IGCSE Biology Practice Test 6 – 60 Questions with Answers (Cambridge 0610)
This test revisits every major topic in the course, so use it to find the areas that still need a little more revision.
Characteristics and classification of living organisms
Q1. Which life process involves the removal of waste products made inside an organism?
- (A) Nutrition
- (B) Excretion
- (C) Sensitivity
- (D) Reproduction
Show Answer
Answer: B – Excretion is the removal of toxic metabolic waste products from an organism.
Q2. A student observes an organism with jointed legs, a hard exoskeleton and three body sections. To which group does it belong?
- (A) Annelids
- (B) Molluscs
- (C) Cnidarians
- (D) Arthropods
Show Answer
Answer: D – Arthropods have jointed limbs and an exoskeleton, and insects have three body sections.
Q3. Which feature is found in both plant cells and animal cells?
- (A) A nucleus
- (B) A chloroplast
- (C) A large permanent vacuole
- (D) A cellulose cell wall
Show Answer
Answer: A – Both plant and animal cells contain a nucleus, cytoplasm and a cell membrane.
Organisation of the organism
Q4. Which sequence correctly orders levels of organisation from smallest to largest?
- (A) Organ, tissue, cell, system
- (B) System, organ, tissue, cell
- (C) Cell, tissue, organ, system
- (D) Tissue, cell, system, organ
Show Answer
Answer: C – Cells form tissues, tissues form organs, and organs work together in systems.
Q5. Which tissue carries out most photosynthesis in a leaf?
- (A) Palisade mesophyll
- (B) Upper epidermis
- (C) Xylem vessels in the leaf
- (D) Lower epidermis
Show Answer
Answer: A – Palisade cells contain many chloroplasts and are packed near the upper leaf surface.
Q6. Which level of organisation is formed when different tissues work together?
- (A) Cell
- (B) Tissue
- (C) System
- (D) Organ
Show Answer
Answer: D – An organ is made of different tissues working together to carry out a particular function.
Movement into and out of cells
Q7. By which process does oxygen move from an alveolus into a blood capillary?
- (A) Active transport
- (B) Diffusion
- (C) Osmosis
- (D) Transpiration
Show Answer
Answer: B – Oxygen diffuses down its concentration gradient across the thin alveolar wall.
Q8. What happens to a red blood cell placed in pure water?
- (A) It becomes turgid but does not burst because its cell wall resists the pressure
- (B) It shrinks as water leaves by osmosis
- (C) It swells and bursts because water enters by osmosis
- (D) It stays unchanged because water cannot cross the membrane
Show Answer
Answer: C – Water enters the cell by osmosis, and with no cell wall to resist the pressure, the cell bursts.
Q9. Which statement about diffusion is correct?
- (A) It moves particles from higher to lower concentration without using energy
- (B) It moves particles against a concentration gradient and requires energy from respiration
- (C) It only moves water across a partially permeable membrane
- (D) It only occurs in root hair cells
Show Answer
Answer: A – Diffusion is the net movement of particles down a concentration gradient, and it needs no energy input from the cell.
Biological molecules
Q10. Which test is used to detect starch in a food sample?
- (A) Benedict’s test, which is heated with the sample and gives a brick-red precipitate
- (B) Iodine test
- (C) Biuret test
- (D) Emulsion test with ethanol
Show Answer
Answer: B – Iodine solution turns from brown to blue-black when starch is present in a sample.
Q11. Which molecule is a polysaccharide used for energy storage in plants?
- (A) Glucose
- (B) Amino acid
- (C) Glycerol
- (D) Starch
Show Answer
Answer: D – Starch is a large insoluble carbohydrate that plants store in seeds, roots and leaves.
Q12. A fat molecule is made from glycerol and which other component?
- (A) Glucose units
- (B) Amino acids
- (C) Fatty acids
- (D) Nucleotides
Show Answer
Answer: C – One glycerol molecule combines with three fatty acid molecules to form a fat.
Enzymes
Q13. What happens to most human enzymes when the temperature rises well above the optimum?
- (A) They work faster and faster without any limit
- (B) They become more specific
- (C) They are denatured and lose their shape
- (D) They are used up in the reaction
Show Answer
Answer: C – High temperature breaks bonds in the enzyme, changing the active site so the substrate no longer fits.
Q14. Which enzyme breaks down starch in the mouth?
- (A) Amylase
- (B) Protease
- (C) Lipase
- (D) Catalase
Show Answer
Answer: A – Salivary amylase hydrolyses starch into smaller sugars such as maltose.
Q15. At a low temperature, why is enzyme activity slow?
- (A) The enzymes are denatured
- (B) The substrate is used up quickly and cannot be replaced
- (C) The enzymes are destroyed by cold
- (D) Particles move slowly, so there are fewer collisions
Show Answer
Answer: D – At low temperatures molecules have less kinetic energy, so enzyme and substrate collide less often.
