GCSE Biology Practice Test 16 – 60 Questions with Answers (AQA 8461)

Work through all 60 questions steadily, checking each answer before moving on to the next section.

Cell biology

Q1. A student measures a cell image as 24 mm long. The real cell is 0.2 mm long. What is the magnification of the image?

  • (A) x120
  • (B) x12
  • (C) x48
  • (D) x480
Show Answer

Answer: A – Magnification = image size divided by real size: 24 / 0.2 = 120.

Q2. Which structure is found in a plant cell but is absent from most animal cells?

  • (A) A nucleus
  • (B) A permanent vacuole filled with cell sap
  • (C) A cell membrane
  • (D) Mitochondria
Show Answer

Answer: B – Plant cells have a large permanent vacuole, a cell wall and chloroplasts; animal cells do not.

Q3. The main function of mitochondria is to release energy by which process?

  • (A) Photosynthesis
  • (B) Protein synthesis
  • (C) Aerobic respiration
  • (D) Cell division
Show Answer

Answer: C – Mitochondria are the site of aerobic respiration, which releases energy from glucose.

Q4. Proteins are made on which small structures in the cytoplasm?

  • (A) Vacuoles
  • (B) Chloroplasts
  • (C) Cell walls
  • (D) Ribosomes
Show Answer

Answer: D – Ribosomes are the site of protein synthesis in both plant and animal cells.

Q5. Why do small cells exchange substances by diffusion more efficiently than large cells?

  • (A) Because they have a larger surface area compared with their volume
  • (B) Because they have thicker cell walls
  • (C) Because they contain more mitochondria
  • (D) Because they divide faster
Show Answer

Answer: A – A large surface area to volume ratio gives more surface for diffusion relative to the cell’s needs.

Q6. A cell is observed to contain many chloroplasts. Which process is it most likely to carry out rapidly?

  • (A) Respiration only
  • (B) Photosynthesis
  • (C) Active transport of mineral ions
  • (D) Protein digestion
Show Answer

Answer: B – Chloroplasts contain chlorophyll and are the site of photosynthesis.

Q7. In a bacterial cell, where is most of the genetic material found?

  • (A) Inside a nucleus
  • (B) Inside mitochondria
  • (C) Free in the cytoplasm in a single circular chromosome
  • (D) On plasmids only
Show Answer

Answer: C – Bacterial cells have no nucleus; their main chromosome floats in the cytoplasm.

Q8. What is the function of the cell wall in a plant cell?

  • (A) To control substances entering the cell
  • (B) To release energy
  • (C) To make proteins
  • (D) To strengthen and support the cell
Show Answer

Answer: D – The cellulose cell wall strengthens and supports plant cells.

Organisation

Q9. Amylase is produced in the salivary glands and the pancreas. What does it break down?

  • (A) Starch into sugars
  • (B) Proteins into amino acids
  • (C) Fats into fatty acids and glycerol
  • (D) Cellulose into glucose
Show Answer

Answer: A – Amylase catalyses the breakdown of starch to sugars.

Q10. Protease enzymes break down proteins into which smaller molecules?

  • (A) Fatty acids
  • (B) Amino acids
  • (C) Simple sugars
  • (D) Glycerol
Show Answer

Answer: B – Proteases hydrolyse proteins into amino acids.

Q11. Lipase breaks down lipids into fatty acids and which other product?

  • (A) Amino acids
  • (B) Glucose
  • (C) Glycerol
  • (D) Starch
Show Answer

Answer: C – Lipase produces fatty acids and glycerol from lipids.

Q12. Bile is produced in the liver and stored in the gall bladder. What is its main role in digestion?

  • (A) It breaks down starch
  • (B) It produces protease
  • (C) It absorbs amino acids
  • (D) It neutralises stomach acid and emulsifies fats
Show Answer

Answer: D – Bile is alkaline, neutralises acid, and emulsifies fats into small droplets.

