IGCSE Biology Practice Test 7 – 60 Questions with Answers (Cambridge 0610)
Work through this test under timed conditions if you can, then check each answer and note any topic you need to revisit.
Characteristics and classification of living organisms
Q1. Which life process allows an organism to detect and respond to changes in its surroundings?
- (A) Growth
- (B) Movement
- (C) Nutrition from food sources
- (D) Sensitivity
Show Answer
Answer: D – Sensitivity is the ability to detect stimuli and make appropriate responses.
Q2. Which kingdom contains organisms that are single-celled, have a nucleus, and are not plants, animals or fungi?
- (A) Prokaryotes
- (B) Protoctists
- (C) Plantae
- (D) Animalia
Show Answer
Answer: B – Protoctists are mostly single-celled eukaryotes, such as Amoeba and Chlorella.
Q3. Which pair of features is used to place an animal in the vertebrate group?
- (A) Jointed legs and wings for flight
- (B) Soft body and shell
- (C) Backbone and internal skeleton
- (D) Segmented body and bristles
Show Answer
Answer: C – Vertebrates have a backbone made of vertebrae protecting the spinal cord.
Organisation of the organism
Q4. Which organ system transports blood around the human body?
- (A) Circulatory system
- (B) Respiratory system
- (C) Digestive system
- (D) Nervous system
Show Answer
Answer: A – The heart, blood and blood vessels together form the circulatory system.
Q5. A ciliated epithelial cell is adapted for its job mainly by having which feature?
- (A) A large permanent vacuole for storage
- (B) Tiny hair-like cilia that move mucus
- (C) Many chloroplasts
- (D) A thick cellulose wall
Show Answer
Answer: B – Beating cilia sweep mucus and trapped particles away from the lungs.
Q6. Which structure is an example of an organ in a flowering plant?
- (A) Leaf
- (B) Palisade cell
- (C) Chloroplast
- (D) Xylem vessel
Show Answer
Answer: A – A leaf is an organ made of several tissues working together for photosynthesis.
Movement into and out of cells
Q7. A red blood cell placed in distilled water will swell and burst because of which process?
- (A) Diffusion of salts out of the cell
- (B) Active transport of water
- (C) Digestion of the membrane
- (D) Osmosis of water into the cell
Show Answer
Answer: D – Water moves by osmosis into the cell, which has no rigid wall to resist bursting.
Q8. Which condition gives the fastest rate of diffusion of a gas?
- (A) A small surface area for diffusion
- (B) A long diffusion distance
- (C) A large concentration difference
- (D) A low temperature
Show Answer
Answer: C – A steep concentration gradient increases the net movement of particles by diffusion.
Q9. Root hair cells absorb mineral ions from very dilute soil water mainly by which process?
- (A) Osmosis
- (B) Active transport
- (C) Diffusion only
- (D) Transpiration pull
Show Answer
Answer: B – Active transport uses energy to take ions up against their concentration gradient.
Biological molecules
Q10. Which food test turns purple in the presence of protein?
- (A) Benedict’s test
- (B) Iodine test
- (C) Emulsion test
- (D) Biuret test
Show Answer
Answer: D – Biuret solution changes from blue to purple when protein is present.
Q11. What are proteins made from?
- (A) Amino acids
- (B) Fatty acids and glycerol
- (C) Simple sugars
- (D) Nucleotides
Show Answer
Answer: A – Amino acids join in long chains that fold into protein molecules.
Q12. Which statement about glycogen is correct?
- (A) It is a protein stored in muscles and used for growth
- (B) It is a fat stored in seeds
- (C) It is a carbohydrate stored in liver and muscle
- (D) It is a vitamin found in milk
Show Answer
Answer: C – Animals store glucose as glycogen, mainly in the liver and in muscle cells.
Enzymes
Q13. Which model best describes how an enzyme and substrate interact?
- (A) The substrate changes the enzyme permanently during the reaction
- (B) Lock and key, with the substrate fitting the active site
- (C) The enzyme is broken down with the substrate
- (D) The substrate dissolves the enzyme
Show Answer
Answer: B – The substrate fits the shape of the active site, forming an enzyme-substrate complex.
Q14. Which enzyme is found in the stomach and works best in acid conditions?
- (A) Amylase
- (B) Lipase
- (C) Trypsin
- (D) Pepsin
Show Answer
Answer: D – Pepsin is a protease secreted in the stomach, where the pH is about 2.
Q15. What happens to the rate of an enzyme-controlled reaction as substrate concentration increases, until all active sites are full?
- (A) It increases
- (B) It decreases steadily
- (C) It stays at zero
- (D) It becomes negative
Show Answer
Answer: A – More substrate means more frequent collisions, until the enzyme is saturated and the rate levels off.
