A-Level Biology Practice Test 4 – 60 Questions with Answers (Cambridge 9700)
Test your A-Level understanding across all 19 topics, using each answer explanation to close any gaps before the next test.
Cell structure
Q1. Which feature distinguishes eukaryotic from prokaryotic cells?
- (A) Circular DNA
- (B) Membrane-bound organelles
- (C) A cell wall
- (D) Ribosomes
Show Answer
Answer: B – Eukaryotes have compartmentalised organelles, while prokaryotes do not.
Q2. What is the function of rough endoplasmic reticulum?
- (A) It synthesises lipids
- (B) It produces ATP
- (C) It stores water
- (D) It synthesises and transports proteins
Show Answer
Answer: D – Ribosomes on its surface make proteins for secretion or membranes.
Q3. Why are mitochondria described as having a double membrane?
- (A) They have inner and outer membranes from their evolutionary origin
- (B) They have a cell wall
- (C) They are surrounded by chloroplasts
- (D) They lack membranes
Show Answer
Answer: A – The double membrane supports the endosymbiotic theory.
Biological molecules
Q4. Which disaccharide is formed from glucose and fructose?
- (A) Maltose
- (B) Lactose
- (C) Sucrose
- (D) Cellulose
Show Answer
Answer: C – Sucrose is the transport sugar in many plants.
Q5. What is the difference between alpha and beta glucose?
- (A) The number of carbon atoms
- (B) The presence of nitrogen
- (C) The position of the hydroxyl group on carbon 1
- (D) The molecular mass
Show Answer
Answer: C – Alpha and beta isomers differ in orientation at carbon 1.
Q6. Which lipid is a major component of cell membranes?
- (A) Phospholipid
- (B) Triglyceride only
- (C) Steroid only
- (D) Wax only
Show Answer
Answer: A – Phospholipids form the bilayer of membranes.
Enzymes
Q7. What is an enzyme-substrate complex?
- (A) A permanent product
- (B) An inhibitor bound forever
- (C) A denatured enzyme
- (D) A temporary association during catalysis
Show Answer
Answer: D – The complex forms, reacts, and releases products, leaving the enzyme unchanged.
Q8. Which graph shows enzyme activity against pH?
- (A) A straight line increasing forever
- (B) A bell-shaped curve with an optimum
- (C) A plateau at all pH values
- (D) A curve decreasing to zero only
Show Answer
Answer: B – Activity rises to an optimum, then falls as denaturation occurs.
Q9. Why are enzymes specific?
- (A) They are large molecules
- (B) They work at all temperatures
- (C) They are made of lipids
- (D) Their active site shape matches only certain substrates
Show Answer
Answer: D – Shape complementarity restricts which substrates can bind.
Cell membranes and transport
Q10. A plant cell is placed in a concentrated sucrose solution. Water leaves the cell and the protoplast shrinks away from the wall. Which process is occurring across the cell surface membrane?
- (A) Movement of solutes against a gradient
- (B) Movement of water using ATP
- (C) Osmosis, movement of water down its water potential gradient through a partially permeable membrane
- (D) Diffusion of ions through channels
Show Answer
Answer: C – Osmosis is passive water movement across a membrane, from higher to lower water potential.
Q11. Which organelle is involved in exocytosis?
- (A) The nucleus
- (B) The Golgi apparatus
- (C) The ribosome
- (D) The chloroplast
Show Answer
Answer: B – Golgi vesicles carry material to the membrane for release.
Q12. What happens to a plant cell in pure water?
- (A) It becomes turgid but does not burst
- (B) It bursts immediately
- (C) It becomes plasmolysed
- (D) It loses all water
Show Answer
Answer: A – The cell wall resists pressure, so the cell becomes turgid.
The mitotic cell cycle
Q13. What is the purpose of mitosis in growth?
- (A) It produces genetically identical cells for growth and repair
- (B) It produces gametes
- (C) It increases genetic variation
- (D) It halves chromosome number
Show Answer
Answer: A – Mitosis maintains chromosome number in daughter cells.
Q14. Which phase follows metaphase in mitosis?
- (A) Prophase
- (B) Anaphase
- (C) Telophase
- (D) Interphase
Show Answer
Answer: B – Anaphase separates sister chromatids.
Q15. What is a chromatid?
- (A) A whole chromosome before replication
- (B) A spindle fibre
- (C) One of two identical copies of a chromosome after replication
- (D) A nuclear membrane fragment
Show Answer
Answer: C – Sister chromatids are joined at the centromere.
