Monthly Archives: October 2017

Russian roulette…

Just a quickie this week….

It’s Year 10 and the grim effects of smoking. The biology is interesting, though I must admit I prefer to celebrate the power of data to do good things (Richard Doll) and get them thinking about experimental design (how to show a causal link between smoking and cancer?). The following exercise is designed to cover these learning outcomes and doesn’t need much comment from me (though do look at the wonderful quote from James 1st/6th!).

Smoking and Epidemiology and Richard Doll November 2017

But how to convey the sense of genetic Russian roulette that is random mutation?

For this, I came up with the following interactive Powerpoint…

Random mutations in DNA interactive

The first slide just introduces chromosomes and we have a very basic chat about genetics and the idea of coded information.

chromosomes

A mutation, I explain, is just a random change to that information – the key point is, it could occur anywhere….

The second slide indicates 22 loci (the blue circles).

chromosomes 2

I ask a student to pick a blue circle, a locus. Any one they like. Clicking on the blue circle will, 21 times out of 23, take them to a slide saying:

Silent mutation

No effect no person

Clicking on the smiley face takes them back to the second slide, and the locus they selected magically disappears. We talk about the idea of silent mutations. Another student picks another circle, with, one hopes, the same effect.

But at some point, somebody will choose the bottom circle of the two on chromosome 7. Clicking on this circle takes them to this message:

Mutation to onco-gene

Uncontrolled cell division

Tumour

So I hope they take home the idea of random mutations and that smoking is like playing Russian roulette with your genes, but also the idea that the more you smoke, the more you increase that risk.

Short and sweet – let me know what you think!

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Festive Viral Fun

So, what kind of teacher are you?

When Year 11 start Infectious Disease, I always get them to build Jolly Christmas Viruses. There’s quite a variety of cut and stick models easily accessible on-line…

virus model

…and if you photocopy them on to lots of different coloured card and lay in industrial supplies of glue and glitter and pipe-cleaners, you can’t really go wrong.

I do insist that every virus be different. I show them a clip from Secret Life of the Cell (about 15 minutes in) where we see an adeno-virus gain access to the cell using its antigen and a cell receptor (this kind of hinting at the glorious complexity of A-level Biology is all part of my retention and recruitment plan).

And then I put on some salsa music and let them get on with it for an hour…

When they’re done, they attach a bit of cotton thread and we dangle them from the lab ceiling, where they quietly drizzle glitter on innocent students for the rest of the year…

IMG_2241

Here’s a not-particularly-special bacteriophage in mid-dangle.

I’ve worked with teachers who utterly fail to see the point of this lesson. It addresses no learning outcomes, it delivers no information, it utterly fails to tick a single learning objective on the specification, it uses up valuable Copy The Notes From The Powerpoint time…. I think they panic because they feel out of control – the students are working autonomously, and this is an uncomfortable feeling if you’re not used to it.

But…

It’s fun.

It’s different.

It’s memorable.

They will do wonderful things – one student produced a virus with a little portrait of Justin Bieber at the end of each antigen – the virus that causes Bieber Fever….

It gets them asking all kinds of interesting and relevant questions.

Because how can something so tiny (a virus to a football is the same as a football to the planet Earth…) and so simple (bad news wrapped in protein) make you ill? Discussion of rabies and smallpox and herpes and AIDS all follow naturally.

Which leads nicely to Immunology. Try my simplified animated Powerpoint as an introduction to Clonal Selection and Expansion…

Immune response

 

Blow their minds…

Sometimes you just have to amaze them. Go in and say, “have you seen the news today???? They’ve only gone and detected gravitational waves from the collision of two neutron stars!!!! Isn’t that amazing???? What? Neutron stars? Oh, stars that collapsed but didn’t quite become black holes. All the space in atoms crushed down so that a teaspoon of star has the same mass as all of humanity…. And two of them collided! Caused a kilo-nova! Equivalent of 1000 supernovas!!!!! Isn’t that mindblowing?!?!?!? And that’s where all the gold and platinum in the universe is made!!!!! So my wedding ring is made from stuff formed by two colliding neutron stars!!!!”

Of course, being biological burblings, I prefer, where possible, to use biological examples.

Such as some of the experiments emerging from epidemiology.

Heard the one about the mouse?

