DNA practical

• Extracting DNA from fruit


  1. grind fruit in pestle and mortar to break open cells and release DNA

  2. Transfer to beaker

  3. Add detergent to break down cell and nuclear membranes

  4. Add salt to make DNA stick together

  5. Stir

  6. Filter using sieve to remove insoluble material

  7. Carefully add ice cold ethanol down the side of the container

  8. Ethanol makes DNA precipitate and form a solid

  9. Collect the DNA using a glass rod or similar
• Extracting DNA from fruit


  • Crush/grind fruit to break open cells
  • Add detergent to break down cell and nuclear membranes
  • Add salt to make DNA stick together
  • Can add protease enzymes to help remove proteins DNA is wound around
  • Filter to remove insoluble parts
  • Add ice cold ethanol to make DNA precipitate out of solution
• Common fruits used for DNA extraction are kiwi, banana, and strawberry
• The extracted DNA looks like wet cotton wool
• The extracted DNA cannot be viewed under a school microscope as the DNA structure is too small
• the protease enzymes also break down proteins in the cell membrane and the membrane around the nucleus (nuclear membrane). This helps to release the DNA