cross the placenta and damage the developing baby
- (C) Stop the baby breathing after birth only
- (D) Cause the mother to produce less milk permanently
Show Answer
Answer: B – Alcohol passes through the placenta into the baby’s blood and can harm its development, especially the brain.
Q45. Why is it important to finish a full course of prescribed antibiotics?
- (A) To make the tablets taste better
- (B) To kill all the bacteria and reduce the chance of resistant strains surviving
- (C) To prevent the immune system working
- (D) To ensure the virus is also killed
Show Answer
Answer: B – Stopping early can leave the most resistant bacteria alive, allowing them to multiply and spread resistance.
Reproduction
Q46. Which process in sexual reproduction restores the diploid chromosome number?
- (A) Fertilisation
- (B) Meiosis
- (C) Mitosis
- (D) Pollination, the transfer of pollen to a stigma
Show Answer
Answer: A – Two haploid gametes fuse at fertilisation to form a diploid zygote.
Q47. Which statement about asexual reproduction is correct?
- (A) It needs two parents
- (B) It involves meiosis and fertilisation
- (C) It produces genetically varied offspring
- (D) It produces offspring genetically identical to the parent
Show Answer
Answer: D – Asexual reproduction uses mitosis only, so offspring are clones of the single parent, barring mutation.
Inheritance
Q48. A pea plant with genotype AA is crossed with one of genotype aa. What are the genotypes of all the offspring?
- (A) AA only
- (B) aa only
- (C) AA and aa in equal numbers
- (D) Aa only
Show Answer
Answer: D – Each offspring receives A from one parent and a from the other, so all are heterozygous Aa.
Q49. Which statement about sex determination in humans is correct?
- (A) The egg determines the sex of the child
- (B) The sperm determines the sex, because it may carry X or Y
- (C) Both parents contribute a Y chromosome to a son
- (D) Sex is determined by the environment after birth
Show Answer
Answer: B – Eggs always carry X, while sperm carry X or Y, so fertilisation by a Y sperm produces a male child.
Variation and selection
Q50. Which source of genetic variation occurs when chromosomes exchange sections during meiosis?
- (A) Crossing over
- (B) Mitosis
- (C) Cloning
- (D) Fertilisation only
Show Answer
Answer: A – Crossing over swaps segments between homologous chromosomes, creating new allele combinations in gametes.
Q51. Selective breeding of cattle for high milk yield is an example of which process?
- (A) Natural selection
- (B) Mutation
- (C) Artificial selection
- (D) Genetic modification
Show Answer
Answer: C – Humans choose parents with desired traits and breed from them over generations, which is artificial selection.
Organisms and their environment
Q52. Which statement describes a community?
- (A) All the populations of different species living together in a habitat
- (B) A single species living in one area
- (C) Only the producers in an ecosystem
- (D) The non-living factors of a habitat
Show Answer
Answer: A – A community is made up of all the interacting populations of different species in a habitat.
Q53. A food chain is: grass → rabbit → fox. What is the trophic level of the rabbit?
- (A) Producer
- (B) Decomposer
- (C) Primary consumer
- (D) Secondary consumer
Show Answer
Answer: C – The rabbit eats the producer, so it is the first consumer level, a herbivore.
Q54. Why do food chains rarely have more than five trophic levels?
- (A) Producers run out of sunlight
- (B) Consumers stop eating after five levels
- (C) Decomposers break the chain
- (D) Too little energy remains after successive losses
Show Answer
Answer: D – With roughly 90 percent of energy lost at each transfer, very little is left to support a sixth level.
Human influences on ecosystems
Q55. Which human activity increases the amount of methane in the atmosphere?
- (A) Planting new forests, which absorb carbon dioxide
- (B) Keeping large numbers of cattle
- (C) Recycling paper
- (D) Using solar panels
Show Answer
Answer: B – Cattle digestion releases methane, a powerful greenhouse gas, and rice paddies and waste also contribute.
Q56. What is the main cause of acid rain?
- (A) Carbon dioxide from respiration
- (B) Sulfur dioxide and nitrogen oxides from burning fossil fuels
- (C) Oxygen released by plants
- (D) Water vapour from oceans
Show Answer
Answer: B – These gases dissolve in rainwater to form acids, which damage trees, lakes and buildings.
Q57. A species becomes extinct when its habitat is destroyed. Which conservation measure directly protects its remaining habitat?
- (A) Creating a protected nature reserve
- (B) Keeping the species in a zoo only
- (C) Breeding it in captivity only
- (D) Storing its seeds in a bank only, away from the habitat
Show Answer
Answer: A – A reserve protects the habitat itself, allowing the species to live and breed in its natural environment.
Biotechnology and genetic modification
Q58. Which product is made using yeast in a fermenter?
- (A) Cheese only, made with bacterial cultures
- (B) Yoghurt only
- (C) Bread and alcoholic drinks
- (D) Insulin only
Show Answer
Answer: C – Yeast fermentation produces carbon dioxide for raising bread and ethanol for alcoholic drinks.
Q59. A plant is modified with a gene for resistance to insect pests. What is a possible environmental benefit?
- (A) The plant needs no light
- (B) The plant grows without soil in water alone
- (C) The plant produces no pollen
- (D) Less insecticide spraying is needed
Show Answer
Answer: D – If the crop can resist pests itself, farmers can reduce chemical insecticide use, which also protects other insects.
Q60. Which stage comes first when genetically modifying a bacterium to produce a human protein?
- (A) The modified bacteria are grown in a fermenter
- (B) The protein is purified from the culture
- (C) The human gene is isolated and inserted into a plasmid
- (D) The bacteria are grown in soil and left to produce the protein naturally over many weeks
Show Answer
Answer: C – The gene for the protein is first placed into a plasmid vector, which is then introduced into the bacterium.
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