IGCSE Biology Practice Test 1 – 60 Questions with Answers (Cambridge 0610)
This test covers the full IGCSE Biology syllabus in one sitting, so use it to find the topics that still need revision.
Characteristics and classification of living organisms
Q1. Which characteristic of living organisms involves the production of new individuals of the same kind?
- (A) Excretion
- (B) Reproduction
- (C) Sensitivity to stimuli in the surroundings
- (D) Nutrition
Show Answer
Answer: B – Reproduction is the process by which organisms produce offspring.
Q2. Which feature is shared by all five kingdoms?
- (A) Cells with a nucleus and membrane-bound organelles
- (B) Photosynthesis
- (C) Multicellular bodies
- (D) Cells surrounded by a membrane
Show Answer
Answer: D – Every living cell is bounded by a cell membrane, even in prokaryotes.
Organisation of the organism
Q3. Which sequence lists levels of organisation from simplest to most complex?
- (A) Cell, tissue, organ, organ system
- (B) Tissue, cell, organ system, organ
- (C) Organ, tissue, cell, organ system
- (D) Cell, organ, tissue, organ system
Show Answer
Answer: A – Cells form tissues, tissues form organs, and organs work together in systems.
Q4. Which structure is found in a plant cell but not in an animal cell?
- (A) Nucleus
- (B) Mitochondrion
- (C) Chloroplast
- (D) Cell membrane
Show Answer
Answer: C – Chloroplasts carry out photosynthesis and are absent from animal cells.
Movement into and out of cells
Q5. Which process moves oxygen from the lungs into the blood?
- (A) Diffusion
- (B) Active transport
- (C) Osmosis
- (D) Transpiration
Show Answer
Answer: A – Oxygen diffuses down its concentration gradient across the alveolar wall.
Q6. A cell is placed in pure water and swells. What explains this?
- (A) Water leaves by active transport
- (B) Solutes diffuse out of the cell
- (C) Water enters by osmosis
- (D) The cell wall dissolves
Show Answer
Answer: C – Water moves by osmosis from a dilute solution into the more concentrated cell sap.
Biological molecules
Q7. Which test gives a brick-red precipitate with a reducing sugar?
- (A) Iodine test
- (B) Biuret test
- (C) Ethanol emulsion test
- (D) Benedict’s test
Show Answer
Answer: D – Benedict’s solution turns brick-red when heated with a reducing sugar.
Q8. Which molecule is a monosaccharide?
- (A) Starch
- (B) Glucose
- (C) Cellulose
- (D) Glycogen
Show Answer
Answer: B – Glucose is a single sugar unit, while starch, cellulose and glycogen are polymers.
Q9. What is the main function of fats in the body?
- (A) Speeding up reactions as enzymes do
- (B) Carrying oxygen
- (C) Energy storage and insulation
- (D) Building cell membranes only
Show Answer
Answer: C – Fats store more energy per gram than carbohydrates and insulate against heat loss.
Enzymes
Q10. Why does a high temperature denature an enzyme?
- (A) It breaks the substrate apart
- (B) It changes the shape of the active site
- (C) It removes water from the cell by evaporation
- (D) It increases the pH sharply
Show Answer
Answer: B – Heat breaks the bonds holding the enzyme shape, so the substrate no longer fits.
Q11. Which statement describes an enzyme?
- (A) A biological catalyst that is not used up in the reaction
- (B) A protein that is broken down during the reaction
- (C) A substrate that speeds up digestion
- (D) A hormone that controls blood sugar
Show Answer
Answer: A – Enzymes lower the activation energy and emerge unchanged from the reaction.
Q12. Amylase works best at pH 7. What happens in very acidic conditions?
- (A) The reaction speeds up steadily
- (B) The substrate becomes an enzyme
- (C) The enzyme is made in larger amounts
- (D) The rate falls because the enzyme denatures
Show Answer
Answer: D – Extreme pH alters the active site shape, reducing the rate of reaction.
Plant nutrition
Q13. Which substances does a plant need for photosynthesis?
- (A) Oxygen and glucose made by the plant
- (B) Nitrogen and water
- (C) Glucose and oxygen
- (D) Carbon dioxide and water
Show Answer
Answer: D – Photosynthesis uses carbon dioxide and water to make glucose and oxygen.
Q14. Where in the leaf does most photosynthesis take place?
