IGCSE Biology Practice Test 11 – 60 Questions with Answers (Cambridge 0610)
This test covers every major area of the IGCSE Biology syllabus in a single sitting, so use it to find the topics that still need a closer look.
Characteristics and classification of living organisms
Q1. Which statement describes sensitivity in a living organism?
- (A) It can detect and respond to changes in its surroundings
- (B) It can make its own food using sunlight
- (C) It can move from one place to another by swimming or walking
- (D) It can break down food inside its cells
Show Answer
Answer: A – Sensitivity is the ability to detect stimuli and respond to them, for example a plant shoot bending towards light.
Q2. A student finds a small green organism with a cell wall and chloroplasts, but no true roots, stems or leaves. Which kingdom is it most likely to belong to?
- (A) Animal
- (B) Fungus
- (C) Plant
- (D) Prokaryote
Show Answer
Answer: C – Plants are multicellular, have cell walls and chloroplasts, and make food by photosynthesis.
Q3. Which feature is used to place an animal in the class Mammalia rather than in another vertebrate class?
- (A) It lays eggs in water
- (B) It breathes through moist skin
- (C) It has scales covering its body and lays eggs on land
- (D) It has hair and feeds its young on milk
Show Answer
Answer: D – Mammals are distinguished by hair or fur and mammary glands that produce milk for their young.
Organisation of the organism
Q4. Which sequence correctly shows increasing levels of organisation in a multicellular organism?
- (A) Organ system, organ, tissue, cell
- (B) Cell, tissue, organ, organ system
- (C) Tissue, cell, organ system, organ
- (D) Cell, organ, tissue, organ system
Show Answer
Answer: B – Cells of the same type form a tissue, tissues form an organ, and organs work together in an organ system.
Q5. Which structure is present in a plant cell but absent from an animal cell?
- (A) Nucleus
- (B) Chloroplast
- (C) Cell membrane
- (D) Mitochondrion
Show Answer
Answer: B – Chloroplasts are the site of photosynthesis in plant cells and are not found in animal cells.
Q6. What is the function of the ribosome in a cell?
- (A) Protein synthesis
- (B) Aerobic respiration
- (C) Storage of starch grains
- (D) Control of substances entering the cell
Show Answer
Answer: A – Ribosomes are the sites where amino acids are joined together to make proteins.
Movement into and out of cells
Q7. A red blood cell is placed in pure water. What happens to the cell and why?
- (A) It shrinks because water leaves by osmosis
- (B) It stays the same size because water cannot cross the membrane
- (C) It swells and may burst because water enters by osmosis
- (D) It swells because dissolved salts diffuse into the cell
Show Answer
Answer: C – Water moves by osmosis from the dilute surroundings into the more concentrated cell, so the cell swells.
Q8. Which process requires energy from respiration and moves substances against a concentration gradient?
- (A) Diffusion
- (B) Osmosis
- (C) Facilitated diffusion
- (D) Active transport
Show Answer
Answer: D – Active transport uses energy to move molecules or ions from a lower to a higher concentration.
Q9. How does increasing the surface area of a cell membrane affect the rate of diffusion into the cell?
- (A) It has no effect on the rate
- (B) It decreases the rate because molecules spread out
- (C) It increases the rate only for large molecules
- (D) It increases the rate because more molecules can cross at once
Show Answer
Answer: D – A larger surface area provides more membrane through which diffusing molecules can pass.
Biological molecules
Q10. Which test gives a brick-red precipitate when a sample is heated with Benedict’s solution?
- (A) Test for starch using iodine solution
- (B) Test for reducing sugar
- (C) Test for protein
- (D) Test for fat
Show Answer
Answer: B – Benedict’s solution changes from blue to a brick-red precipitate when heated with a reducing sugar such as glucose.
Q11. Which food substance is made from glycerol and fatty acids?
- (A) Fat
- (B) Starch
- (C) Glucose
- (D) Amino acid
Show Answer
Answer: A – A fat molecule is formed when three fatty acids combine with one glycerol molecule.
Q12. A sample turns blue-black when iodine solution is added. What does this result show?
- (A) Protein is present
- (B) Glucose is present
- (C) Starch is present
- (D) Vitamin C is present
Show Answer
Answer: C – Iodine solution changes from brown to blue-black in the presence of starch.
