GCSE Biology Practice Test 6 – 60 Questions with Answers (AQA 8461)

Q1. What is the main function of mitochondria in a cell?

• (A) To release energy from glucose by aerobic respiration
• (B) To make proteins for the cell
• (C) To control all cell activities
• (D) To store water and dissolved substances

Q2. A drawing of a cell is 20 mm long. The real cell is 0.05 mm long. What is the magnification of the drawing?

• (A) 40
• (B) 1000
• (C) 400
• (D) 4

Q3. Which part of an animal cell controls the activities of the cell?

• (A) Cell membrane
• (B) Cytoplasm
• (C) Nucleus
• (D) Ribosome

Q4. Which statement best describes diffusion?

• (A) The movement of water across a partially permeable membrane
• (B) The movement of particles against a concentration gradient using energy
• (C) The movement of particles that requires a carrier protein and energy
• (D) The net movement of particles from a region of higher concentration to a region of lower concentration

Q5. During osmosis, in which direction does water move?

• (A) From a concentrated solution to a dilute solution across a partially permeable membrane
• (B) From a region of low water concentration to high water concentration
• (C) From a dilute solution to a more concentrated solution across a partially permeable membrane
• (D) In both directions at exactly the same rate with no net movement

Q6. Why does active transport in root hair cells require energy?

• (A) Because mineral ions are taken up against a concentration gradient
• (B) Because water moves into the root by osmosis
• (C) Because root hair cells have a large surface area
• (D) Because diffusion is too slow in soil water

Q7. What does mitosis produce?

• (A) Four genetically different haploid cells
• (B) Two genetically different diploid cells
• (C) Four genetically identical diploid cells
• (D) Two genetically identical diploid cells

Q8. Adult stem cells in bone marrow are able to develop into which type of cell?

• (A) Nerve cells only
• (B) Blood cells
• (C) Muscle cells only
• (D) Plant root cells

Q9. Which feature is found in a bacterial cell but is not found in an animal cell?

• (A) A nucleus
• (B) A mitochondrion
• (C) A cell membrane
• (D) A plasmid

Q10. What does amylase break down, and into what?

• (A) Protein into amino acids
• (B) Lipid into fatty acids and glycerol
• (C) Sugar into starch
• (D) Starch into sugars

Q11. Protease enzymes break down proteins into which substances?

• (A) Fatty acids and glycerol
• (B) Simple sugars
• (C) Starch molecules
• (D) Amino acids

Q12. What is the product of lipid digestion by lipase?

• (A) Fatty acids and glycerol
• (B) Amino acids
• (C) Glucose
• (D) Starch

Q13. Which statement describes a function of bile?

• (A) It breaks starch into sugars
• (B) It carries oxygen around the body
• (C) It emulsifies fats and neutralises stomach acid
• (D) It produces insulin for blood glucose control

Q14. Which side of the heart pumps blood to the lungs, and at what pressure compared with the body circulation?

• (A) The right side, at lower pressure
• (B) The left side, at lower pressure
• (C) The right side, at higher pressure
• (D) Both sides at equal pressure

Q15. Which adaptation of red blood cells helps them carry oxygen?

• (A) They contain a large nucleus
• (B) They have a thick cell wall
• (C) They can divide by mitosis in the blood
• (D) They contain haemoglobin and have no nucleus

Q16. Which feature is characteristic of arteries?

• (A) Thin walls with valves to prevent backflow
• (B) Thick, muscular, elastic walls that withstand high pressure
• (C) A very large surface area for exchange
• (D) Walls one cell thick

Q17. Which plant tissue transports water and mineral ions from the roots to the leaves?

• (A) Phloem
• (B) Xylem
• (C) Mesophyll
• (D) Epidermis

Q18. What is the function of guard cells in a leaf?

• (A) They open and close stomata to control gas exchange and water loss
• (B) They carry out most photosynthesis
• (C) They transport sugars to the roots
• (D) They absorb water from the soil

Q19. Salmonella bacteria cause food poisoning. How do they usually enter the body?

• (A) Through cuts in the skin only
• (B) By insect bites
• (C) In contaminated food or water
• (D) Through the lungs in the air

Q20. Why do antibiotics not cure a cold caused by a virus?

• (A) Viruses are too large for antibiotics to reach
• (B) Antibiotics only work in the stomach
• (C) Viruses are killed by vaccines instead of drugs
• (D) Antibiotics kill bacteria, not viruses

Q21. During phagocytosis, what does a white blood cell do?

• (A) It produces antibodies in the blood
• (B) It engulfs and digests a pathogen
• (C) It releases antitoxins into the plasma
• (D) It copies the pathogen to make a vaccine

Q22. Why is a second dose, or booster, of a vaccine sometimes given?