Plant nutrition
Q16. Which factor limits the rate of photosynthesis when light intensity and temperature are both high?
- (A) Oxygen concentration
- (B) Soil pH
- (C) Carbon dioxide concentration
- (D) Water loss from leaves by transpiration
Show Answer
Answer: C – When other factors are plentiful, carbon dioxide supply becomes the limiting factor.
Q17. A leaf is tested for starch after being kept in light. Which part gives a blue-black result with iodine?
- (A) The green part that was exposed to light
- (B) A part covered with black paper to block light
- (C) A variegated white part
- (D) The midrib only
Show Answer
Answer: A – Only chlorophyll-containing tissue exposed to light photosynthesises and stores starch.
Q18. A plant shows poor growth and old leaves turn yellow first. Which deficiency is most likely?
- (A) Calcium deficiency
- (B) Iron deficiency
- (C) Potassium deficiency
- (D) Nitrate deficiency
Show Answer
Answer: D – Nitrates are needed for proteins, and deficiency causes stunted growth and yellowing leaves.
Human nutrition
Q19. Which organ produces insulin and digestive enzymes?
- (A) Liver
- (B) Pancreas
- (C) Gall bladder
- (D) Spleen
Show Answer
Answer: B – The pancreas secretes enzymes into the duodenum and insulin into the blood.
Q20. Which nutrient deficiency causes scurvy?
- (A) Lack of iron
- (B) Lack of calcium
- (C) Lack of vitamin C
- (D) Lack of vitamin D
Show Answer
Answer: C – Vitamin C is needed for healthy skin, gums and blood vessels, and its lack causes scurvy.
Q21. Which adaptation of a villus helps absorption?
- (A) A single layer of thin cells and a rich capillary network
- (B) A thick wall and few blood vessels, slowing absorption greatly
- (C) A large vacuole and chloroplasts
- (D) A waterproof cuticle
Show Answer
Answer: A – A thin wall shortens the diffusion distance and capillaries carry absorbed nutrients away quickly.
Transport in plants
Q22. Which process explains how water moves up a tall tree in xylem?
- (A) Active transport by roots
- (B) Transpiration pull
- (C) Diffusion through phloem
- (D) Osmosis from leaves
Show Answer
Answer: B – Water lost from leaves pulls a continuous column of water up through xylem vessels.
Q23. A potometer is used to measure which quantity?
- (A) Rate of photosynthesis in the leaves
- (B) Rate of respiration
- (C) Rate of growth
- (D) Rate of water uptake by a shoot
Show Answer
Answer: D – A potometer measures water uptake, which is used as an estimate of transpiration rate.
Q24. How does water move through xylem vessels?
- (A) By active transport, using energy from respiration in the root hair cells
- (B) By diffusion through living cells
- (C) By transpiration pull up the stem
- (D) By gravity alone, flowing downwards
Show Answer
Answer: C – Water lost from leaves pulls a continuous column of water up the dead, hollow xylem vessels.
Transport in animals
Q25. Which chamber of the heart pumps blood to the lungs?
- (A) Left atrium
- (B) Left ventricle of the heart
- (C) Right atrium
- (D) Right ventricle
Show Answer
Answer: D – The right ventricle pumps deoxygenated blood through the pulmonary artery to the lungs.
Q26. Which vessel carries blood from the lungs back to the heart?
- (A) Pulmonary vein
- (B) Pulmonary artery
- (C) Hepatic vein
- (D) Renal artery
Show Answer
Answer: A – The pulmonary vein is unusual because it carries oxygenated blood towards the heart.
Q27. Which feature of arteries helps them withstand high pressure?
- (A) Valves throughout the vessel to prevent backflow
- (B) Thin walls
- (C) Thick muscular and elastic walls
- (D) Large lumen only
Show Answer
Answer: C – Thick elastic walls stretch and recoil, smoothing the pulse of blood from the heart.
Diseases and immunity
Q28. Which disease is caused by a bacterium and spread in droplets when an infected person coughs?
- (A) Influenza caused by a virus
- (B) Tuberculosis
- (C) Malaria
- (D) Cholera
Show Answer
Answer: B – Tuberculosis is caused by a bacterium and spreads through the air in droplets from coughs.
Q29. Why is a booster dose of a vaccine sometimes given?
- (A) To strengthen the memory cell response so protection lasts longer
- (B) To provide ready-made antibodies from another organism for immediate short-term protection
- (C) To kill all pathogens in the body at once
- (D) To replace antibiotics taken during illness
Show Answer
Answer: A – A booster re-exposes the immune system to the antigen, increasing memory cell numbers and extending protection.
Q30. Which white blood cell action destroys pathogens by engulfing them?
- (A) Antibody production
- (B) Phagocytosis
- (C) Clotting
- (D) Memory cell formation
Show Answer
Answer: B – Phagocytes engulf pathogens and digest them with enzymes.