Enzymes
Q13. Why does an enzyme-catalysed reaction slow down sharply above the optimum temperature?
- (A) The enzyme is denatured and its active site changes shape
- (B) The substrate molecules stop moving altogether
- (C) The enzyme is used up in the reaction
- (D) The pH of the mixture falls to zero
Show Answer
Answer: A – High temperature breaks the bonds holding the enzyme shape, so the substrate no longer fits the active site.
Q14. Which enzyme breaks down starch into maltose in the mouth?
- (A) Lipase
- (B) Protease
- (C) Amylase
- (D) Catalase
Show Answer
Answer: C – Salivary amylase begins the digestion of starch in the mouth, producing maltose.
Q15. An experiment measures the rate of an enzyme reaction at different pH values. The graph peaks at pH 7 and falls on both sides. What is pH 7 for this enzyme?
- (A) The pH at which the enzyme is destroyed
- (B) The pH at which the substrate runs out
- (C) The pH at which no reaction occurs
- (D) The optimum pH
Show Answer
Answer: D – The optimum pH is the pH at which the enzyme works fastest.
Plant nutrition
Q16. Which two raw materials does a leaf need for photosynthesis?
- (A) Oxygen and glucose, the products of photosynthesis
- (B) Carbon dioxide and water
- (C) Nitrates and oxygen
- (D) Water and starch
Show Answer
Answer: B – Photosynthesis uses carbon dioxide from the air and water from the soil to make glucose and release oxygen.
Q17. Why are leaves of most plants thin and broad?
- (A) To reduce water loss from the surface in dry conditions
- (B) To give a large surface area for absorbing light
- (C) To keep the leaf cool in strong sunlight
- (D) To allow roots to grow more quickly
Show Answer
Answer: B – A large, thin surface lets the leaf capture more light and allows gases to diffuse in and out quickly.
Q18. A plant kept in dim light is given more light, but its rate of photosynthesis soon stops rising. Which factor is now most likely limiting the rate?
- (A) Carbon dioxide concentration
- (B) The number of leaves on the plant
- (C) The colour of the pot
- (D) The age of the soil
Show Answer
Answer: A – When light is no longer limiting, another factor such as carbon dioxide concentration or temperature limits the rate.
Human nutrition
Q19. Where is bile produced, and what is its main role in digestion?
- (A) Produced in the pancreas; it digests starch
- (B) Produced in the stomach; it kills bacteria
- (C) Produced in the liver; it emulsifies fats
- (D) Produced in the gall bladder; it absorbs glucose
Show Answer
Answer: C – Bile is made in the liver and breaks large fat droplets into smaller ones, giving lipase a larger surface area to work on.
Q20. Which adaptation of the small intestine increases the absorption of digested food?
- (A) A thick muscular wall for churning
- (B) A short length to speed up movement through the digestive system
- (C) A dry inner surface
- (D) Villi with a large surface area and a rich blood supply
Show Answer
Answer: D – Villi greatly increase surface area, and their capillaries carry absorbed nutrients away quickly.
Q21. A diet lacking vitamin D over a long period is most likely to cause which condition in children?
- (A) Scurvy
- (B) Anaemia
- (C) Night blindness
- (D) Rickets
Show Answer
Answer: D – Vitamin D is needed for calcium absorption and healthy bone formation, so deficiency weakens growing bones.
Transport in plants
Q22. Which tissue carries water from the roots to the leaves of a plant?
- (A) Phloem
- (B) Xylem
- (C) Epidermis
- (D) Mesophyll
Show Answer
Answer: B – Xylem vessels transport water and mineral ions upwards through the plant.
Q23. In a plant stem, where is phloem found relative to xylem in a vascular bundle?
- (A) On the outer side of the bundle, towards the outside of the stem
- (B) In the centre of the pith, surrounded on all sides by cortex cells and ground tissue
- (C) Below the xylem, towards the centre
- (D) Only in the roots, never in the stem
Show Answer
Answer: A – In a stem vascular bundle, phloem lies outside the xylem, with cambium between them.
Q24. On a hot, windy day, what happens to the rate of transpiration compared with a cool, still day?
- (A) It falls because stomata close permanently
- (B) It stays the same in all conditions
- (C) It rises because water vapour is removed faster
- (D) It falls because the plant absorbs less light
Show Answer
Answer: C – Heat increases evaporation and wind removes water vapour from around the leaf, steepening the diffusion gradient.
