DNA core practical

• Step 1: mash the fruit (kiwis or strawberries)

  • this breaks up the cells
• Step 2: add detergent and salt

  • this clumps DNA and breaks cell membranes
• Step 3: filter

  • to remove any insoluble substances
• Step 4: add ice-cold ethanol

  • to precipitate the DNA
• Step 5: observe the layer of white precipitate

  • and extract if required
• You could do this in a water bath to control the temperature.
• This practical is to form DNA.

  
• Independent Variable = type of fruit, concentration of solution or the temperature
• Dependent Variable = amount or consistency of DNA
• Control variable = amount of ethanol, amount of detergent or type of fruit
• We use kiwi or strawberry becuase they are soft and easy to crush.