Exploding conical flask Protocol

DNA From onions

Materials

  • Liquidizer
  • Sharp vegetable knife and chopping board
  • Water Bath set at 60 degres centigrade
  • Ice, in a jug
  • Thermometer
  • 250 cm3 beakers (2)
  • Coffee filter paper
  • Onion (100g)
  • Washing up liquid 10 cm3(Not the concentrated one)
  • Sodium chloride (3g)
  • Distilled Water
  • Sender Glass rod
  • 10cm3 syringe
  • Boiling tube
  • Rack to hold the tubes
  • Protease enzyme, (Novo Neutrase)
  • Ice cold ethanol 95% (9cm3) (placed in the freezer overnight)

    Operations

  • 1) Add the sodium chloride to the washing up liquid, Make up to 100cm3 with distilled water.
  • 2) Cut the onion into small pieces. Place them in the beacher then pour the detergent / salt solution
  • 3) Stir the mixture and maintain in a 60 degrees centigrade water bath for 15 minutes.
  • 4) Cool the mixture in an ice water bath for 5 minutes, stirring frequently
  • 5) Pour the mixture in the liquidizer and blend for five seconds on high speed
  • 6) Filter the mixture into the second beaker. Do not contaminate the filtrate with the foam from the surface.
  • 7) Add the enzyme to the onion extract (2 or 3 drops) in a boiling tube, mixing well.
  • 8) Form a layer of ice cold ethanol on top of the onion extract / protease mixture by pouring it slowly down the side of the boiling tube. Leave the tube for 2-3 minutes without disturbing it.
  • 9 ) Gently rotate the glass rod in the liquid at the interface of the alcohol and the detergent. take care not to mix the solutions too much.