Q13. Why does emulsification of fats speed up digestion?

  • (A) It increases the surface area for lipase to act on
  • (B) It kills bacteria
  • (C) It lowers the pH
  • (D) It turns fats into sugars
Show Answer

Answer: A – Smaller fat droplets give lipase a larger surface area to work on.

Q14. Where in the digestive system are most nutrients absorbed into the blood?

  • (A) The stomach
  • (B) The small intestine
  • (C) The large intestine
  • (D) The oesophagus
Show Answer

Answer: B – The small intestine has villi adapted for absorption of digested food.

Q15. Which adaptation of villi increases absorption?

  • (A) A thick wall
  • (B) A dry surface
  • (C) A large surface area and a rich blood supply
  • (D) A lack of capillaries
Show Answer

Answer: C – Villi have a large surface area, thin walls and many capillaries for rapid absorption.

Q16. The stomach produces hydrochloric acid. What is its function?

  • (A) To digest starch
  • (B) To emulsify fats
  • (C) To absorb water
  • (D) To kill bacteria and provide the optimum pH for protease
Show Answer

Answer: D – Stomach acid kills pathogens and gives pepsin its acidic optimum pH.

Q17. Enzymes work best at an optimum temperature and pH. What happens to an enzyme at a very high temperature?

  • (A) It denatures and its active site changes shape
  • (B) It works faster forever
  • (C) It becomes a different enzyme
  • (D) It is digested by acid
Show Answer

Answer: A – High temperature breaks bonds in the enzyme, changing the active site shape so it no longer fits the substrate.

Infection and response

Q18. Which of these is a pathogen?

  • (A) A white blood cell
  • (B) A bacterium that causes disease
  • (C) An antibody
  • (D) A red blood cell
Show Answer

Answer: B – Pathogens are microorganisms that cause disease, including bacteria, viruses, fungi and protists.

Q19. Bacteria can cause disease by producing toxins and by doing what?

  • (A) Producing antibodies
  • (B) Carrying oxygen
  • (C) Damaging host cells as they reproduce
  • (D) Blocking nerve impulses only
Show Answer

Answer: C – Bacteria damage cells and release toxins that make a person ill.

Q20. Viruses reproduce by taking over host cells. What do they do inside a host cell?

  • (A) They divide by binary fission
  • (B) They photosynthesise
  • (C) They produce antibiotics
  • (D) They use the cell machinery to make many new viruses
Show Answer

Answer: D – Viruses invade living cells and hijack them to produce copies of themselves.

Q21. Which of these illnesses is caused by a virus rather than another type of pathogen?

  • (A) Measles
  • (B) Salmonella food poisoning
  • (C) Athlete’s foot
  • (D) Malaria
Show Answer

Answer: A – Measles is a viral disease; salmonella is bacterial, athlete’s foot is fungal and malaria is caused by a protist.

Q22. Malaria is caused by a protist and spread by which vector?

  • (A) Fleas
  • (B) Mosquitoes
  • (C) Contaminated water only
  • (D) Direct coughing
Show Answer

Answer: B – Female Anopheles mosquitoes transmit the malaria protist when they bite.

Q23. Which is a fungal disease in humans?

  • (A) Tuberculosis
  • (B) HIV
  • (C) Athlete’s foot
  • (D) Cholera
Show Answer

Answer: C – Athlete’s foot is caused by a fungus growing on skin.

Q24. Which of these is a defence that stops pathogens entering the body?

  • (A) Antibodies in the blood
  • (B) Memory cells
  • (C) Fever
  • (D) Skin acting as a barrier
Show Answer

Answer: D – Skin is a physical barrier; antibodies and memory cells act after entry.

Q25. Mucus in the nose and trachea traps pathogens. What then removes the mucus?

  • (A) Cilia sweeping it towards the throat
  • (B) Stomach acid only
  • (C) Sweat glands
  • (D) Red blood cells
Show Answer

Answer: A – Cilia move mucus up and away from the lungs.

