Saturday 11 December 2010

Kiwi Fruit DNA

I haven't really talked much on here about the actual subjects I teach, so it's time to remedy this. Tuesday afternoons are good times for me to do practicals with my AS Biology students (their penultimate year of high school study), and I thought it would be good fun to do a DNA extraction.

The students used kiwi fruit, but it can be done with pretty much anything living (I did caution the students against blending up their little brothers and sisters). The main hazard was giving a bunch of teenagers kitchen knives, not least because the poor darlings are so inept at food preparation that it took them ages to cut the sodding kiwis. I had a student teacher with me and remarked to him that they were all going to starve at university if this was how they cut up food. He said "No, they'll survive okay on Pot Noodles"...

We largely followed the protocol from Practical Biology, and got some pretty cool results. The bubbles in the image above are trapped in the strands of DNA, and the rather margarita-coloured substance underneath is the pulverised salty-kiwi-and-washing-up-liquid goo.

Isn't science brilliant? That's DNA, that is! In front of our very eyes.


  1. Hello, did you add pectinase or pectin enzymes to the solution?

  2. No pectinase, so some of the stringy "bits" could have been pectin as well as DNA. This method uses protease enzymes - a kitchen science version of this would be fine with meat tenderiser or contact lens solution.


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