Lesson 3.8.4.1.2

3.8.4.1.2 Amplifying DNA: PCR and in vivo cloning Quiz: AQA Biology, Unit 8

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.8.4.1.2, Amplifying DNA: PCR and in vivo cloning: 20 multiple choice questions for the AQA Biology (7402), Unit 8: The control of gene expression, written with Revision Ninja.

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The 20 questions

  1. Which term describes amplifying DNA fragments outside of a living organism?

    • In vivo cloning
    • In vitro cloning
    • Cellular transformation
    • Gene therapy

  2. Which step of PCR separates the two strands of DNA?

    • Ligation
    • Denaturation
    • Extension
    • Annealing

  3. What feature of Taq polymerase makes it suitable for use in PCR?

    • RNA synthesis activity
    • Low optimum temperature
    • Thermostability
    • Proofreading ability

  4. Where does DNA replication occur during in vivo cloning?

    • Inside living cells
    • In test tubes
    • Inside PCR tubes
    • On agar plates

  5. What are the short single strands of DNA used to initiate PCR?

    • Primers
    • Plasmids
    • Vectors
    • Promoters

  6. After n cycles of PCR starting from one molecule of DNA, how many copies are made?

    • n copies
    • 2^n copies
    • n^2 copies
    • 2n copies

  7. Which process is an example of an in vivo DNA cloning method?

    • Gel electrophoresis
    • Polymerase chain reaction
    • DNA sequencing
    • Bacterial transformation

  8. How many copies of a DNA molecule are made after 10 cycles of PCR starting from one molecule?

    • 100
    • 1024
    • 512
    • 20

  9. What occurs during the annealing step of PCR?

    • Phosphodiester bonds break
    • DNA polymerase denatures
    • DNA strands separate
    • Primers bind DNA

  10. Which enzyme synthesises complementary DNA strands during the extension step of PCR?

    • Restriction endonuclease
    • DNA ligase
    • Reverse transcriptase
    • DNA polymerase

  11. Five molecules of DNA undergo four cycles of PCR. How many molecules are produced?

    • 80
    • 20
    • 160
    • 40

  12. What is a key advantage of in vivo cloning compared to PCR?

    • Low contamination risk
    • Rapid amplification speed
    • No host cells needed
    • High temperature requirement

  13. Why are bacteria ideally suited as host cells for in vivo cloning?

    • Lack of DNA
    • Multicellular structure
    • Inability to mutate
    • Rapid cell division

  14. What is the main purpose of a marker gene in a cloning vector?

    • Cutting DNA fragments
    • Starting transcription
    • Denaturing target DNA
    • Identifying transformed cells

  15. Why is PCR preferred over in vivo cloning for forensic DNA samples?

    • Protein synthesis
    • Marker gene selection
    • Rapid amplification
    • Host cell requirement

  16. What is the minimum number of PCR cycles needed to produce at least 1000 copies starting from one molecule?

    • 5
    • 100
    • 8
    • 10

  17. What is the correct sequence of stages in one PCR cycle?

    • Extension, annealing, denaturation
    • Denaturation, extension, annealing
    • Annealing, denaturation, extension
    • Denaturation, annealing, extension

  18. What chemical group must primers provide for DNA polymerase to bind?

    • 5' phosphate
    • Amino group
    • Ribose sugar
    • 3' hydroxyl

  19. What happens if the PCR annealing temperature is set too high?

    • Nucleotides degrade
    • Polymerase denatures
    • DNA denatures instantly
    • Primers fail to bind

  20. What is an advantage of in vivo cloning over PCR for gene production?

    • Uses higher temperatures
    • Faster reaction speed
    • Requires no vectors
    • Produces living cultures

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