Gas exchange in humans
Q31. Which structure prevents food entering the trachea during swallowing?
- (A) Bronchus
- (B) Alveolus
- (C) Diaphragm
- (D) Epiglottis
Show Answer
Answer: D – The epiglottis is a flap of cartilage that closes over the trachea when swallowing.
Q32. Why are alveolar walls only one cell thick?
- (A) To store air
- (B) To produce mucus
- (C) To shorten the diffusion distance for gases
- (D) To prevent water loss
Show Answer
Answer: C – A thin wall lets oxygen and carbon dioxide diffuse rapidly between air and blood.
Q33. During exhalation, which change occurs in the thorax?
- (A) Ribs move up and diaphragm flattens
- (B) Volume increases and pressure falls
- (C) Volume decreases and air pressure rises
- (D) Intercostal muscles contract strongly
Show Answer
Answer: C – Muscles relax, the chest volume falls, pressure rises above air pressure, and air is forced out.
Respiration
Q34. Which process releases energy from glucose without using oxygen in yeast?
- (A) Photosynthesis
- (B) Aerobic respiration
- (C) Digestion
- (D) Anaerobic respiration
Show Answer
Answer: D – Yeast respires anaerobically to produce ethanol and carbon dioxide, releasing some energy.
Q35. Which word equation shows anaerobic respiration in yeast?
- (A) Glucose to ethanol plus carbon dioxide
- (B) Glucose plus oxygen to carbon dioxide plus water
- (C) Glucose to lactic acid
- (D) Carbon dioxide plus water to glucose plus oxygen
Show Answer
Answer: A – Yeast breaks glucose down to ethanol and carbon dioxide when oxygen is absent.
Q36. Which use of energy released by respiration occurs in a growing root tip?
- (A) Muscle contraction
- (B) Active transport of ions into cells
- (C) Keeping the body warm
- (D) Movement of the whole plant
Show Answer
Answer: B – Respiration provides energy for active transport, cell division and building new molecules.
Excretion in humans
Q37. Which process in the kidney removes small molecules from blood into the tubule?
- (A) Reabsorption
- (B) Secretion of urea only
- (C) Ultrafiltration
- (D) Digestion
Show Answer
Answer: C – High pressure forces water, salts, glucose and urea through the glomerulus filter into the capsule.
Q38. Which substance is normally found in the urine of a healthy person?
- (A) Urea
- (B) Glucose, which is filtered from the blood but normally reabsorbed in the kidney tubules
- (C) Protein
- (D) Red blood cells
Show Answer
Answer: A – Urea made in the liver is filtered from the blood and excreted in urine, along with water and excess salts.
Q39. Where does deamination take place?
- (A) Kidney, which filters the blood and removes urea from the body as urine
- (B) Pancreas
- (C) Spleen
- (D) Liver
Show Answer
Answer: D – In the liver, excess amino acids are broken down and their nitrogen-containing part is converted to urea.
Coordination and response
Q40. What is the role of a receptor in a reflex?
- (A) It carries impulses away from the central nervous system
- (B) It detects a stimulus and starts an impulse
- (C) It contracts a muscle to produce a response
- (D) It secretes a hormone into the blood
Show Answer
Answer: B – A receptor detects a change in the environment and triggers an impulse in a sensory neurone.
Q41. What does adrenaline prepare the body for?
- (A) Sleep and rest
- (B) Digestion after a meal
- (C) Growth during childhood
- (D) Fight or flight by raising heart rate and blood glucose
Show Answer
Answer: D – Adrenaline increases heart rate, breathing rate and glucose release for rapid action.
Q42. In the eye, which structure controls the size of the pupil?
- (A) Lens
- (B) Retina
- (C) Iris
- (D) Cornea
Show Answer
Answer: C – Muscles in the iris adjust the pupil diameter to control how much light enters.
Drugs
Q43. Which substance in tobacco smoke combines with haemoglobin and reduces oxygen transport?
- (A) Carbon monoxide
- (B) Nicotine
- (C) Tar
- (D) Water vapour
Show Answer
Answer: A – Carbon monoxide binds haemoglobin more strongly than oxygen, forming carboxyhaemoglobin.
Q44. Which effect does smoking have on the lungs?
- (A) It improves the ability of alveoli to exchange gases by clearing mucus from the airways
- (B) It damages cilia and increases mucus, raising the risk of bronchitis
- (C) It increases oxygen transport
- (D) It has no effect on the airways
Show Answer
Answer: B – Smoke paralyses cilia and irritates airways, so mucus builds up and infections become more likely.
Q45. Why is sharing needles a risk for people who inject drugs?
- (A) It causes immediate addiction
- (B) It increases appetite
- (C) It can spread blood-borne infections such as HIV
- (D) It reduces heart rate permanently
Show Answer
Answer: C – Contaminated needles can pass infected blood between users, spreading HIV and hepatitis.
