IGCSE Biology Practice Test 12 – 60 Questions with Answers (Cambridge 0610)
Work through this test at exam pace, then check each answer and note the syllabus areas where you lost marks.
Characteristics and classification of living organisms
Q1. Which life process involves the removal of waste products of metabolism from the body?
- (A) Nutrition
- (B) Excretion
- (C) Respiration
- (D) Growth
Show Answer
Answer: B – Excretion is the removal of toxic waste products of metabolic reactions, such as urea and carbon dioxide.
Q2. Which feature distinguishes a virus from a bacterium?
- (A) A virus is not made of cells and can only reproduce inside a host cell
- (B) A virus has a nucleus and a cell wall
- (C) A virus can feed by photosynthesis
- (D) A virus is always larger than a bacterium and easily visible under a light microscope
Show Answer
Answer: A – Viruses consist of genetic material in a protein coat and must use a host cell to replicate.
Q3. An animal has a backbone, lays eggs with shells on land, and has dry scaly skin. Which class does it belong to?
- (A) Amphibian
- (B) Fish
- (C) Reptile
- (D) Bird
Show Answer
Answer: C – Reptiles have dry scaly skin and lay shelled eggs on land, unlike amphibians, which need water for reproduction.
Organisation of the organism
Q4. Which organelle controls the activities of the cell and contains the genetic material?
- (A) Vacuole
- (B) Mitochondrion
- (C) Ribosome
- (D) Nucleus
Show Answer
Answer: D – The nucleus holds DNA and directs cell activities such as growth and protein synthesis.
Q5. The stomach, intestines and liver work together as part of which organ system?
- (A) Circulatory system
- (B) Nervous system
- (C) Respiratory system
- (D) Digestive system
Show Answer
Answer: D – These organs cooperate to break down food and absorb nutrients, which is the role of the digestive system.
Q6. What is the function of the large central vacuole in a mature plant cell?
- (A) To carry out photosynthesis
- (B) To store cell sap and keep the cell firm
- (C) To produce energy by respiration
- (D) To join amino acids into proteins during protein synthesis
Show Answer
Answer: B – The vacuole, filled with cell sap, pushes the cytoplasm against the cell wall and maintains turgor.
Movement into and out of cells
Q7. A plant cell placed in a concentrated salt solution becomes plasmolysed. What has happened?
- (A) Water has entered the cell by osmosis and the cell has burst
- (B) Water has left the cell by osmosis and the cytoplasm has pulled away from the wall
- (C) Salt has entered the cell by active transport
- (D) The cell wall has dissolved in the salt solution
Show Answer
Answer: B – Water leaves the cell by osmosis into the stronger solution, so the vacuole shrinks and the cytoplasm pulls away from the cell wall.
Q8. Which statement correctly describes diffusion?
- (A) The movement of water through a partially permeable membrane
- (B) The movement of ions against a concentration gradient using energy
- (C) The net movement of particles from a higher to a lower concentration
- (D) The movement of large proteins through the cell wall
Show Answer
Answer: C – Diffusion is the passive, net movement of particles down a concentration gradient.
Q9. Root hair cells absorb mineral ions from very dilute soil water. Which process allows this, and why is it needed?
- (A) Active transport, because ions must be taken up against a concentration gradient
- (B) Osmosis, because ions dissolve in water
- (C) Diffusion, because ions move freely through the membrane
- (D) Transpiration, because water pulls ions upwards
Show Answer
Answer: A – The ion concentration inside the root hair cell is higher than in the soil, so energy is needed to move ions inwards.
Biological molecules
Q10. A food sample gives a purple colour with biuret solution. Which nutrient is present?
- (A) Reducing sugar
- (B) Starch
- (C) Protein
- (D) Vitamin C
Show Answer
Answer: C – Biuret solution turns from blue to purple when protein is present.
Q11. Which carbohydrate is the main storage compound in animal cells?
- (A) Cellulose
- (B) Maltose
- (C) Starch
- (D) Glycogen
Show Answer
Answer: D – Animals store carbohydrate as glycogen, mainly in the liver and muscles, while plants store it as starch.
Q12. Which statement describes how an enzyme works?
- (A) The substrate fits into the active site, the reaction happens, and the enzyme is unchanged
- (B) The enzyme is broken down into products at the end of the reaction
- (C) The enzyme changes the products into a different substrate
- (D) The enzyme binds permanently to the substrate
Show Answer
Answer: A – Enzymes are biological catalysts: they speed up a reaction without being used up or changed by it.