Transport in animals
Q25. Which blood vessel carries oxygenated blood from the lungs to the heart?
- (A) Pulmonary vein
- (B) Pulmonary artery
- (C) Vena cava
- (D) Aorta
Show Answer
Answer: A – The pulmonary vein is unusual because it carries oxygenated blood, from the lungs back to the left atrium.
Q26. Why does the left ventricle of the heart have a thicker wall than the right ventricle?
- (A) It pumps blood only to the lungs
- (B) It receives blood from the vena cava
- (C) It must pump blood around the whole body
- (D) It beats faster than the right ventricle
Show Answer
Answer: C – Blood from the left ventricle travels much further and against greater resistance, so a stronger contraction is needed.
Q27. Which component of blood carries oxygen to respiring tissues?
- (A) Plasma
- (B) Platelets
- (C) White blood cells
- (D) Red blood cells
Show Answer
Answer: D – Red blood cells contain haemoglobin, which binds oxygen in the lungs and releases it in the tissues.
Diseases and immunity
Q28. Which disease is caused by a virus and spread by coughing and sneezing?
- (A) Cholera, a bacterial disease spread through contaminated water supplies
- (B) Influenza
- (C) Malaria
- (D) Athlete’s foot
Show Answer
Answer: B – Influenza is a viral infection spread in droplets when an infected person coughs or sneezes.
Q29. How does vaccination give long-term protection against a disease?
- (A) It kills all bacteria in the body at once
- (B) It triggers memory cells that respond quickly if the pathogen returns
- (C) It supplies ready-made antibodies for life
- (D) It blocks the pathogen from entering the skin
Show Answer
Answer: B – After vaccination, memory cells remain, so a later infection produces a faster, larger antibody response.
Gas exchange in humans
Q30. Which feature of the alveoli helps gas exchange to happen quickly?
- (A) A very thin wall, one cell thick, with a large surface area
- (B) A thick wall lined with cartilage rings
- (C) A dry surface that prevents water loss
- (D) A muscular wall that pumps air in and out
Show Answer
Answer: A – A thin wall shortens the diffusion distance and a large total surface area allows rapid exchange of oxygen and carbon dioxide.
Q31. During inhalation, what happens to the diaphragm and the volume of the chest cavity?
- (A) The diaphragm relaxes and the volume decreases
- (B) The diaphragm relaxes and the volume increases
- (C) The diaphragm contracts and the volume increases
- (D) The diaphragm contracts and the volume decreases
Show Answer
Answer: C – The diaphragm flattens as it contracts, increasing chest volume and lowering air pressure so air flows in.
Respiration
Q32. During vigorous exercise, why does the rate of aerobic respiration in muscle cells increase?
- (A) To store more glucose as glycogen in the liver for later use during rest
- (B) To remove lactic acid from the blood
- (C) To cool the body down
- (D) To release more energy for muscle contraction
Show Answer
Answer: D – Working muscles need more energy for contraction, so respiration speeds up to supply it.
Q33. After vigorous exercise, a runner feels a sharp ache in her leg muscles. What has built up in the muscles?
- (A) Ethanol
- (B) Carbon monoxide
- (C) Glucose
- (D) Lactic acid
Show Answer
Answer: D – When oxygen supply cannot meet demand, anaerobic respiration in muscle produces lactic acid.
Excretion in humans
Q34. Which organ removes urea from the blood and forms urine?
- (A) Liver
- (B) Kidney
- (C) Bladder
- (D) Pancreas
Show Answer
Answer: B – The kidneys filter the blood, remove urea and excess salts and water, and produce urine.
Q35. Where in the kidney does ultrafiltration take place?
- (A) In the glomerulus and Bowman’s capsule
- (B) In the bladder wall
- (C) In the ureter
- (D) In the loop of Henle only, where water is reabsorbed
Show Answer
Answer: A – High pressure in the glomerulus forces small molecules through into Bowman’s capsule, while cells and large proteins stay in the blood.
Q36. A person drinks very little water on a hot day. How does the kidney respond?
- (A) It produces a large volume of dilute urine
- (B) It stops filtering the blood completely
- (C) It reabsorbs more water and produces a small volume of concentrated urine
- (D) It excretes extra urea in dilute urine
Show Answer
Answer: C – Antidiuretic hormone increases water reabsorption from the kidney tubules, conserving water when intake is low.
