Dr. Simple was explaining a little about DNA in the last post, so I thought I would share one of the first experiments my children ever asked me to do with them…. they wanted to see DNA, so we extracted it from a banana.
You will need…
… a banana, a fork, a bowl, washing up liquid, ice cold surgical spirits (or isopropanol – both available from a pharmacy), salt, a sieve, a glass jar.
What to do…
Remove the banana skin and mash the banana in the bowl, using the fork. Add two teaspoons of washing up liquid and stir slowly.
Add a teaspoon of salt and one to two tablespoons of water and stir carefully.
You want to avoid making bubbles.
Leave for five minutes then strain carefully through the sieve into the jar.
Tilt the glass jar and carefully pour the surgical spirits down the side of the jar, at least as thick as the banana layer. This will form a separate layer on top of the banana mixture.
Do not mix.
After five to ten minutes you will see a long, stringy substance appear in the top layer. This is the banana’s DNA.
You can use a tooth pick to lift and examine the DNA.
So what is happening?
The salt and washing up liquid break open the banana cells, releasing the DNA.
The DNA will not dissolve in the surgical spirits (or any alcohol) so it floats in this layer.
Here are a five fantastic facts about DNA…
The experiment described above is just a quick and simple method that I have used before but if you want something more scientific and a lot more fun… check out Cell Explorers! They do amazing school visits, for junior infants right up to secondary level students, which I am sure would be of interest to teacher or parents making suggestions in their own schools. Run by Dr. Muriel Grenon and her wonderful team of students and graduates these activities are really top class! Contact them by email at cellexplorers@nuigalway.ie