Q26. How does hydrochloric acid in the stomach act as a non-specific defence?

  • (A) It produces white blood cells
  • (B) It kills many pathogens swallowed with food
  • (C) It makes antibodies
  • (D) It raises body temperature
Show Answer

Answer: B – Hydrochloric acid in the stomach destroys many ingested pathogens.

Bioenergetics

Q27. Give the word equation for photosynthesis.

  • (A) Glucose + oxygen -> carbon dioxide + water
  • (B) Carbon dioxide + oxygen -> glucose + water
  • (C) Carbon dioxide + water -> glucose + oxygen
  • (D) Glucose + water -> carbon dioxide + oxygen
Show Answer

Answer: C – Photosynthesis uses carbon dioxide and water to make glucose and releases oxygen.

Q28. Which organelle in a plant cell is the site of photosynthesis?

  • (A) The mitochondrion
  • (B) The nucleus
  • (C) The vacuole
  • (D) The chloroplast
Show Answer

Answer: D – Chloroplasts contain chlorophyll and carry out photosynthesis.

Q29. Chlorophyll is a pigment that absorbs which colours of light most strongly?

  • (A) Red and blue light
  • (B) Green light
  • (C) Yellow light only
  • (D) Infrared light only
Show Answer

Answer: A – Chlorophyll absorbs red and blue light well and reflects green light, which is why leaves look green.

Q30. A plant in bright light at a warm temperature photosynthesises slowly because carbon dioxide is very low. Which factor is limiting the rate?

  • (A) Light intensity
  • (B) Carbon dioxide concentration
  • (C) Oxygen concentration
  • (D) Soil pH
Show Answer

Answer: B – When light and temperature are sufficient, a shortage of carbon dioxide limits photosynthesis.


Q31. At low light intensity, increasing light intensity increases the rate of photosynthesis. What is limiting the rate in this case?

  • (A) Temperature
  • (B) Chlorophyll amount only
  • (C) Light intensity
  • (D) Water in the soil only
Show Answer

Answer: C – When light is scarce, light is the limiting factor.

Q32. A plant is kept in bright light with plenty of carbon dioxide, but photosynthesis does not increase when temperature rises further. What is most likely limiting it now?

  • (A) Light intensity only
  • (B) The colour of the pot
  • (C) The time of day only
  • (D) Another factor such as carbon dioxide concentration
Show Answer

Answer: D – Once one factor is sufficient, another factor becomes limiting.

Q33. Give the word equation for aerobic respiration.

  • (A) Glucose + oxygen -> carbon dioxide + water + energy
  • (B) Glucose -> lactic acid + energy
  • (C) Carbon dioxide + water -> glucose + oxygen
  • (D) Glucose + oxygen -> lactic acid + water
Show Answer

Answer: A – Aerobic respiration breaks down glucose with oxygen, releasing energy, carbon dioxide and water.

Q34. Which process releases the most energy from each glucose molecule?

  • (A) Anaerobic respiration in muscle
  • (B) Aerobic respiration
  • (C) Anaerobic respiration in yeast
  • (D) Photosynthesis
Show Answer

Answer: B – Aerobic respiration releases far more energy per glucose molecule than anaerobic respiration.

Q35. Give the word equation for anaerobic respiration in a muscle cell.

  • (A) Glucose + oxygen -> carbon dioxide + water
  • (B) Glucose -> ethanol + carbon dioxide
  • (C) Glucose -> lactic acid + energy
  • (D) Glucose -> oxygen + energy
Show Answer

Answer: C – Muscle cells without enough oxygen break glucose down to lactic acid, releasing less energy.

Homeostasis and response

Q36. A reflex action is rapid and automatic. Which feature of a reflex arc makes it fast?