Nucleic acids and protein synthesis
Q16. What is semi-conservative replication?
- (A) Both strands are completely new
- (B) Both strands are completely old
- (C) DNA is copied by RNA only
- (D) Each new DNA molecule contains one old and one new strand
Show Answer
Answer: D – Meselson and Stahl supported semi-conservative replication.
Q17. What is the role of tRNA?
- (A) It copies DNA
- (B) It forms the ribosome alone
- (C) It splices mRNA
- (D) It brings a specific amino acid to the ribosome
Show Answer
Answer: D – Each tRNA has an anticodon matching an mRNA codon.
Q18. Which process removes introns?
- (A) Splicing
- (B) Translation
- (C) Replication
- (D) Transcription initiation
Show Answer
Answer: A – Splicing produces mature mRNA containing only exons.
Transport in plants
Q19. Which cells load sucrose into phloem?
- (A) Xylem vessels
- (B) Guard cells
- (C) Companion cells using active transport
- (D) Sieve tube elements alone
Show Answer
Answer: C – Companion cells actively load sucrose, creating a gradient.
Q20. What is the Casparian strip?
- (A) A layer in the leaf cuticle
- (B) A waterproof band in the endodermis forcing water through cells
- (C) A part of the phloem
- (D) A root hair structure
Show Answer
Answer: B – The strip blocks apoplast movement, controlling uptake.
Q21. Which route does water take through cell walls?
- (A) The symplast pathway only
- (B) The apoplast pathway
- (C) The vacuolar pathway only
- (D) The phloem pathway
Show Answer
Answer: B – Apoplast movement occurs through cell walls and spaces.
Transport in mammals
Q22. What is the function of the sinoatrial node?
- (A) It prevents backflow
- (B) It carries oxygenated blood
- (C) It initiates the heartbeat as the pacemaker
- (D) It filters blood
Show Answer
Answer: C – The SAN sets the rhythm of atrial contraction.
Q23. Which vessel carries blood from the heart to the body?
- (A) The aorta
- (B) The pulmonary vein
- (C) The vena cava
- (D) The renal vein
Show Answer
Answer: A – The aorta distributes oxygenated blood systemically.
Q24. Fluid collected from around body cells is analysed. It resembles plasma but contains very few proteins and no cells. What is this fluid?
- (A) Blood inside capillaries
- (B) Lymph in lymph nodes only
- (C) Fluid inside red blood cells
- (D) Tissue fluid, bathing cells and formed from blood plasma
Show Answer
Answer: D – Tissue fluid supplies cells and collects waste, and is formed from plasma that leaves capillaries.
Gas exchange
Q25. What is ventilation?
- (A) Diffusion across alveoli
- (B) Transport of oxygen in blood
- (C) Movement of air in and out of the lungs
- (D) Cellular respiration
Show Answer
Answer: C – Ventilation maintains gas gradients in the lungs.
Q26. Which gas diffuses fastest across the alveolar wall?
- (A) Oxygen diffuses faster than carbon dioxide
- (B) Nitrogen diffuses fastest
- (C) Both gases diffuse equally
- (D) Carbon dioxide diffuses faster than oxygen
Show Answer
Answer: D – Carbon dioxide is more soluble, so it diffuses more rapidly.
Q27. What is the role of haemoglobin in carbon dioxide transport?
- (A) It carries oxygen only
- (B) It forms carbamino compounds with carbon dioxide
- (C) It buffers pH only in plasma
- (D) It transports glucose
Show Answer
Answer: B – Some carbon dioxide binds directly to haemoglobin.
Infectious diseases
Q28. Which disease is caused by a virus?
- (A) Influenza
- (B) Cholera
- (C) Tuberculosis
- (D) Malaria
Show Answer
Answer: A – Influenza is caused by a virus infecting respiratory cells.
Q29. What is a pathogen?
- (A) An organism that causes disease
- (B) A type of white blood cell
- (C) An antibody
- (D) A vaccine component
Show Answer
Answer: A – Pathogens include bacteria, viruses, fungi and protoctists.
Q30. How does HIV weaken immunity?
- (A) It increases antibody production
- (B) It blocks phagocytosis only
- (C) It causes red blood cells to burst
- (D) It destroys helper T cells
Show Answer
Answer: D – Loss of helper T cells impairs coordination of immunity.
Q31. Which antibiotic action is correct?
