I guess the answers in the DNA......

Another work blip today.

These are my year 10 pupils constructing DNA strands using scissors, glue and coloured pens.

How high tech is that?

Began by telling them the story of the discovery of the structure of DNA by Watson, Crick, Watkins and Rosalind Franklin and why only Watson & Crick get the credit.

Then I explained about the 4 bases A, T, C and G and how they pair up A-T, C-G and are arranged along the chromosome in triplets to code for proteins.

I told them the DNA joke...." How do you tell the sex of a chromosome?"..... "Take off its genes and have a look".........greeted by a chorus of 24 groans!

They were more impressed when I demonstrated that using the 4 bases in groups of three gave billions of possible combinations and makes us all unique.

Their task was then to cut out one half of a DNA strand and colour each base a seperate colour, a toatal of 9 bases, so three triplets, and then from a random 17 bases, select the correct matches to the half strand, colour them and stick them in the correct places to make a double helix.

They all got it right first time!

We'll see how they do next week when we move on to Gregor Mendel and monohybrid cross diagrams! It will prompt dozens of questions "Why are my eyes blue when both my parents have brown eyes?"...."What do you mean only some people can roll their tongues?"....."Test me to see if I'm colour blind!" plus having to explain that being colour blind doesn't mean you see in monochrome..... "How do you get twins then?"......" What causes Down's Syndrome?"

Like I said to the class." It ain't rocket science....but it is the second most complicated bit of science after rocket science"


There now, I bet you know more about genetics now than you ever wanted to.

Have a good weekend!