  • (A) It uses hormones
  • (B) It travels through the blood
  • (C) It involves memory cells
  • (D) The impulse does not need to be processed by the conscious brain
Show Answer

Answer: D – Reflexes bypass conscious thought, so the response is quicker.

Q37. In a reflex arc, which is the correct order of structures?

  • (A) Receptor, sensory neurone, relay neurone, motor neurone, effector
  • (B) Effector, motor neurone, relay neurone, sensory neurone, receptor
  • (C) Receptor, motor neurone, sensory neurone, effector, relay neurone
  • (D) Sensory neurone, receptor, motor neurone, effector, relay neurone
Show Answer

Answer: A – Impulses pass from receptor to sensory neurone, relay neurone, motor neurone and effector.

Q38. What is an effector in a reflex arc?

  • (A) A sense organ
  • (B) A muscle or gland that carries out the response
  • (C) A relay neurone in the brain
  • (D) A hormone gland only
Show Answer

Answer: B – Effectors are muscles that contract or glands that secrete in response to a stimulus.

Q39. Which part of the nervous system coordinates reflex actions?

  • (A) The sensory neurones only
  • (B) The effectors only
  • (C) The central nervous system, including the spinal cord
  • (D) The blood system
Show Answer

Answer: C – The CNS, often the spinal cord, coordinates reflexes.

Q40. The brain, spinal cord and neurones are all part of which system?

  • (A) The endocrine system
  • (B) The circulatory system
  • (C) The digestive system
  • (D) The nervous system
Show Answer

Answer: D – The nervous system includes the brain, spinal cord and neurones.

Q41. Neurones carry electrical impulses. What is a synapse?

  • (A) A gap between two neurones where chemicals transmit the impulse
  • (B) A type of muscle
  • (C) A hormone gland
  • (D) A part of the eye
Show Answer

Answer: A – At a synapse, chemicals diffuse across the gap to pass the impulse to the next neurone.

Q42. Why do impulses travel in only one direction across a synapse?

  • (A) Because neurones are too long
  • (B) Because transmitter chemicals are released on one side only and receptors are on the other side
  • (C) Because blood flows one way
  • (D) Because muscles pull one way
Show Answer

Answer: B – Chemical release on the presynaptic side and receptors on the postsynaptic side enforce one-way transmission.

Q43. Which hormone is produced by the pancreas to lower blood glucose?

  • (A) Glucagon
  • (B) Adrenaline
  • (C) Insulin
  • (D) Thyroxine
Show Answer

Answer: C – Insulin lowers blood glucose by promoting uptake and conversion to glycogen.

Q44. When blood glucose rises after a meal, what does insulin cause liver and muscle cells to do?

  • (A) Release glucagon
  • (B) Break down glycogen
  • (C) Stop respiring
  • (D) Convert glucose to glycogen for storage
Show Answer

Answer: D – Insulin stimulates glycogen formation, reducing blood glucose.

Inheritance, variation and evolution

Q45. DNA is found in the nucleus of a cell. What is its main function?

  • (A) To store genetic information that controls protein production
  • (B) To release energy
  • (C) To transport oxygen
  • (D) To digest food
Show Answer

Answer: A – DNA carries instructions for making proteins, which determine cell functions.

Q46. A gene is a section of DNA that codes for which type of molecule?

  • (A) A fat
  • (B) A protein
  • (C) A carbohydrate only
  • (D) A vitamin
Show Answer

Answer: B – Genes code for specific proteins, including enzymes.

Q47. DNA has a double helix structure. Which bases pair together?

  • (A) A with C, and T with G
  • (B) A with G, and C with T
  • (C) A with T, and C with G
  • (D) All bases pair randomly
Show Answer

Answer: C – Complementary base pairing is A-T and C-G.

Q48. Chromosomes are made of DNA and protein. Where are chromosomes found in a human body cell?

  • (A) In the cytoplasm singly
  • (B) In mitochondria only
  • (C) In the cell membrane
  • (D) In the nucleus, in pairs
Show Answer

Answer: D – Human body cells contain 23 pairs of chromosomes in the nucleus.