- (A) Palisade mesophyll
- (B) Upper epidermis cells without chloroplasts
- (C) Lower epidermis
- (D) Vascular bundle
Show Answer
Answer: A – Palisade cells are packed with chloroplasts near the upper leaf surface.
Q15. Why do plants need magnesium ions?
- (A) To make cell walls strong
- (B) To build DNA in roots
- (C) To make chlorophyll
- (D) To open the stomata
Show Answer
Answer: C – Magnesium is a central part of the chlorophyll molecule.
Human nutrition
Q16. Where is bile produced in the human body?
- (A) Pancreas
- (B) Liver
- (C) Gall bladder
- (D) Stomach
Show Answer
Answer: B – The liver makes bile, which is stored in the gall bladder.
Q17. What is the function of villi in the small intestine?
- (A) To churn food with acid
- (B) To produce digestive enzymes
- (C) To increase the surface area for absorption
- (D) To store digested food
Show Answer
Answer: C – Villi greatly increase surface area, speeding absorption into the blood.
Q18. Which enzyme digests protein in the stomach?
- (A) Amylase
- (B) Pepsin
- (C) Lipase
- (D) Maltase
Show Answer
Answer: B – Pepsin breaks proteins into peptides in acidic stomach conditions.
Transport in plants
Q19. Which tissue transports water from roots to leaves?
- (A) Phloem
- (B) Cambium
- (C) Epidermis
- (D) Xylem
Show Answer
Answer: D – Xylem vessels carry water and dissolved minerals upwards.
Q20. Which tissue in a leaf vein carries sugars away from the leaf?
- (A) Phloem
- (B) Xylem vessels, which carry water and mineral ions upwards from the roots to the leaves
- (C) Cambium
- (D) Epidermis
Show Answer
Answer: A – Phloem in the leaf veins exports sucrose made in photosynthesis to other parts of the plant.
Q21. Which factor increases the rate of transpiration most directly?
- (A) Strong wind
- (B) High humidity
- (C) Low light intensity
- (D) Cool temperature
Show Answer
Answer: A – Wind removes humid air around the leaf, steepening the diffusion gradient.
Transport in animals
Q22. Which blood vessel carries blood away from the heart at high pressure?
- (A) Vein
- (B) Capillary
- (C) Lymph vessel
- (D) Artery
Show Answer
Answer: D – Arteries have thick muscular walls to withstand high pressure.
Q23. What is the function of the bicuspid valve?
- (A) To stop blood entering the lungs
- (B) To prevent backflow from ventricle to atrium
- (C) To pump blood to the body
- (D) To filter blood in the kidney
Show Answer
Answer: B – Valves in the heart ensure blood flows in one direction only.
Q24. Which component of blood carries oxygen?
- (A) Plasma
- (B) Platelets
- (C) Red blood cells
- (D) White blood cells
Show Answer
Answer: C – Red blood cells contain haemoglobin, which binds oxygen.
Diseases and immunity
Q25. Which type of pathogen causes malaria?
- (A) A protoctist (Plasmodium)
- (B) A bacterium
- (C) A virus
- (D) A fungus
Show Answer
Answer: A – Malaria is caused by Plasmodium, a protoctist spread by mosquitoes.
Q26. How does vaccination give long-term protection?
- (A) It kills all pathogens in the blood
- (B) It replaces white blood cells
- (C) It triggers memory cells for a faster second response
- (D) It blocks pathogens from entering the body
Show Answer
Answer: C – Memory cells allow rapid antibody production on later exposure.
Q27. Which defence is a chemical barrier against pathogens?
- (A) Skin
- (B) Stomach acid
- (C) Mucus trapping particles
- (D) Blood clotting
Show Answer
Answer: B – Hydrochloric acid in the stomach kills many ingested pathogens.
Gas exchange in humans
Q28. Which feature of alveoli speeds gas exchange?
- (A) Thick walls with few capillaries
- (B) Dry surfaces with slow blood flow
- (C) A large total volume of air
- (D) Thin walls and a rich blood supply
Show Answer
Answer: D – A short diffusion distance and good blood supply maintain steep gradients.
Q29. What happens to the diaphragm during inhalation?
- (A) It relaxes and domes upwards
- (B) It stops moving completely
- (C) It pushes air out of the lungs
- (D) It contracts and flattens
Show Answer
Answer: D – A flattened diaphragm increases chest volume, lowering lung pressure.
Q30. Which gas is at a higher concentration in exhaled air than in inhaled air?