Plant nutrition
Q16. Which substance is needed by a plant for photosynthesis, in addition to water and light energy?
- (A) Oxygen
- (B) Carbon dioxide
- (C) Glucose
- (D) Nitrate ions from the soil
Show Answer
Answer: B – Carbon dioxide from the air combines with water in photosynthesis to make glucose.
Q17. A plant kept in darkness for two days is tested with iodine solution. What result is expected in its leaves?
- (A) Blue-black colour throughout
- (B) Brick-red precipitate
- (C) Purple colour in the veins
- (D) Brown colour, showing no starch present
Show Answer
Answer: D – Without light there is no photosynthesis, so stored starch is used up and iodine stays brown.
Q18. Which mineral ion is needed to make chlorophyll?
- (A) Nitrate ions
- (B) Phosphate ions
- (C) Magnesium ions
- (D) Potassium ions
Show Answer
Answer: C – Magnesium is a central part of the chlorophyll molecule, so deficiency causes yellow leaves.
Human nutrition
Q19. Where in the human gut is most digested food absorbed into the blood?
- (A) Ileum
- (B) Stomach
- (C) Colon
- (D) Rectum
Show Answer
Answer: A – The ileum has villi that give a large surface area for absorption into capillaries.
Q20. Which mineral is needed to make haemoglobin in red blood cells?
- (A) Calcium
- (B) Iron
- (C) Iodine
- (D) Potassium
Show Answer
Answer: B – Iron is a key part of haemoglobin, which carries oxygen in red blood cells.
Q21. A diet lacking fibre is most likely to cause which problem?
- (A) Scurvy
- (B) Rickets
- (C) Constipation
- (D) Anaemia caused by iron deficiency
Show Answer
Answer: C – Fibre adds bulk and helps food move through the gut, preventing constipation.
Transport in plants
Q22. Which force pulls water up a plant stem in the transpiration stream?
- (A) Root pressure, which pushes water upwards from the roots into the xylem vessels
- (B) Capillarity in the soil
- (C) Active transport in leaves
- (D) Transpiration pull
Show Answer
Answer: D – Evaporation from the leaves pulls a continuous column of water up through the xylem.
Q23. Which factor decreases the rate of transpiration?
- (A) High humidity
- (B) Wind
- (C) High temperature
- (D) Bright light
Show Answer
Answer: A – Humid air reduces the water vapour gradient, so less water diffuses out of the leaf.
Q24. Which statement describes translocation in a plant?
- (A) Water moves up in xylem vessels to the leaves
- (B) Sucrose moves in phloem from source to sink
- (C) Mineral ions move into root hair cells
- (D) Water vapour leaves through stomata
Show Answer
Answer: B – Translocation is the movement of sucrose and amino acids in phloem to growing or storage regions.
Transport in animals
Q25. In the human heart, which vessel carries oxygenated blood away from the heart to the body?
- (A) Pulmonary artery
- (B) Vena cava
- (C) Pulmonary vein
- (D) Aorta
Show Answer
Answer: D – The aorta is the large artery that carries oxygenated blood from the left ventricle to the body.
Q26. Which blood vessel carries blood back to the heart at low pressure?
- (A) Artery
- (B) Vein
- (C) Capillary
- (D) Lymph duct
Show Answer
Answer: B – Veins return blood to the heart at low pressure and contain valves to prevent backflow.
Q27. What is the main function of valves in veins?
- (A) To increase blood pressure
- (B) To filter the blood
- (C) To prevent backflow of blood
- (D) To carry oxygen to tissues
Show Answer
Answer: C – Veins are low pressure, so valves stop blood flowing backwards between heartbeats.
Diseases and immunity
Q28. Which type of pathogen causes athlete’s foot?
- (A) Fungus
- (B) Virus, a non-living particle that must reproduce inside a host cell
- (C) Bacterium
- (D) Protoctist
Show Answer
Answer: A – Athlete’s foot is a fungal infection of the skin, usually between the toes.
Q29. Which cells produce antibodies during an immune response?
- (A) Red blood cells
- (B) Lymphocytes
- (C) Platelets
- (D) Muscle cells
Show Answer
Answer: B – Lymphocytes produce specific antibodies that bind to antigens on pathogens.
Q30. Which defence is a chemical barrier against pathogens entering the body?
- (A) Hydrochloric acid in the stomach
- (B) Skin
- (C) Mucus trapping particles
- (D) Blood clotting at a wound
Show Answer
Answer: A – Stomach acid kills many pathogens in food, while skin and mucus are physical barriers.
Gas exchange in humans
Q31. Which feature of alveoli most increases the rate of gas exchange?