Conditioned with cherry blossom and electric shocks (almost sounds like a treatment for hair – wonder if it would help it re-grow?). So it learns to associate the smell of cherry blossom with an electric shock, and starts trembling with fear just with the smell of the blossom. Pure Pavlov.

But then let it breed – a nice break from electric shock therapy. And then expose the offspring to the scent of cherry blossom….

The offspring tremble with fear even though they have a)never been exposed to cherry blossom before and b)never had an electric shock in their lives.

That’s incredible. How does it work? We don’t know! But that’s where and why science is exciting, pushing at the frontiers of knowledge and trying to understand the universe better.

Heard the one about the other mouse?

Stick it in a cage with a bigger mouse where there’s nowhere to hide. The smaller mouse gets bullied. Becomes fearful and runty. Doesn’t grow. Stressed and pathetic.

But then pop it in a cage with a female and let it breed. Again, makes a nice change for it.

The offspring are all fearful, runty, stunted, stressed pathetic mice.

Seems like more evidence of epigenetic effects.

BUT!!!! – now you can talk about the importance of experimental design and rigorous controls.

Repeat the experiment, but instead of letting the bullied mouse breed, extract its sperm (don’t ask how) and artificially inseminate the female.

Guess what – when not exposed to Mr Runty himself, the offspring are all perfectly normal. So not epigenetic, but still pretty bloody amazing – the female can somehow adjust her level of maternal investment based on the apparent quality of the male.

How??????

I think this kind of thing is so important. Because if you can’t get excited about your subject, why on earth should you expect your students to? And keeping up to date with the latest developments provides a constant supply of amazing stories to inspire them with.

Role-playing Homeostasis

As regular burble fans will know, I use lots of role play in my lessons. Students become molecules, baboons, ship-wrecked survivors, blood-letting physicians and so on. In this lesson, which covers the whole of the Homeostasis topic, they have a wide variety of roles. With a synoptic set of homework questions to follow. Note the props!

The downloadable script is here: Homeostasis Play anonymous version October 2017

(note that you can choose the name of a specific student by using Word replace function to replace Student with a name...)

but for ease of reading, I’ve also included it below.

Student’s Big Day Out

an adventure in the Homeostatic Wonderland of Student’s body

Dramatis personae

  • Student’s brain
  • Student’s liver
  • Student’s pancreas
  • A sweat gland in Student’s skin
  • Student’s kidneys
  • Glucose molecules
  • Insulin
  • ADH
  • Student’s muscles
  • An Enzyme
  • Student
  • Student’s teacher
  • Heart and Lungs

Props

  • Model: heart, lungs, brain, liver, kidney
  • Large beaker – red water
  • Large beaker – yellow water
  • 3 x distilled water bottles
  • Can of Coke
  • Potato
  • Thermometer
  • Torch
  • Weights

Student

You join us at an exciting point in my school day. I’m about to walk down the corridor to my favourite lesson of the week, Biology. Can my body cope with the extraordinary demands that this exercise will present? Or will I die? Let’s find out.

Student’s muscles (pumping iron)

Typical. We do nothing all day long and suddenly we have to work really hard. Contract, relax, contract, relax, contract, relax. Where’s the oxygen? Where’s the glucose? It’s not easy being a muscle, I can tell you, especially Student’s muscle. Phew, it’s getting a bit hot in here…

Enzyme

(very camp) Tell me about it! Here I am, controlling the rate of respiration, producing ATP, basically helping this boy/girl here do her work, and it’s warming up. Doesn’t he/she know I might denature? Just look at my active site! (displays active site) Very sensitive, me. What will he/she do without respiration? I’m the main character in this play, and don’t you forget it.

Brain

(yawns). Hmmmm? Whassup? Whassgoingon? Oh, right, it’s the end of Maths. Mmm,  and now I seem to have made a decision to walk along a corridor. Better check on the blood temperature. (dips thermometer into blood). Blimey! It’s gone up 0.1˚C! Time for a bit of action on the cooling front. Ermmm, what do I do? Errm, damn, if only I’d been paying attention in that fantastic Biology lesson, I’d know the answer. Help! It’s gone up 0.2˚C! This could get critical. What do I do?

Enzyme

I’m OK for the moment, but don’t push your luck. 0.2˚C I ask you.

Liver

Send an impulse!

Brain

What?