Coordination and response
Q37. In a reflex action, which structure carries impulses from the receptor to the central nervous system?
- (A) Sensory neurone
- (B) Motor neurone
- (C) Effector muscle
- (D) Relay neurone only
Show Answer
Answer: A – Sensory neurones carry impulses from receptors towards the brain or spinal cord.
Q38. Which hormone is released when blood glucose concentration rises after a meal?
- (A) Adrenaline
- (B) Glucagon
- (C) Insulin
- (D) Thyroxine
Show Answer
Answer: C – Insulin from the pancreas lowers blood glucose by promoting its uptake and conversion to glycogen in the liver.
Q39. A bright light is shone into a person’s eye. What happens to the pupil, and why?
- (A) It dilates to let in more light
- (B) It stays the same size
- (C) It closes completely to block light
- (D) It constricts to reduce the amount of light entering
Show Answer
Answer: D – Circular muscles in the iris contract, making the pupil smaller and protecting the retina from excess light.
Drugs
Q40. Which effect does alcohol have on the nervous system?
- (A) It speeds up reaction times
- (B) It depresses the nervous system and slows reactions
- (C) It improves coordination and judgement
- (D) It increases the rate of nerve impulses permanently
Show Answer
Answer: B – Alcohol is a depressant that slows the brain and nervous system, impairing judgement and coordination.
Q41. Smoking tobacco increases the risk of lung cancer mainly because cigarette smoke contains which substance?
- (A) Nicotine only, without any other smoke chemicals
- (B) Tar with carcinogens
- (C) Oxygen
- (D) Water vapour
Show Answer
Answer: B – Tar contains chemicals that can damage lung cells and trigger cancerous growth.
Q42. Why is heroin described as an addictive drug?
- (A) Repeated use leads to dependence and withdrawal symptoms without it
- (B) A single dose permanently damages the liver
- (C) It can only be taken by injection
- (D) It prevents all other drugs from working
Show Answer
Answer: A – Addiction means the body becomes dependent on the drug, and stopping causes unpleasant withdrawal effects.
Reproduction
Q43. In flowering plants, where are the male gametes produced?
- (A) In the ovary
- (B) In the stigma
- (C) In the anther
- (D) In the sepal
Show Answer
Answer: C – Pollen grains, which contain the male gametes, are produced in the anthers.
Q44. Which statement about fertilisation in humans is correct?
- (A) It takes place in the uterus
- (B) It produces a diploid zygote from two haploid gametes
- (C) It takes place in the ovary
- (D) It produces four haploid cells at once
Show Answer
Answer: B – A haploid sperm fuses with a haploid egg cell to form a diploid zygote, usually in the oviduct.
Q45. Which method of asexual reproduction in plants involves a new plant growing from a stem that bends down and touches the soil?
- (A) Binary fission
- (B) Spore formation
- (C) Seed dispersal
- (D) Layering
Show Answer
Answer: D – In layering, a stem in contact with soil forms roots and later grows as an independent plant genetically identical to the parent.
Inheritance
Q46. In a monohybrid cross between two heterozygous parents (Tt x Tt), what proportion of the offspring is expected to show the recessive trait?
- (A) All of them
- (B) Three quarters
- (C) One half
- (D) One quarter
Show Answer
Answer: D – The cross gives genotypes TT, Tt, Tt and tt, so only the tt offspring, one quarter, show the recessive trait.
Q47. What is meant by a dominant allele?
- (A) An allele that is expressed even when only one copy is present
- (B) An allele that only shows its effect when two identical copies are inherited together
- (C) A complete set of chromosomes
- (D) A cell produced by meiosis
Show Answer
Answer: A – A dominant allele masks the recessive allele in a heterozygous organism, so its trait is shown.
Q48. A child has blood group O, while both parents have blood group A. What can be concluded about the parents?
- (A) Both parents must be homozygous for group A
- (B) The child inherited a new mutation
- (C) Both parents carry a recessive O allele
- (D) Blood group is not inherited
Show Answer
Answer: C – For the child to be OO, each parent must have passed on an O allele, so each parent is heterozygous AO.
Variation and selection
Q49. Which type of variation is caused only by the environment and cannot be inherited?
- (A) A scar gained from an injury
- (B) Eye colour
- (C) Blood group
- (D) The shape of an earlobe, which is inherited from parents
Show Answer
Answer: A – Environmental variation, such as a scar, affects the body during life but does not change the genes passed to offspring.