Enzymes
Q13. An enzyme solution is boiled, cooled, and then mixed with its substrate. No reaction occurs. What is the best explanation?
- (A) The substrate was destroyed by boiling
- (B) Boiling denatured the enzyme, changing its active site
- (C) Cooling the enzyme stopped all molecular movement
- (D) The enzyme needs light to work
Show Answer
Answer: B – Boiling breaks bonds in the enzyme, so its shape and active site are lost and the substrate can no longer fit.
Q14. Pepsin works best in strongly acidic conditions in the stomach. What does this show about pepsin?
- (A) Its optimum pH is low
- (B) It is destroyed by acid
- (C) It works only in the mouth
- (D) It digests fats, not proteins
Show Answer
Answer: A – Each enzyme has an optimum pH; for pepsin this is around pH 2, matching stomach acid.
Q15. Why does the rate of an enzyme reaction increase when the substrate concentration is raised, up to a point?
- (A) The enzyme molecules become larger
- (B) The temperature of the mixture rises during the reaction
- (C) More active sites become occupied more often
- (D) The pH of the mixture changes
Show Answer
Answer: C – More substrate molecules mean more frequent collisions with active sites, until all sites are saturated.
Plant nutrition
Q16. Which mineral ion is needed to make chlorophyll, so a deficiency causes yellow leaves?
- (A) Calcium
- (B) Phosphate
- (C) Potassium
- (D) Magnesium
Show Answer
Answer: D – Magnesium is a component of the chlorophyll molecule, so plants lacking it cannot make enough chlorophyll.
Q17. A leaf is tested for starch after being kept in darkness for two days. The test is negative. What does this show?
- (A) The leaf cannot make starch at all
- (B) The leaf has no chloroplasts
- (C) The leaf respired but made no new starch
- (D) Starch in the leaf was used up because photosynthesis could not occur
Show Answer
Answer: D – In darkness there is no photosynthesis, so stored starch is used in respiration and is not replaced.
Q18. Which part of a leaf contains most of the chloroplasts for photosynthesis?
- (A) The upper epidermis, a transparent protective layer
- (B) The palisade mesophyll
- (C) The xylem vessels
- (D) The lower epidermis
Show Answer
Answer: B – Palisade cells are packed with chloroplasts and sit near the upper surface, where light is strongest.
Human nutrition
Q19. Where does chemical digestion of protein begin in humans?
- (A) In the stomach, by pepsin
- (B) In the mouth, by amylase
- (C) In the small intestine, by lipase
- (D) In the large intestine, by bacteria
Show Answer
Answer: A – Pepsin in gastric juice begins breaking proteins into smaller peptides in the acidic stomach.
Q20. A person eats a meal rich in starch. Which sequence shows the main stages of its digestion and absorption?
- (A) Stomach acid breaks starch, then it is absorbed in the colon
- (B) Lipase breaks starch in the ileum, then it enters the blood
- (C) Amylase breaks starch to maltose, maltase to glucose, then glucose is absorbed in the ileum
- (D) Bile breaks starch to glucose, then it is absorbed in the stomach
Show Answer
Answer: C – Amylase digests starch to maltose, maltase completes the breakdown to glucose, and glucose is absorbed through the ileum wall.
Q21. Which vitamin is needed for the absorption of calcium and for healthy teeth and bones?
- (A) Vitamin D
- (B) Vitamin A
- (C) Vitamin C
- (D) Vitamin B
Show Answer
Answer: A – Vitamin D, made in the skin in sunlight, promotes calcium uptake and bone mineralisation.
Transport in plants
Q22. Which cells in a leaf control the opening and closing of stomata?
- (A) Palisade cells
- (B) Epidermal cells
- (C) Guard cells
- (D) Phloem cells
Show Answer
Answer: C – Guard cells change shape as they gain or lose water, opening or closing the stomatal pore between them.
Q23. Sucrose made in a leaf is carried to a growing root. Which tissue carries it, and in which direction?
- (A) Xylem, upwards only
- (B) Xylem, in both directions through the plant
- (C) Phloem, upwards only
- (D) Phloem, from source to sink
Show Answer
Answer: D – Phloem translocates sugars from sources, such as leaves, to sinks, such as roots and growing regions.