Reproduction
Q46. Which structure in a flower receives pollen during pollination?
- (A) Ovary
- (B) Anther
- (C) Sepal
- (D) Stigma
Show Answer
Answer: D – The stigma is the sticky top of the carpel that traps pollen grains during pollination.
Q47. In a flowering plant, what happens at pollination?
- (A) Pollen is transferred to the stigma
- (B) A seed germinates
- (C) The ovary ripens into a fruit
- (D) The pollen nucleus fuses with the egg
Show Answer
Answer: A – Pollination is transfer of pollen to the stigma; fusion of gametes is fertilisation.
Q48. Which human reproductive structure produces eggs?
- (A) Uterus
- (B) Ovary
- (C) Oviduct
- (D) Vagina
Show Answer
Answer: B – Ovaries contain follicles that release eggs at ovulation.
Inheritance
Q49. Which term describes the alleles an organism has for a particular gene?
- (A) Genotype
- (B) Phenotype
- (C) Allele frequency
- (D) Mutation
Show Answer
Answer: A – Genotype is the genetic make-up, while phenotype is the observable characteristic.
Q50. In a monohybrid cross between two heterozygous parents (Aa x Aa), what fraction of offspring is expected to show the recessive phenotype?
- (A) All of them
- (B) Three quarters
- (C) One quarter
- (D) None of them
Show Answer
Answer: C – The cross gives AA, Aa, Aa and aa, so one quarter shows the recessive trait.
Q51. Which statement about DNA is correct?
- (A) It is made of amino acids
- (B) It is a double helix carrying the genetic code
- (C) It is found only in gametes
- (D) It is broken down during mitosis
Show Answer
Answer: B – DNA is a double-stranded helix whose base sequence codes for proteins.
Variation and selection
Q52. Which characteristic shows discontinuous variation in humans?
- (A) Height, which varies gradually and is influenced by many genes and the environment
- (B) Body mass
- (C) Skin colour
- (D) Ability to roll the tongue
Show Answer
Answer: D – Tongue rolling falls into distinct categories, controlled by a single gene with little environmental influence.
Q53. In natural selection, which individuals are most likely to survive and reproduce?
- (A) The largest individuals
- (B) The oldest individuals
- (C) Those best adapted to the environment
- (D) Those that move the fastest
Show Answer
Answer: C – Better-adapted individuals pass their advantageous alleles to more offspring.
Q54. Which process is used in selective breeding?
- (A) Random mating with no human choice
- (B) Natural predators removing weak animals
- (C) Cloning by tissue culture only
- (D) Choosing parents with desired traits and breeding from them
Show Answer
Answer: D – Breeders select parents showing desired characteristics over many generations.
Organisms and their environment
Q55. In a food web, what happens if the number of herbivores falls sharply?
- (A) Producers increase and carnivores may decrease
- (B) Producers decrease and carnivores increase
- (C) Decomposers disappear completely
- (D) The Sun provides less energy
Show Answer
Answer: A – Fewer herbivores eat fewer plants, so producers increase, while carnivores lose food and may fall.
Q56. Which process returns carbon dioxide to the air in the carbon cycle?
- (A) Photosynthesis
- (B) Respiration
- (C) Feeding by herbivores
- (D) Formation of fossil fuels
Show Answer
Answer: B – Respiration by plants, animals and decomposers releases carbon dioxide into the atmosphere.
Human influences on ecosystems
Q57. Which practice helps protect endangered species?
- (A) Hunting animals without limits so that only the strongest individuals survive to breed
- (B) Destroying habitats for building
- (C) Introducing new predators
- (D) Creating protected reserves and breeding programmes
Show Answer
Answer: D – Reserves protect habitats and captive breeding can rebuild populations before release into the wild.
Q58. Which pollutant from vehicles contributes to acid rain?
- (A) Sulfur dioxide
- (B) Oxygen
- (C) Water vapour
- (D) Carbon monoxide only
Show Answer
Answer: A – Sulfur dioxide dissolves in rainwater to form acid rain, which damages trees and lakes.
Biotechnology and genetic modification
Q59. Which enzyme is used to cut DNA at a specific base sequence in genetic engineering?
- (A) Amylase
- (B) Ligase
- (C) Restriction enzyme
- (D) Protease
Show Answer
Answer: C – Restriction enzymes cut DNA at specific sequences, allowing a gene to be inserted.
Q60. Which concern is often raised about genetically modified crops?
- (A) They always taste better
- (B) Modified genes might spread to wild plants
- (C) They need no fertiliser at all
- (D) They cannot be grown outdoors
Show Answer
Answer: B – Gene flow to wild relatives is a debated environmental concern for modified crops.
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