• (A) The first dose kills the pathogen directly
• (B) To replace antibodies used up by the skin
• (C) To strengthen the immune response and increase memory cells
• (D) To cure the disease if the first dose fails

Q23. Which practice increases the risk of antibiotic-resistant bacteria spreading?

• (A) Taking the full prescribed course
• (B) Using antibiotics only for bacterial infections
• (C) Washing hands before handling food
• (D) Stopping a course of antibiotics early

Q24. In drug development, what is the purpose of a double-blind trial?

• (A) To test the drug on twice as many animals
• (B) To check the drug works in two countries at once
• (C) To prevent bias because neither patients nor doctors know who receives the real drug
• (D) To give every patient two different drugs

Q25. Malaria is caused by which type of pathogen?

• (A) A bacterium
• (B) A virus
• (C) A protist
• (D) A fungus

Q26. Why is each antibody specific to one antigen?

• (A) Its shape is complementary to that antigen
• (B) It is produced only in the bone marrow
• (C) It contains a copy of the pathogen DNA
• (D) It changes shape to fit any pathogen

Q27. Which substance is taken in by a leaf for photosynthesis?

• (A) Carbon dioxide
• (B) Oxygen
• (C) Glucose
• (D) Ethanol

Q28. A student increases light intensity but the rate of photosynthesis stops rising. What is the most likely explanation?

• (A) The plant has run out of chlorophyll
• (B) Another factor, such as carbon dioxide concentration or temperature, is now limiting the rate
• (C) Photosynthesis has stopped completely
• (D) Light intensity no longer affects the rate at any level

Q29. During respiration, which molecule is broken down to release energy?

• (A) Oxygen
• (B) Glucose
• (C) Carbon dioxide
• (D) Water

Q30. During vigorous exercise, muscles may respire anaerobically. What is produced in muscle cells?

• (A) Ethanol and carbon dioxide
• (B) Glucose and oxygen
• (C) Carbon dioxide and water only
• (D) Lactic acid

Q31. Yeast respiring anaerobically produces which substances?

• (A) Lactic acid and water
• (B) Ethanol and carbon dioxide
• (C) Glucose and oxygen
• (D) Ethanol and oxygen

Q32. Why do heart rate and breathing rate increase during exercise?

• (A) To reduce the amount of blood reaching the muscles
• (B) To supply more oxygen and glucose to muscles and remove more carbon dioxide
• (C) To slow down respiration in muscle cells
• (D) To store glycogen in the liver

Q33. A leaf is thin. How does this help photosynthesis?

• (A) It prevents all water loss from the leaf
• (B) It increases the distance light must travel
• (C) It stops the leaf absorbing light
• (D) It gives a short diffusion distance for carbon dioxide and oxygen

Q34. Which process releases energy from glucose without using oxygen in a muscle cell, and is less efficient than aerobic respiration?

• (A) Anaerobic respiration
• (B) Photosynthesis
• (C) Digestion
• (D) Osmosis

Q35. Which sequence correctly describes a reflex arc?

• (A) Effector -> motor neurone -> relay neurone -> sensory neurone -> receptor
• (B) Receptor -> sensory neurone -> relay neurone -> motor neurone -> effector
• (C) Receptor -> motor neurone -> relay neurone -> sensory neurone -> effector
• (D) Sensory neurone -> receptor -> motor neurone -> relay neurone -> effector

Q36. What makes up the central nervous system?

• (A) The brain and all sensory receptors
• (B) The spinal cord and all motor neurones
• (C) All nerves in the arms and legs
• (D) The brain and the spinal cord

Q37. What happens at a synapse?

• (A) An electrical impulse jumps directly between bones
• (B) A chemical transmitter diffuses across a small gap to the next neurone
• (C) A hormone travels in the blood to a target organ
• (D) The impulse stops and does not continue

Q38. What is the effect of insulin on blood glucose concentration?

• (A) It raises blood glucose by breaking down glycogen
• (B) It has no effect on blood glucose
• (C) It lowers blood glucose by increasing uptake into cells and conversion to glycogen
• (D) It converts glucose directly into fat only

Q39. Which effect does adrenaline have during a stressful situation?

• (A) It decreases heart rate and breathing rate
• (B) It lowers blood glucose concentration
• (C) It causes the pupils to constrict
• (D) It increases heart rate and blood flow to muscles

Q40. When the water content of the blood falls, what happens involving ADH?

• (A) Less ADH is released and the kidney reabsorbs less water
• (B) ADH causes the kidney to excrete more water
• (C) More ADH is released, the kidney reabsorbs more water, and a small volume of concentrated urine is produced
• (D) ADH stops the kidney filtering blood

Q41. On a hot day, how does the body increase heat loss from the skin?