Q24. A plant is placed in humid air with still conditions. What happens to transpiration and why?
- (A) It increases, because humidity opens stomata wider
- (B) It decreases, because the water vapour gradient is smaller
- (C) It stops, because the roots stop absorbing water
- (D) It increases, because still air holds more water
Show Answer
Answer: B – Humid, still air around the leaf reduces the concentration gradient for water vapour, slowing diffusion out.
Transport in animals
Q25. Which chamber of the heart receives deoxygenated blood from the body?
- (A) Left atrium
- (B) Right atrium
- (C) Left ventricle
- (D) Right ventricle
Show Answer
Answer: B – The vena cava returns deoxygenated blood from the body into the right atrium.
Q26. What is the role of valves in veins?
- (A) To prevent the backflow of blood
- (B) To pump blood towards the heart by contraction
- (C) To allow exchange with tissues
- (D) To carry oxygenated blood only
Show Answer
Answer: A – Veins carry blood at low pressure, so valves stop it flowing backwards between heartbeats.
Q27. Tissue fluid is formed when plasma leaks from capillaries. How is most of it returned to the blood?
- (A) It drains into the arteries directly from the tissues
- (B) It evaporates from the skin
- (C) It re-enters capillaries and lymph vessels
- (D) It is excreted by the kidneys at once
Show Answer
Answer: C – Most tissue fluid passes back into the capillaries, and the remainder drains into lymph vessels.
Diseases and immunity
Q28. Which statement describes active immunity?
- (A) Antibodies are injected directly into the blood
- (B) A baby receives antibodies in breast milk
- (C) Antibodies are borrowed from another person
- (D) The body makes its own antibodies and memory cells
Show Answer
Answer: D – In active immunity the immune system responds itself, producing antibodies and long-lasting memory cells.
Q29. Cholera bacteria are spread mainly by which route?
- (A) Droplets in coughs and sneezes
- (B) Bites from infected insects
- (C) Direct contact with skin
- (D) Water contaminated with faeces
Show Answer
Answer: D – Cholera spreads when drinking water is contaminated with faeces containing the bacteria, so clean water and sanitation prevent it.
Q30. A white blood cell engulfs a bacterium and digests it. What is this process called?
- (A) Vaccination
- (B) Phagocytosis
- (C) Agglutination
- (D) Fermentation
Show Answer
Answer: B – Phagocytes engulf pathogens, enclose them in a vacuole, and digest them with enzymes.
Gas exchange in humans
Q31. Which structure prevents food from entering the windpipe when swallowing?
- (A) The epiglottis
- (B) The diaphragm
- (C) The alveolus
- (D) The bronchiole
Show Answer
Answer: A – The epiglottis is a flap that closes over the trachea during swallowing, directing food into the oesophagus.
Q32. In the lungs, carbon dioxide diffuses from the blood into the alveoli because of which gradient?
- (A) Oxygen is higher in the blood than in the alveoli
- (B) Carbon dioxide is equal on both sides
- (C) Carbon dioxide is higher in the blood than in the alveolar air
- (D) Nitrogen is higher in the alveolar air
Show Answer
Answer: C – Gas exchange follows concentration gradients, so carbon dioxide moves from blood, where it is concentrated, into the alveoli.
Q33. Why do the walls of the trachea contain rings of cartilage?
- (A) To keep the airway open during breathing movements
- (B) To absorb oxygen into the blood
- (C) To produce mucus for trapping dust
- (D) To contract and push air into the lungs
Show Answer
Answer: A – The C-shaped cartilage rings support the trachea and stop it collapsing when air pressure changes.
Respiration
Q34. Which substance is produced by anaerobic respiration in yeast but not in human muscle?
- (A) Lactic acid
- (B) Water
- (C) Ethanol
- (D) Carbon dioxide only
Show Answer
Answer: C – Yeast carries out alcoholic fermentation, producing ethanol and carbon dioxide, while muscle produces lactic acid.
Q35. During heavy exercise, breathing rate and heart rate both rise. What is the main reason?
- (A) To remove excess glucose from the blood
- (B) To cool the muscles by sweating
- (C) To reduce the amount of oxygen used
- (D) To supply more oxygen and remove carbon dioxide faster
Show Answer
Answer: D – Muscles respiring faster need more oxygen and produce more carbon dioxide, so delivery and removal must both increase.