- (A) Thick walls
- (B) Small number of air sacs
- (C) Dry inner surface
- (D) Large surface area and rich blood supply
Show Answer
Answer: D – Millions of thin-walled alveoli give a huge surface area close to capillaries for rapid diffusion.
Q32. During exhalation, what happens to the diaphragm and the ribcage?
- (A) Diaphragm contracts and flattens while the ribs move up and out to increase chest volume
- (B) Diaphragm contracts and ribs move down
- (C) Diaphragm relaxes and ribs move down and in
- (D) Diaphragm relaxes and ribs move up
Show Answer
Answer: C – The diaphragm domes upwards and the ribs fall, reducing chest volume and forcing air out of the lungs.
Q33. Why is the diaphragm important in breathing?
- (A) It produces mucus to trap dust
- (B) It contracts to increase chest volume for inhalation
- (C) It filters oxygen from the air
- (D) It carries oxygen to the blood
Show Answer
Answer: B – When the diaphragm contracts and flattens, chest volume increases and air is drawn into the lungs.
Respiration
Q34. Which product of anaerobic respiration in yeast is used to make bread rise?
- (A) Lactic acid, which builds up in muscles during vigorous exercise
- (B) Ethanol
- (C) Water
- (D) Carbon dioxide
Show Answer
Answer: D – Carbon dioxide released by fermenting yeast forms bubbles that make dough rise.
Q35. Why does anaerobic respiration in muscle produce less energy per glucose molecule than aerobic respiration?
- (A) Glucose is only partly broken down to lactic acid
- (B) No glucose is used at all
- (C) Oxygen is stored in the muscle
- (D) Lactic acid releases extra energy later
Show Answer
Answer: A – Incomplete breakdown leaves much chemical energy still stored in lactic acid.
Q36. After vigorous exercise, why does breathing stay rapid for a time?
- (A) To replace lost water
- (B) To cool the skin
- (C) To supply oxygen to break down lactic acid
- (D) To remove excess glucose
Show Answer
Answer: C – Extra oxygen is needed to oxidise lactic acid, repaying the oxygen debt.
Excretion in humans
Q37. Which structure carries urine out of the body from the bladder?
- (A) Urethra
- (B) Ureter, which carries urine from each kidney down into the bladder
- (C) Renal artery
- (D) Renal vein
Show Answer
Answer: A – The urethra carries urine from the bladder out of the body, controlled by a sphincter muscle.
Q38. In a kidney tubule, which substance is selectively reabsorbed in large amounts when the body needs water?
- (A) Urea
- (B) Salt only
- (C) Water
- (D) Glucose only in diabetes
Show Answer
Answer: C – Antidiuretic hormone increases water reabsorption from the collecting ducts when the body is short of water.
Q39. Which organ is mainly responsible for removing urea from the blood?
- (A) Liver
- (B) Kidney
- (C) Lung
- (D) Skin
Show Answer
Answer: B – The liver makes urea, but the kidneys filter it from blood and excrete it in urine.
Coordination and response
Q40. In a reflex arc, which neurone carries impulses from the receptor towards the central nervous system?
- (A) Motor neurone
- (B) Relay neurone
- (C) Effector neurone
- (D) Sensory neurone
Show Answer
Answer: D – Sensory neurones carry impulses from receptors to the spinal cord or brain.
Q41. Which hormone is released when blood glucose concentration falls too low?
- (A) Insulin
- (B) Adrenaline
- (C) Glucagon
- (D) Thyroxine
Show Answer
Answer: C – Glucagon stimulates the liver to convert glycogen to glucose, raising blood glucose.
Q42. Which structure controls the size of the pupil?
- (A) Cornea, the transparent front layer that refracts light into the eye
- (B) Retina
- (C) Lens
- (D) Iris
Show Answer
Answer: D – Muscles in the iris adjust the pupil diameter to control how much light enters the eye.
Drugs
Q43. Which substance in tobacco smoke binds to haemoglobin and reduces oxygen transport?
- (A) Carbon monoxide
- (B) Nicotine, the addictive substance that makes the heart beat faster and narrows vessels
- (C) Tar
- (D) Smoke particles
Show Answer
Answer: A – Carbon monoxide binds to haemoglobin more readily than oxygen, reducing the oxygen carried in the blood.
Q44. Why can antibiotics not cure a common cold?
- (A) The cold virus hides inside red blood cells
- (B) Antibiotics kill bacteria, not viruses
- (C) The immune system blocks antibiotics
- (D) Cold viruses are resistant to all medicines
Show Answer
Answer: B – Colds are caused by viruses, which antibiotics do not affect.
Q45. Which statement about solvents is correct?