- (A) Nitrogen from the inhaled air
- (B) Carbon dioxide
- (C) Oxygen
- (D) Argon
Show Answer
Answer: B – Respiration releases carbon dioxide, so exhaled air contains more of it.
Respiration
Q31. Which equation summarises aerobic respiration?
- (A) Glucose + oxygen → carbon dioxide + water + energy
- (B) Glucose → lactic acid + energy
- (C) Glucose + carbon dioxide → oxygen + water
- (D) Glucose + water → oxygen + energy
Show Answer
Answer: A – Aerobic respiration releases energy by oxidising glucose completely.
Q32. Where in the cell does most aerobic respiration take place?
- (A) Nucleus
- (B) Ribosome
- (C) Mitochondrion
- (D) Chloroplast found in plant leaf cells
Show Answer
Answer: C – Mitochondria are the main sites of aerobic respiration.
Q33. What product of anaerobic respiration in muscle causes cramp?
- (A) Ethanol
- (B) Lactic acid
- (C) Carbon dioxide
- (D) Glucose
Show Answer
Answer: B – Anaerobic respiration in muscle produces lactic acid and less energy.
Excretion in humans
Q34. Which organ produces urea?
- (A) Liver
- (B) Kidney
- (C) Bladder
- (D) Lung
Show Answer
Answer: A – The liver deaminates excess amino acids, forming urea.
Q35. In which part of the kidney is blood filtered?
- (A) Loop of Henle deep in the kidney medulla
- (B) Collecting duct
- (C) Glomerulus and Bowman’s capsule
- (D) Ureter
Show Answer
Answer: C – High pressure forces small molecules out of the glomerulus into the capsule.
Q36. Which substance is normally absent from urine?
- (A) Urea
- (B) Water and dissolved salts
- (C) Salts
- (D) Glucose
Show Answer
Answer: D – Glucose is fully reabsorbed in the kidney tubules of a healthy person.
Coordination and response
Q37. Which neurone carries impulses from a receptor to the central nervous system?
- (A) Motor neurone
- (B) Relay neurone
- (C) Sensory neurone
- (D) Effector neurone
Show Answer
Answer: C – Sensory neurones transmit impulses from receptors towards the CNS.
Q38. What is the effector in a reflex arc for the knee-jerk response?
- (A) Spinal cord
- (B) Leg muscle
- (C) Skin receptor
- (D) Brain
Show Answer
Answer: B – The muscle contracts in response to the motor impulse.
Q39. Which hormone lowers blood glucose concentration?
- (A) Adrenaline
- (B) Glucagon
- (C) Oestrogen
- (D) Insulin
Show Answer
Answer: D – Insulin promotes glucose uptake and storage, lowering blood glucose.
Drugs
Q40. Which effect is caused by nicotine in tobacco smoke?
- (A) Narrowing of blood vessels and higher heart rate
- (B) Increased oxygen carried by blood
- (C) Stronger cilia action in airways
- (D) Reduced risk of lung disease
Show Answer
Answer: A – Nicotine is addictive and raises heart rate and blood pressure.
Q41. Why is alcohol harmful to a developing fetus?
- (A) It supplies extra energy to the fetus
- (B) It can damage the developing brain and organs
- (C) It increases oxygen delivery
- (D) It prevents infection of the fetus
Show Answer
Answer: B – Alcohol crosses the placenta and can disrupt normal development.
Q42. What is meant by drug misuse?
- (A) Using a drug in a way that harms health or social life
- (B) Taking a prescribed drug exactly as directed
- (C) Refusing all medicines when ill
- (D) Taking vitamins with food
Show Answer
Answer: A – Misuse means using a drug in a harmful or non-medical way.
Reproduction
Q43. Which process in sexual reproduction halves the chromosome number?
- (A) Fertilisation
- (B) Mitosis
- (C) Meiosis
- (D) Pollination
Show Answer
Answer: C – Meiosis produces haploid gametes from diploid cells.
Q44. In a flower, where are male gametes produced?
- (A) Ovary
- (B) Stigma
- (C) Style
- (D) Anther
Show Answer
Answer: D – Anthers produce pollen grains containing male gametes.
Q45. Which statement is true of asexual reproduction?
- (A) It requires two parents
- (B) It produces genetically varied offspring
- (C) It involves fusion of gametes
- (D) It produces genetically identical offspring
Show Answer
Answer: D – Asexual reproduction uses mitosis, so offspring are clones of the parent.