Q36. Which organelle is the site of aerobic respiration?
- (A) Chloroplast, the site of photosynthesis
- (B) Mitochondrion
- (C) Nucleus
- (D) Ribosome
Show Answer
Answer: B – Aerobic respiration takes place in the mitochondria, releasing energy from glucose using oxygen.
Excretion in humans
Q37. Which of these is an excretory product removed by the lungs?
- (A) Urea
- (B) Carbon dioxide
- (C) Excess salts
- (D) Bile pigments, which colour the faeces
Show Answer
Answer: B – Carbon dioxide, a waste product of respiration, diffuses from blood into the alveoli and is breathed out.
Q38. In the kidney tubule, which substance is normally reabsorbed completely so that none appears in urine?
- (A) Glucose
- (B) Urea
- (C) Excess water
- (D) Sodium ions
Show Answer
Answer: A – In a healthy person all filtered glucose is reabsorbed in the first part of the tubule, so urine contains no glucose.
Coordination and response
Q39. Which sequence correctly shows the pathway of a simple spinal reflex?
- (A) Effector, motor neurone, spinal cord, sensory neurone, receptor
- (B) Receptor, motor neurone, spinal cord, sensory neurone, effector
- (C) Receptor, sensory neurone, spinal cord, motor neurone, effector
- (D) Sensory neurone, receptor, motor neurone, spinal cord, effector
Show Answer
Answer: C – The impulse travels from receptor to sensory neurone, through the spinal cord, then out along a motor neurone to the effector.
Q40. Adrenaline is released in a stressful situation. Which effect does it have?
- (A) It lowers blood glucose and slows the heart
- (B) It constricts the pupils and slows breathing
- (C) It reduces blood flow to the muscles
- (D) It increases heart rate and blood glucose concentration
Show Answer
Answer: D – Adrenaline prepares the body for action by raising heart rate, breathing rate and blood glucose.
Drugs
Q41. Nicotine in tobacco smoke affects the body in which way?
- (A) It coats the lungs with tar
- (B) It reduces oxygen by binding haemoglobin
- (C) It paralyses the cilia in the airways
- (D) It is addictive and raises heart rate and blood pressure
Show Answer
Answer: D – Nicotine is the addictive drug in tobacco and it stimulates the heart, increasing rate and pressure.
Q42. Why should antibiotics not be taken for a common cold?
- (A) The cold virus is killed by rest alone
- (B) Colds are caused by viruses, which antibiotics cannot kill
- (C) Antibiotics weaken the immune system permanently
- (D) Colds are caused by fungi, not bacteria
Show Answer
Answer: B – Antibiotics act on bacteria, not viruses, so they do not cure a viral cold and overuse encourages resistance.
Reproduction
Q43. Which part of a flower receives pollen during pollination?
- (A) The stigma
- (B) The ovule
- (C) The filament
- (D) The style
Show Answer
Answer: A – Pollen lands on the sticky stigma, then a pollen tube grows down the style to the ovule.
Q44. What is the main advantage of sexual reproduction over asexual reproduction?
- (A) Offspring are produced more quickly
- (B) No partner is needed
- (C) Offspring show variation, helping adaptation to changing conditions
- (D) All offspring are genetically identical to the parent
Show Answer
Answer: C – Mixing genes from two parents creates varied offspring, some of which may be better suited if conditions change.
Q45. After fertilisation in a flowering plant, what does the ovule become?
- (A) A seed
- (B) A fruit
- (C) A pollen grain
- (D) An anther
Show Answer
Answer: A – The fertilised ovule develops into a seed, while the ovary wall becomes the fruit.
Inheritance
Q46. What is the genotype of an organism that is heterozygous for a trait controlled by alleles R and r?
- (A) RR
- (B) rr
- (C) Rr
- (D) R only
Show Answer
Answer: C – Heterozygous means the two alleles are different, so the genotype is written Rr.
Q47. A man with blood group B marries a woman with blood group O. Their child has blood group O. What must the man’s genotype be?
- (A) BB only
- (B) AB
- (C) OO
- (D) BO
Show Answer
Answer: D – The child must receive an O allele from each parent, so the father, who shows group B, must carry a hidden O allele.
Q48. Which process produces genetically different gametes by halving the chromosome number?
- (A) Mitosis
- (B) Meiosis
- (C) Fertilisation
- (D) Binary fission
Show Answer
Answer: B – Meiosis produces haploid gametes with new gene combinations, while mitosis produces identical diploid cells.