- (A) They are stimulants that increase alertness and speed up reactions in the nervous system
- (B) They are antibiotics used against infection
- (C) They are painkillers with no side effects
- (D) They are depressants that can damage the liver and nervous system
Show Answer
Answer: D – Inhaling solvents depresses the nervous system and can cause serious damage to the liver, kidneys and brain.
Reproduction
Q46. Which part of a flower becomes the seed after fertilisation?
- (A) Ovule
- (B) Style
- (C) Petal
- (D) Sepal
Show Answer
Answer: A – After fertilisation, the ovule develops into a seed containing the embryo and a food store.
Q47. In humans, where does fertilisation normally take place?
- (A) Uterus
- (B) Ovary
- (C) Oviduct
- (D) Cervix
Show Answer
Answer: C – A sperm normally fertilises an egg in the oviduct, and the zygote then moves to the uterus.
Inheritance
Q48. A gene for tall plants (T) is dominant over short plants (t). What is the phenotype of a Tt plant?
- (A) Short
- (B) Tall
- (C) Medium height
- (D) Cannot be predicted
Show Answer
Answer: B – The dominant allele T is expressed in the heterozygous genotype, so the plant is tall.
Q49. Which sex chromosomes are found in a human male?
- (A) XX
- (B) XO
- (C) XXX
- (D) XY
Show Answer
Answer: D – Females have XX sex chromosomes and males have XY.
Variation and selection
Q50. Which type of variation is mainly caused by genes and shows distinct categories?
- (A) Discontinuous variation
- (B) Continuous variation
- (C) Environmental variation
- (D) Acquired variation
Show Answer
Answer: A – Discontinuous variation, such as blood group, is controlled by genes and falls into clear groups.
Q51. Which process increases variation in a population?
- (A) Cloning
- (B) Asexual reproduction
- (C) Mutation
- (D) Selective breeding for one trait
Show Answer
Answer: C – Mutations create new alleles, which can be passed on and increase genetic variation.
Organisms and their environment
Q52. What is a community?
- (A) A group of organisms of one species living together in one particular habitat
- (B) All the organisms of all species living in a habitat
- (C) A pyramid of numbers
- (D) A carbon cycle diagram
Show Answer
Answer: B – A community is all the populations of different species that live together in one habitat.
Q53. Why is a pyramid of biomass usually narrower at higher trophic levels?
- (A) Energy is lost at each transfer, so less biomass can be supported
- (B) Top predators eat more food than herbivores
- (C) Decomposers remove all biomass
- (D) Plants grow faster than animals
Show Answer
Answer: A – Energy is lost through respiration, excretion and egestion, so each level supports less biomass.
Q54. Which organism is both a producer and part of the carbon cycle?
- (A) A rabbit
- (B) A green plant
- (C) A fungus
- (D) A bacterium in soil
Show Answer
Answer: B – Green plants photosynthesise, taking in carbon dioxide and fixing carbon into organic compounds.
Human influences on ecosystems
Q55. Which human activity most directly causes habitat destruction for orangutans?
- (A) Overfishing in oceans
- (B) Recycling paper
- (C) Using solar power
- (D) Clearing rainforest for palm oil plantations
Show Answer
Answer: D – Deforestation removes the forest habitat and food sources on which orangutans depend.
Q56. What is global warming?
- (A) A thinning of the ozone layer caused by chlorofluorocarbons released from old aerosols
- (B) The warming of oceans by the Sun
- (C) A rise in average Earth temperatures caused by increased greenhouse gases
- (D) The removal of fish by predators
Show Answer
Answer: C – Increased carbon dioxide and methane trap more heat, raising average global temperatures over time.
Q57. Which gas is the main cause of increased global warming from burning fossil fuels?
- (A) Oxygen
- (B) Nitrogen
- (C) Carbon dioxide
- (D) Argon
Show Answer
Answer: C – Carbon dioxide traps heat in the atmosphere, raising global temperatures.
Biotechnology and genetic modification
Q58. In genetic modification, what is a plasmid commonly used for?
- (A) To kill bacteria
- (B) To produce antibodies
- (C) To store starch
- (D) To carry a desired gene into a bacterial cell
Show Answer
Answer: D – A plasmid vector is cut open, a gene is inserted, and the recombinant plasmid is taken up by bacteria.
Q59. Which is a benefit of genetically modifying crops to resist pests?
- (A) Less insecticide is needed
- (B) Crops need more water
- (C) Yields always fall
- (D) Soil nutrients are removed faster
Show Answer
Answer: A – Pest-resistant crops suffer less damage, so farmers can spray less insecticide.
Q60. Which product is made by genetically modifying crops?
- (A) Bread, which is made using yeast fermentation in dough left to rise
- (B) Herbicide-resistant soya beans
- (C) Fruit juice
- (D) Cheese curd
Show Answer
Answer: B – Soya beans can be modified with a gene for herbicide resistance so weeds can be controlled without harming the crop.
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