Lesson T4.1.3

T4.1.3 The DNA model and its discovery Quiz: KS3 Biology, Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

Lesson T4.1.3, The DNA model and its discovery: 20 multiple choice questions for the KS3 Biology (National Curriculum), Unit 4: Genetics and evolution, written with Revision Ninja.

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

The 20 questions

  1. Who were the scientists who built the double helix model of DNA in 1953?

    • Darwin and Wallace
    • Mendel and Morgan
    • Pasteur and Koch
    • Watson and Crick

  2. Which two scientists produced X-ray images of DNA that helped the model?

    • Wilkins and Franklin
    • Darwin and Mendel
    • Watson and Crick
    • Pasteur and Koch

  3. What technique did Franklin use to study DNA's structure?

    • Microscopy of leaves
    • Electrophoresis of blood
    • X-ray diffraction
    • Measuring pH of cells

  4. Why was the double helix model important?

    • It proved that plants do not need light to make their food and grow
    • It explained how DNA can be copied and how genetic information is passed on
    • It showed that all cells have the same shape regardless of their function
    • It explained why red blood cells lack a nucleus in mature humans

  5. Why is it important that scientists shared their data on DNA?

    • Scientists only needed their own results
    • It made the results more expensive to use
    • Others could check and build on the work
    • Data was kept secret for many decades

  6. Which feature of the model explains how DNA is copied?

    • The strands are made of protein that folds around each base
    • The sugar molecules are all the same, so each strand is identical
    • The base pairs allow each strand to act as a template
    • The helix has no chemical bonds, so the strands separate easily

  7. Which scientist's work on DNA used images of molecules created from X-ray diffraction?

    • Gregor Mendel
    • Louis Pasteur
    • Rosalind Franklin
    • Charles Darwin

  8. What does a model of DNA help students to understand?

    • How DNA's structure relates to its function
    • How the lungs exchange gases
    • How plants photosynthesise at night
    • How cells divide in plants only

  9. Why did the discovery of the DNA model take many years?

    • DNA is only found in one species of plant, so it was hard to study
    • Scientists had to combine evidence from several experiments and images
    • Scientists were not allowed to study DNA until the middle of the century
    • DNA was too large to be seen at all, even with the best microscopes

  10. What does the double helix shape of DNA look like?

    • A flat sheet
    • A solid ball
    • A twisted ladder
    • A straight tube

  11. Which scientist is associated with the theory of natural selection?

    • Gregor Mendel
    • Charles Darwin
    • Francis Crick
    • Rosalind Franklin

  12. Why did Franklin's images matter to Watson and Crick?

    • They proved that DNA is found in the cell wall
    • They revealed the exact sequence of DNA in humans
    • They showed the colour of the DNA strands
    • They provided evidence about the shape and spacing of DNA

  13. What is the approximate number of base pairs in a human genome?

    • About 300 million per chromosome pair
    • About 3 billion
    • About 300
    • About 3 thousand

  14. What do scientists mean when they say DNA carries a code?

    • The order of its bases encodes instructions for making proteins
    • DNA is written in an alphabet of numbers only, with no letters
    • DNA contains a secret message hidden in its sugar molecules
    • DNA holds water inside the nucleus and keeps the cell hydrated

  15. Why did Watson and Crick need to know how the bases paired?

    • Base pairing explains how the cell makes oxygen
    • Base pairing explains how DNA can be copied accurately
    • Base pairing explains why cells are unable to divide
    • Base pairing explains why DNA is found in the cell wall

  16. Which statement about the DNA discovery is correct?

    • It was made without any experimental evidence, using only guesses
    • It was made after researchers found that plants lack DNA in their cells
    • It was built on work by several scientists, not one person alone
    • It was made by one scientist working entirely alone in a single lab

  17. What is the main reason the DNA double helix is important today?

    • It underpins genetics, medicine and biotechnology
    • It explains how plants lose their leaves in autumn
    • It explains why rocks are formed
    • It shows how water evaporates from the sea

  18. Which of these best describes a base pair?

    • Two proteins that transport oxygen
    • Two bases that link across the two strands of DNA
    • Two sugar molecules that form a cell wall
    • Two cells that fuse in fertilisation

  19. Which base pairs with adenine in DNA?

    • Guanine
    • Thymine
    • Cytosine
    • Uracil

  20. Which base pairs with guanine in DNA?

    • Cytosine
    • Thymine
    • Adenine
    • Uracil

All KS3 Biology quizzes