Professor Sykes discusses the basics of DNA

Professor Sykes:
You all look a bit like your parents and the reason for that is that you've got from them something called DNA and DNA is an amazing code really, it's a biological code and it basically tells your cells and your body what to do, so it's the instructions really to building and running the human body.

And it's not just confined to humans, it's also in every other living form - plants, animals, birds, insects, everything. And it's made up of, like most codes, a series of letters so it's just like, you can think of it as a word really, and these letters are arranged in specific orders and just like any other word it's the order of the letters that counts.

So that's what spelling is and in DNA the sequence of the letters - the DNA sequence - is what's important and what these sequences do, these codes, they actually tell cells how to make proteins.