Daily Archives: November 9, 2016

Random mutations

A few new ideas are starting to bubble to the surface – which is a relief, not quite burned out yet – though the main constraint on sharing them with anyone remains time. So it’s another quickie this week.

It’s Year 10. It’s gas exchange and smoking.

I like to start this topic by showing them a picture of Humphrey Bogart and Lauren Bacall.


Who are these? There are some wonderfully entertaining guesses, but no-one ever gets it right. Never mind. I then show a clip from The Big Sleep. Don’t worry too much about the plot or the dialogue – though notice the on-screen chemistry between the two – but what do you notice?

Yep, everyone is smoking. I talk about how smoking used to be allowed in pubs – going out for a drink when I was at university meant coming home with your clothes reeking of cigarette smoke. Just horrible. My mother can remember when you could smoke on the London Underground. Imagine that!

But why?

This leads into the rest of the slide show where I show these extraordinary adverts that see smoking promoted by dentists, doctors and babies. Look at the tag-lines – “throat protection.” It almost beggars belief. We discuss the effects of advertising, of peer pressure, of glamorous Hollywood stars. So why did it change?

Time for a bit of data interpretation, with a simplified version of Richard Doll’s data followed by getting them to design an experiment to test the link. This generally leads to heated arguments about whether we should experiment on humans or animals, but is great for thinking about controls and measurements and sample size. The pictures of the beagles and the mice are sobering for everyone.

But we also need to stay up to date. The recent publication of research showing the actual genetic effect of smoke on lung cells is extraordinary and fascinating, but how to make it accessible to Year 10s who haven’t covered DNA and have but the shakiest idea of what a gene might be.

Try this. random-mutations-in-dna-interactive

An interactive Powerpoint which introduces the chromosomes – brief introduction – and then has 20 or so locations on the chromosomes (disclaimer – these are not the precise location of specific genes!). The locations are hyperlinked. I hand the remote mouse to the students and tell them take it in turns to “smoke a cigarette” and thereby induce a mutation by clicking on a blue circle. All but one of these “mutations” will go to Slide 3 where there is no effect. But one of them hyperlinks to Slide 4, Onco-gene mutation and its consequences.

It conveys the idea that mutations are random, and that smoking is like Russian Roulette. You might dodge the bullet for a while, but sooner or later…

Let me know what you think. Ideas for improvement or adjustment particularly welcome.