- (A) Penicillin kills viruses
- (B) Penicillin increases bacterial growth
- (C) Penicillin inhibits bacterial cell wall synthesis
- (D) Penicillin replaces antibodies
Show Answer
Answer: C – Blocking wall synthesis causes bacterial lysis.
Immunity
Q32. A transplanted organ is rejected because the recipient’s lymphocytes recognise proteins on its cells as foreign. What name is given to these foreign molecules?
- (A) An antibody
- (B) An antigen, a molecule that triggers an immune response
- (C) A type of phagocyte
- (D) A vaccine virus only
Show Answer
Answer: B – Antigens are recognised as foreign by lymphocytes, triggering a specific immune response.
Q33. What is the primary immune response?
- (A) A faster response on second exposure
- (B) The first response to an antigen, slower and smaller
- (C) Immunity from injected antibodies
- (D) A response that never produces memory
Show Answer
Answer: B – The primary response produces fewer antibodies over a longer time.
Q34. How do antibodies help destroy pathogens?
- (A) They agglutinate pathogens and mark them for phagocytosis
- (B) They directly digest pathogens
- (C) They produce memory cells alone
- (D) They block all blood flow
Show Answer
Answer: A – Antibodies aid recognition and removal by phagocytes.
Q35. What is autoimmunity?
- (A) An immune response to a vaccine
- (B) Lack of any immune response
- (C) Immunity to all pathogens
- (D) An immune response against the body’s own tissues
Show Answer
Answer: D – Autoimmune disorders arise when self-tolerance fails.
Energy and respiration
Q36. What is the Krebs cycle?
- (A) A reaction that fixes carbon dioxide
- (B) A stage of photosynthesis
- (C) A series of reactions that oxidises acetyl CoA and produces reduced carriers
- (D) A reaction in the cytoplasm only
Show Answer
Answer: C – The Krebs cycle releases carbon dioxide and generates NADH and FADH2.
Q37. What is oxidative phosphorylation?
- (A) ATP synthesis by direct phosphate transfer only
- (B) Breakdown of glucose in the cytoplasm
- (C) Photolysis of water
- (D) ATP synthesis using energy from the electron transport chain
Show Answer
Answer: D – Oxidative phosphorylation couples electron flow to ATP production.
Q38. Which compound is regenerated in the Krebs cycle?
- (A) Pyruvate
- (B) Oxaloacetate
- (C) Glucose
- (D) Lactate
Show Answer
Answer: B – Oxaloacetate combines with acetyl CoA to start each turn.
Q39. What happens during anaerobic respiration in yeast?
- (A) Glucose is converted to ethanol and carbon dioxide
- (B) Glucose is converted to lactate
- (C) Glucose is fully oxidised
- (D) No ATP is produced
Show Answer
Answer: A – Yeast fermentation regenerates NAD for glycolysis.
Photosynthesis
Q40. Which factor is limiting when light intensity is high but carbon dioxide is low?
- (A) Light intensity
- (B) Temperature only
- (C) Carbon dioxide concentration
- (D) Water only
Show Answer
Answer: C – The scarcest factor limits the overall rate.
Q41. What is a photosystem?
- (A) A type of chloroplast
- (B) A Calvin cycle enzyme
- (C) A cluster of pigments and proteins that absorbs light
- (D) A stomatal structure
Show Answer
Answer: C – Photosystems capture light energy for photochemistry.
Q42. Which molecule is produced by cyclic photophosphorylation?
- (A) Reduced NADP
- (B) ATP only
- (C) Oxygen
- (D) Glucose
Show Answer
Answer: B – Cyclic flow recycles electrons to produce ATP without NADP reduction.
Homeostasis
Q43. What is osmoregulation?
- (A) Control of blood glucose only
- (B) Control of body temperature only
- (C) Control of heart rate
- (D) Control of water and solute balance in the body
Show Answer
Answer: D – Osmoregulation maintains water potential of body fluids.
Q44. Which part of the nephron creates a salt gradient in the medulla?
- (A) The loop of Henle
- (B) The glomerulus
- (C) The Bowman’s capsule
- (D) The ureter
Show Answer
Answer: A – The loop establishes a gradient for water reabsorption.
Q45. What triggers glucagon release?
- (A) Low blood glucose concentration
- (B) High blood glucose concentration
- (C) High ADH levels
- (D) Low body temperature
Show Answer
Answer: A – Glucagon promotes glycogenolysis and gluconeogenesis.