Inheritance
Q46. What does the term homozygous mean for a particular gene?
- (A) Two different alleles for the gene
- (B) Only one allele for the gene
- (C) Two identical alleles for the gene
- (D) Two alleles for different genes carried on the same chromosome
Show Answer
Answer: C – A homozygous organism carries two copies of the same allele for a gene, one on each homologous chromosome.
Q47. A heterozygous tall plant (Tt) is crossed with a short plant (tt). What proportion of offspring will be short?
- (A) Half
- (B) One quarter
- (C) Three quarters
- (D) All
Show Answer
Answer: A – The cross gives Tt and tt in equal proportions, so half are short.
Q48. Which genotype shows a recessive trait?
- (A) AA
- (B) aa
- (C) Aa
- (D) AB
Show Answer
Answer: B – A recessive trait appears only when both alleles are recessive.
Variation and selection
Q49. Which variation is caused only by the environment?
- (A) Blood group
- (B) Eye colour
- (C) Natural hair colour inherited from parents
- (D) A scar from an injury
Show Answer
Answer: D – A scar results from environmental damage, not from genes.
Q50. What is natural selection?
- (A) Humans choosing animals to breed
- (B) Random change in chromosome number
- (C) Better-adapted organisms surviving and reproducing more
- (D) Migration of species to new areas
Show Answer
Answer: C – Advantageous alleles become more common over generations.
Q51. Which is an example of continuous variation?
- (A) Height in humans
- (B) Blood group in humans
- (C) Ability to roll the tongue
- (D) Flower colour in peas
Show Answer
Answer: A – Height shows a full range of values influenced by genes and environment.
Organisms and their environment
Q52. In a food chain, what is the original source of energy?
- (A) Decomposers
- (B) The Sun
- (C) Herbivores
- (D) Soil minerals
Show Answer
Answer: B – Producers capture light energy, which flows through the food chain.
Q53. Why does a food chain rarely have more than five trophic levels?
- (A) Energy is lost at each transfer
- (B) Top predators eat too little
- (C) Producers run out of sunlight
- (D) Decomposers remove all biomass
Show Answer
Answer: A – Only about 10 percent of energy passes to the next level.
Q54. Which organisms return nutrients to the soil?
- (A) Herbivores that feed on producers
- (B) Carnivores
- (C) Producers
- (D) Decomposers
Show Answer
Answer: D – Decomposers break down dead material, releasing nutrients for plants.
Human influences on ecosystems
Q55. How does deforestation contribute to global warming?
- (A) It increases oxygen production
- (B) It reduces carbon dioxide uptake by trees
- (C) It cools the soil surface
- (D) It increases rainfall locally
Show Answer
Answer: B – Fewer trees mean less photosynthesis removing carbon dioxide.
Q56. What is eutrophication?
- (A) Drying out of a lake in summer
- (B) Freezing of surface water
- (C) Nutrient enrichment causing algal blooms and oxygen loss
- (D) Acid rain damaging forest soil
Show Answer
Answer: C – Excess nitrates cause algae growth; decay then depletes oxygen.
Q57. Which gas is mainly responsible for acid rain from burning fossil fuels?
- (A) Methane
- (B) Sulfur dioxide
- (C) Ozone
- (D) Nitrogen gas in the atmosphere
Show Answer
Answer: B – Sulfur dioxide dissolves in rainwater to form acidic solutions.
Biotechnology and genetic modification
Q58. What is genetic modification?
- (A) Selecting the best plants by eye
- (B) Cross-breeding two varieties
- (C) Changing the genetic material of an organism
- (D) Cloning an organism by cuttings
Show Answer
Answer: C – Genetic modification transfers or alters genes to add a desired trait.
Q59. Why are bacteria used to produce human insulin?
- (A) They grow slowly in fermenters
- (B) They cannot copy human genes
- (C) They need no nutrients to grow
- (D) They reproduce rapidly and can express the human gene
Show Answer
Answer: D – Modified bacteria multiply quickly, producing large amounts of insulin.
Q60. Which is a benefit of genetically modified crops?
- (A) Higher yields or pest resistance
- (B) Greater need for pesticides always
- (C) Reduced genetic diversity in wild species
- (D) Slower growth in all conditions
Show Answer
Answer: A – Modified traits can raise yield and reduce crop losses to pests.
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