Q49. Meiosis produces gametes. How many chromosomes does a human gamete contain compared with a body cell?

  • (A) Half as many: 23 instead of 46
  • (B) The same number: 46
  • (C) Twice as many: 92
  • (D) One quarter: 12
Show Answer

Answer: A – Meiosis halves the chromosome number so fertilisation restores 46.

Q50. During meiosis, chromosome pairs separate and new combinations form. What is the result?

  • (A) Genetically identical diploid cells
  • (B) Genetically different haploid cells
  • (C) Four identical body cells
  • (D) Two diploid cells
Show Answer

Answer: B – Meiosis produces genetically varied haploid gametes.

Q51. Sexual reproduction leads to variation. Which process contributes most to this variation?

  • (A) Mitosis alone
  • (B) Binary fission
  • (C) Random combination of gametes and crossing over in meiosis
  • (D) Cloning
Show Answer

Answer: C – Meiosis and random fertilisation create new gene combinations.

Q52. Asexual reproduction produces offspring that are genetically identical to the parent. What is the main disadvantage?

  • (A) It is very slow
  • (B) It needs two parents
  • (C) It produces gametes
  • (D) The population has little variation to cope with environmental change
Show Answer

Answer: D – Clones lack variation, so a new disease or change may affect them all.

Ecology

Q53. In a food chain, grass is eaten by a rabbit, which is eaten by a fox. What is the rabbit in this chain?

  • (A) A primary consumer
  • (B) A producer
  • (C) A secondary consumer
  • (D) A decomposer
Show Answer

Answer: A – Primary consumers eat producers; the fox is the secondary consumer.

Q54. Producers in a food chain are organisms that make their own food. Which organism is a producer?

  • (A) A rabbit
  • (B) A green plant
  • (C) A fungus
  • (D) A fox
Show Answer

Answer: B – Green plants photosynthesise and form the base of most food chains.

Q55. A food web is more realistic than a single food chain. Why?

  • (A) Because food webs have no producers
  • (B) Because food chains are always longer
  • (C) Because most organisms eat more than one type of food
  • (D) Because decomposers are absent
Show Answer

Answer: C – Food webs show the many feeding relationships in a habitat.

Q56. Decomposers break down dead organisms. Which organisms are decomposers?

  • (A) Green plants
  • (B) Herbivores
  • (C) Carnivores
  • (D) Bacteria and fungi
Show Answer

Answer: D – Bacteria and fungi decompose dead material and return nutrients to the soil.

Q57. What happens to energy as it passes along a food chain?

  • (A) Much of it is lost at each level, so food chains are usually short
  • (B) It increases at each level
  • (C) It stays the same
  • (D) It is recycled like nutrients
Show Answer

Answer: A – Energy is lost through respiration, movement and waste, so only a small proportion passes on.

Q58. Approximately what proportion of energy is typically transferred from one trophic level to the next?

  • (A) About 90 percent
  • (B) About 10 percent
  • (C) About 50 percent
  • (D) About 100 percent
Show Answer

Answer: B – Roughly 10 percent of energy transfers between trophic levels; the rest is lost.

Q59. A pyramid of biomass shows the mass of living material at each level. Why is it usually pyramid-shaped?

  • (A) Because top predators are larger
  • (B) Because producers are smaller
  • (C) Because biomass decreases at higher levels due to energy loss
  • (D) Because decomposers are excluded
Show Answer

Answer: C – Less energy reaches higher levels, so less biomass can be supported.

Q60. In a pyramid of numbers, one large tree can support many insects. What shape might this pyramid have?

  • (A) It is always a perfect pyramid
  • (B) It has no producers
  • (C) It is always rectangular
  • (D) It can be inverted, with fewer producers than consumers
Show Answer

Answer: D – A single tree supporting many herbivores gives an inverted pyramid of numbers.

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