Variation and selection
Q49. A plant grown in shade develops larger leaves than the same species grown in bright light. This is an example of which kind of variation?
- (A) Genetic variation only
- (B) Environmental variation
- (C) Discontinuous variation
- (D) Mutation
Show Answer
Answer: B – The difference is caused by the growing conditions, not by a difference in genes, so it is environmental variation.
Q50. Which of these is an example of discontinuous variation in humans?
- (A) Blood group
- (B) Height
- (C) Body mass
- (D) Skin colour shade
Show Answer
Answer: A – Blood group falls into distinct categories with no intermediates, unlike height or body mass, which vary continuously.
Q51. Pesticide resistance in insects is an example of which process?
- (A) Artificial selection by farmers
- (B) Genetic engineering
- (C) Natural selection
- (D) Asexual reproduction
Show Answer
Answer: C – Insects with resistance genes survive spraying, reproduce, and pass the genes on, so the resistant type becomes common.
Organisms and their environment
Q52. Which organism is a decomposer in a woodland food web?
- (A) An oak tree, a large producer in the woodland
- (B) A rabbit
- (C) A fox
- (D) A fungus breaking down dead leaves
Show Answer
Answer: D – Decomposers feed on dead material and waste, returning mineral ions to the soil for producers to use again.
Q53. In a pyramid of biomass, why is the producer level usually the largest?
- (A) Producers reproduce fastest
- (B) Producers are the largest organisms
- (C) Consumers eat only producers
- (D) Energy is lost at each level, so less biomass can be supported above
Show Answer
Answer: D – Because much energy is lost in respiration and waste, each higher level can support less living material.
Q54. Which factor is a biotic factor in a pond habitat?
- (A) Water temperature, an abiotic factor in the pond
- (B) The number of predators present
- (C) Light intensity
- (D) pH of the water
Show Answer
Answer: B – Biotic factors arise from living organisms, such as predators, competitors and food availability, unlike abiotic factors such as temperature.
Human influences on ecosystems
Q55. Which farming practice can cause eutrophication in a nearby lake?
- (A) Excess fertiliser washing into the water
- (B) Crop rotation with legumes, which improves soil nitrogen
- (C) Leaving field margins uncut
- (D) Using drip irrigation
Show Answer
Answer: A – Nitrates and phosphates from fertiliser feed algal blooms, which block light and, when they decay, deplete oxygen.
Q56. Which of these is a non-renewable resource whose use contributes to climate change?
- (A) Wind energy
- (B) Solar energy
- (C) Coal
- (D) Tidal energy
Show Answer
Answer: C – Coal is a fossil fuel; burning it releases stored carbon as carbon dioxide, strengthening the greenhouse effect.
Q57. Why is conserving a gene pool important for an endangered species?
- (A) A larger gene pool gives more variation for adaptation and survival
- (B) A larger gene pool makes all individuals identical
- (C) A larger gene pool stops all mutations
- (D) A larger gene pool prevents any breeding
Show Answer
Answer: A – Genetic diversity increases the chance that some individuals can cope with disease or environmental change.
Biotechnology and genetic modification
Q58. In a fermenter used to grow yeast for bread making, which condition must be controlled?
- (A) The colour of the vessel
- (B) The shape of the yeast cells
- (C) Temperature, pH and nutrient supply
- (D) The amount of sunlight on the vessel
Show Answer
Answer: C – Microorganisms in a fermenter need steady temperature, pH and nutrients for rapid, controlled growth.
Q59. A crop is genetically modified to resist a herbicide. What is a possible benefit to farmers?
- (A) The crop needs no water at all
- (B) The crop grows in complete darkness without any light
- (C) The crop produces its own fertiliser
- (D) Weeds can be killed without harming the crop
Show Answer
Answer: D – Herbicide resistance lets farmers spray weeds while the crop survives, reducing competition for light and nutrients.
Q60. Which step is part of producing a genetically modified bacterium that makes insulin?
- (A) Heating the bacteria until they die
- (B) Inserting the human insulin gene into a plasmid, then into the bacterium
- (C) Removing all DNA from the bacterium
- (D) Feeding the bacteria insulin tablets
Show Answer
Answer: B – The insulin gene is cut out, placed in a plasmid vector, and introduced into bacteria, which then express the gene.
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