Q50. How does natural selection lead to antibiotic resistance in bacteria?
- (A) Antibiotics teach bacteria to make new genes
- (B) All bacteria mutate in the same way when exposed
- (C) Resistant bacteria survive, reproduce and pass on their resistance genes
- (D) Antibiotics directly change the bacterial chromosome
Show Answer
Answer: C – Variation already exists in the population, and the antibiotic selects for the resistant variants, which then increase in frequency.
Q51. Which statement best describes continuous variation?
- (A) It shows only two or three distinct phenotypes
- (B) It is controlled by a single gene only
- (C) It is unaffected by the environment
- (D) It shows a range of values with no clear categories
Show Answer
Answer: D – Traits such as height show continuous variation, with individuals spread across a range rather than falling into groups.
Organisms and their environment
Q52. In a food web, which organisms are always the producers?
- (A) Herbivores, which eat plants for energy
- (B) Green plants
- (C) Decomposers
- (D) Carnivores
Show Answer
Answer: B – Green plants trap light energy and make food by photosynthesis, forming the base of almost every food web.
Q53. Why is only a small proportion of energy passed from one trophic level to the next?
- (A) Energy is destroyed during feeding
- (B) Much energy is lost in respiration, movement, excretion and egestion
- (C) Producers store no energy at all
- (D) Herbivores eat only a tiny fraction of plants
Show Answer
Answer: B – At each level, energy is lost as heat in respiration and in waste materials, so less remains for the next level.
Q54. Which pyramid always has the same shape, with the producer bar widest at the base?
- (A) Pyramid of energy
- (B) Pyramid of numbers for a tree food chain
- (C) Pyramid of biomass for a tree food chain
- (D) Pyramid of numbers for a parasite food chain
Show Answer
Answer: A – Energy is always lost between levels, so a pyramid of energy is always upright, unlike pyramids of numbers or biomass.
Human influences on ecosystems
Q55. How does untreated sewage entering a river most directly harm aquatic life?
- (A) It cools the water sharply
- (B) It adds oxygen to the water
- (C) Bacteria decomposing it use up dissolved oxygen
- (D) It makes the water clearer
Show Answer
Answer: C – Decomposer bacteria multiply on the sewage and consume oxygen during respiration, which can suffocate fish and other organisms.
Q56. Which gas, released by burning fossil fuels, is the main contributor to the enhanced greenhouse effect?
- (A) Oxygen
- (B) Nitrogen, which makes up most of the atmosphere
- (C) Hydrogen
- (D) Carbon dioxide
Show Answer
Answer: D – Carbon dioxide traps heat radiated from Earth, and rising levels from fossil fuel burning strengthen the greenhouse effect.
Q57. Deforestation for farming is most likely to have which immediate effect on the local environment?
- (A) Increased rainfall every day
- (B) More habitats for forest species
- (C) Greater soil fertility for decades
- (D) Loss of habitats and increased soil erosion
Show Answer
Answer: D – Removing trees destroys habitats and leaves soil exposed, so it is washed away more easily by rain.
Biotechnology and genetic modification
Q58. In genetic modification, what is a plasmid used for in bacteria?
- (A) To kill the bacteria after modification
- (B) To carry a foreign gene into the bacterial cell
- (C) To supply oxygen for respiration
- (D) To digest the bacterial chromosome
Show Answer
Answer: B – A plasmid is a small circular piece of DNA that can carry a desired gene into a bacterium, which then makes the gene product.
Q59. Why is insulin produced by genetically modified bacteria useful in medicine?
- (A) It is human insulin, made in large amounts without using animal tissue
- (B) It works only in patients with type 1 diabetes for one day
- (C) It replaces the need for any blood glucose testing
- (D) It cures diabetes permanently after one dose
Show Answer
Answer: A – Bacteria with the human insulin gene can produce large quantities of identical human insulin quickly and cheaply.
Q60. Which concern is commonly raised about genetically modified crops?
- (A) They always produce less food than unmodified crops
- (B) They cannot be grown outside a laboratory
- (C) Modified genes might spread to wild relatives
- (D) They contain no DNA at all
Show Answer
Answer: C – One concern is gene flow, where pollen from a modified crop could transfer the modified gene to related wild plants.
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