• (A) Blood vessels constrict and hairs lie flat
• (B) Shivering increases in the muscles
• (C) Blood vessels dilate and sweat evaporates from the skin surface
• (D) Sweat glands stop producing sweat

Q42. A seedling root grows downwards. How does auxin affect the root to produce this response?

• (A) Auxin on the lower side inhibits elongation there, so the root bends downwards
• (B) Auxin on the upper side stops all growth
• (C) Auxin makes the lower side grow faster than the upper side
• (D) Auxin blocks the root from detecting gravity

Q43. How many copies of most genes does a body cell have?

• (A) One
• (B) Four
• (C) None, genes are found only in gametes
• (D) Two, one on each homologous chromosome

Q44. An organism has genotype Bb for eye colour, where B is dominant. Which allele is recessive?

• (A) BB
• (B) b
• (C) The phenotype
• (D) Both alleles equally

Q45. What is meant by phenotype?

• (A) The combination of alleles an organism carries
• (B) The observable characteristics of an organism, resulting from genotype and environment
• (C) The number of chromosomes in a gamete
• (D) The DNA sequence of one gene only

Q46. A heterozygous parent (Hh) is crossed with a homozygous recessive parent (hh). What percentage of offspring is expected to be hh?

• (A) 50%
• (B) 25%
• (C) 75%
• (D) 100%

Q47. What determines whether a human baby is male or female?

• (A) Whether the egg carries an X or a Y chromosome
• (B) The temperature during pregnancy
• (C) The number of chromosomes in the mother
• (D) Whether the sperm carries an X or a Y chromosome

Q48. Height in humans is an example of which type of variation?

• (A) Discontinuous variation, controlled by a single gene only
• (B) Variation caused only by the environment
• (C) Continuous variation, influenced by genes and environment
• (D) Variation that cannot be inherited

Q49. Peppered moths: dark moths became common in polluted areas. Which explanation fits natural selection?

• (A) Soot changed each moth’s genes during its lifetime
• (B) Dark moths were camouflaged on soot-darkened trees, survived predation better and passed on dark alleles
• (C) Birds chose to eat only pale moths because they tasted better
• (D) Moths decided to become darker

Q50. Selective breeding involves humans doing what over many generations?

• (A) Inserting genes from another species into an organism
• (B) Allowing only random mating with no selection
• (C) Choosing organisms with desired characteristics to breed together
• (D) Cloning organisms in a laboratory

Q51. Genetic modification of bacteria to produce human insulin involves what?

• (A) Breeding bacteria with human cells
• (B) Inserting the human insulin gene into bacterial DNA so the bacteria make insulin
• (C) Treating bacteria with antibiotics until they make insulin
• (D) Removing all plasmids from the bacteria

Q52. In a food chain, what is the role of a producer?

• (A) It makes its own food, usually by photosynthesis, and is eaten by consumers
• (B) It eats other animals for energy
• (C) It breaks down dead material only
• (D) It is always at the top of the food chain

Q53. Why does biomass usually decrease at each higher trophic level?

• (A) Consumers at higher levels eat less food
• (B) Producers produce less biomass each year
• (C) Energy is lost through respiration, excretion, egestion and movement
• (D) Decomposers remove all biomass from higher levels

Q54. Which process in the carbon cycle releases carbon dioxide back into the air?

• (A) Respiration
• (B) Photosynthesis
• (C) Fossilisation
• (D) Sedimentation

Q55. What do decomposers do in an ecosystem?

• (A) They break down dead organisms and waste, returning nutrients to the soil
• (B) They produce food for herbivores
• (C) They eat only living producers
• (D) They remove carbon dioxide from the air

Q56. Large areas of peat bog are drained for farming. Why does this increase atmospheric carbon dioxide?

• (A) Peat absorbs oxygen from the air
• (B) Farming uses more sunlight
• (C) Bog plants stop respiring
• (D) Stored carbon in peat is oxidised by decomposers and released as carbon dioxide

Q57. Which human activity increases methane in the atmosphere?

• (A) Planting trees
• (B) Keeping large numbers of cattle and using landfill sites
• (C) Using wind turbines
• (D) Reducing fertiliser use

Q58. Fertiliser washing into a lake can cause eutrophication. What happens next?

• (A) Algae grow rapidly, block light, then die and are decomposed, using up oxygen in the water
• (B) Fish populations increase because of extra oxygen
• (C) The water becomes clearer and cleaner
• (D) Plants on the lake bed grow faster due to more light

Q59. Which action helps conserve biodiversity?

• (A) Protecting habitats and setting up seed banks
• (B) Draining wetlands for farmland
• (C) Removing all predators from an ecosystem
• (D) Introducing non-native species everywhere

Q60. Why should quadrats be placed randomly when sampling plants?

• (A) To make sure the rarest plants are always found
• (B) To sample only the largest plants
• (C) To avoid bias and obtain a representative sample
• (D) To avoid counting any plant twice