Control and coordination
Q46. What is the function of the myelin sheath?
- (A) It carries impulses to muscles
- (B) It produces neurotransmitters
- (C) It insulates the axon and speeds conduction
- (D) It receives stimuli
Show Answer
Answer: C – Myelin is formed by Schwann cells in peripheral nerves.
Q47. What happens at the end of an action potential?
- (A) Sodium channels remain open permanently
- (B) The neurone dies
- (C) The impulse reverses direction
- (D) The membrane repolarises as potassium channels open
Show Answer
Answer: D – Potassium efflux restores the resting potential.
Q48. What is thigmotropism?
- (A) Growth towards light
- (B) Growth in response to touch
- (C) Growth towards water
- (D) Growth away from gravity
Show Answer
Answer: B – Thigmotropism is seen in tendrils wrapping around supports.
Inheritance
Q49. What is a pedigree diagram used for?
- (A) Measuring allele frequencies only
- (B) Tracing inheritance of a trait through a family
- (C) Cloning organisms
- (D) Sequencing DNA
Show Answer
Answer: B – Pedigrees show phenotypes across generations.
Q50. What is incomplete dominance?
- (A) One allele completely masks another
- (B) Both alleles are fully expressed
- (C) No phenotype is expressed
- (D) The heterozygote shows an intermediate phenotype
Show Answer
Answer: D – Intermediate phenotypes arise when neither allele is fully dominant.
Q51. What is the expected phenotypic ratio for a dihybrid cross with complete dominance?
- (A) 1:1:1:1
- (B) 3:1
- (C) 9:3:3:1
- (D) 1:2:1
Show Answer
Answer: C – Independent assortment gives the classic dihybrid ratio.
Selection and evolution
Q52. In a population of beetles, green beetles are better camouflaged on leaves than brown beetles, so green beetles leave more offspring. Over generations, green becomes more common. Which process is this?
- (A) Natural selection, differential survival and reproduction due to inherited variation
- (B) Random change in allele frequencies only
- (C) Artificial breeding by humans
- (D) Mutation alone
Show Answer
Answer: A – Selection increases advantageous alleles over generations as better-adapted individuals reproduce more.
Q53. Which statement about antibiotic resistance is correct?
- (A) Antibiotics create resistant genes directly
- (B) All bacteria become resistant immediately
- (C) Resistance cannot be inherited
- (D) It evolves by selection of resistant bacteria
Show Answer
Answer: D – Pre-existing resistant variants survive antibiotic treatment.
Q54. What is an example of convergent evolution?
- (A) Similar traits evolving independently in unrelated species
- (B) Identical species evolving together
- (C) Speciation by isolation only
- (D) Extinction of similar species
Show Answer
Answer: A – Convergent traits arise from similar selection pressures.
Classification, biodiversity and conservation
Q55. What is a phylogenetic tree?
- (A) A food web diagram
- (B) A diagram showing evolutionary relationships
- (C) A classification of habitats
- (D) A map of species distribution
Show Answer
Answer: B – Phylogenetic trees are based on shared characteristics and DNA.
Q56. Which method estimates population size by marking and recapture?
- (A) Simpson’s index
- (B) Chi-squared test
- (C) The Lincoln index
- (D) Quadrats only
Show Answer
Answer: C – Marked individuals are released and the proportion recaptured estimates total size.
Q57. What is sustainable management?
- (A) Using resources at a rate that allows replenishment
- (B) Using all resources immediately
- (C) Protecting one species only
- (D) Preventing all human use
Show Answer
Answer: A – Sustainability balances use with long-term availability.
Genetic technology
Q58. What is the purpose of gel electrophoresis in DNA profiling?
- (A) To amplify DNA
- (B) To cut DNA
- (C) To separate DNA fragments by size
- (D) To join DNA fragments
Show Answer
Answer: C – Fragments move through gel according to size and charge.
Q59. Which enzyme seals DNA fragments in genetic engineering?
- (A) Restriction enzyme
- (B) DNA ligase
- (C) DNA polymerase
- (D) RNA polymerase
Show Answer
Answer: B – Ligase forms phosphodiester bonds between fragments.
Q60. What is a potential benefit of genetically modified crops?
- (A) Reduced genetic diversity always
- (B) No need for water
- (C) Guaranteed higher nutrition in every case
- (D) Increased yield or pest resistance
Show Answer
Answer: D – GM traits can improve yield, resistance or nutrition.
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