cheek cells and protease

Discussion in 'Supporting Biology' started by jan, Dec 5, 2018.

  1. jan


    has anyone done cheek cells using protease,salt and detergent. I have been asked for this but cannt seem to any instructions and haven't done it using protease before. This is for A level.
  2. Hi Jan. The only time I've ever known Protease (specifically Proteinase K), detergent and salt to be used with Cheek cells is in the extraction of DNA followed by amplification of specific regions of DNA by PCR. I didn't realise that this was in the A level curriculumn. This may be useful.:);) workshop presentation.pdf
  3. We use a salty detergent mixture comprising 900ml water + 30g salt + 100ml washing up liquid (cheap lab detergent is fine - helps if it's fairly 'runny').

    Protocol is to get the kids to gently chew on inside of cheek and then spit into test tube. Add equal volume of salty detergent and mix, then add a few drops of 2% pepsin.

    Stand for a few mins then slowly pour an equal quantity of ice cold ethanol down the side of the tube. DNA precipitates at the water/EtOH interface and can be collected by swirling a glass rod through it.

    We do this for our Yr 7's.