Liver

Send an impulse! Cor, call yourself a brain? I’ve seen bigger brains in an intestinal nematode. No question who the most important organ round here is.

Brain

I agree. No question at all. Look at how complex I am. Look at all the things I control and monitor. I’m responsible for all his emotions and memory and everything! Definitely THE most important organ.

Liver

Pah, if I wasn’t here to store the glycogen, heat the blood and break down toxins, you wouldn’t last 5 minutes. I’m the centre of metabolic activity, me, so less of the superiority complex. Every animal has a liver. Very few have a big brain. Check out any Year 8 student.

Brain

So what?

Liver

Well, put it this way. If I wasn’t around to break down the alcohol in people’s bloodstream on a Friday night, they would be terminally dead before Saturday morning. Anyway, stop prevaricating and send a flaming impulse! We’re all getting warm down here.

Brain

But an impulse to where?

Liver

A sweat gland, you great wally!

Brain

Oh yeah, a sweat gland. (shines torch at sweat gland).

Sweat Gland

An impulse! Hurrah! Let’s get sweaty! (squirts water over Student). Lucky I’m here. All this water will evaporate off his/her skin and he/she will lose heat as a result. How cool is that?!?! (continues to squirt Student)

Enzyme (grudgingly)
Hmmm. Things do seem to be cooling down a bit. That’s nice. But hey, not too much cooling! I’m very sensitive, me.

Liver

As she keeps saying. Hope that stupid brain is on the job. We seem to be losing a lot of water.

Brain

(snores)

Kidney

Oi! Brain! Wake up!!!!

Brain

Huh? What now? Honestly, if it’s not one thing it’s another.

Liver

(sarcastically) Notice anything?

Brain

(defensively). Er, no. (looks at thermometer). Er, yes! We’re back to ideal blood temperature! Hurrah for me!

Kidneys

Notice anything else?

Brain

What do you take me for? A biologist? Though now you mention it, this blood seems a bit sticky.

Liver

Ta da! Come on, get your osmotic pressure sensor out!

Brain

(guilty) Oops! (dips potato in blood and looks at it) Oh no! Now we’re losing water too fast! (looks at thermometer). But we’re still heating up! (shines torch at sweat gland who squirts Student)

Sweat gland

Still sweating! No sweat, sir.

Brain

But we need sweat!

Sweat gland

That’s what I mean! It’s no sweat to keep sweating.

Brain

Oh, right. (looks at potato). But the blood is getting too concentrated! If the blood gets too concentrated, something horrible will happen. And if I had only done the theory on the Osmosis project back in Year 9, I’d know what!  Help! What do I do now?!?!?

ADH

(very French: coughs meaningfully)

Brain

Who are you?

ADH

Who am I? who am I? I am zee famous ADH, that’s who. Antee, Die-yoo-rettic Hormone.

Brain

So?

ADH

Releasez moi!

Brain

What?

ADH

Releasez moi!

Brain

But I’m not holding onto you!

ADH

Look, you English fool, your father is an ‘amster and your mother smells of elderberries. I shall say zis only once. Send an impulse to zee pituitary gland which is just in front of you. And it will release me into ze bloodstream. Do it! Before your little cells shrivel up and make you even less capable of rational thought than you already are, and I shall taunt you once again!

Brain

OK OK OK, here goes. (shines torch at ADH)

ADH

Close enough! I am free! (floats along in the blood stream knocks on liver) Allo? Is zis de Kidney?

Liver

No, I’m the Liver. Go away!

ADH

Ooops, sorry, I shall try again. (bumps into Pancreas). Allo? Are YOU ze Kidney?

Pancreas

Oh go away. My receptors do not match yours.

ADH

Let’s try again. ( bumps into Kidney) Oi, Kidney!

Kidney

(cheerfully squirting water into the bladder)

What?

ADH

Stop excreting water!

Kidney

Why?

ADH

Coz I tell you to, you dozy organ. We’re losing too much water in the sweat and at this rate he/she’ll be dead from dehydration. Stop excreting water!

Kidney

  1. (stops squirting water)

(pause)

Kidney

Is that it?

ADH

I’m afraid so.

Kidney (grumbles)

Very small part for me.

Muscle

Oxygen! Give me more oxygen! And get rid of this damn carbon dioxide!!!!

Brain

(shines torch at Heart and Lungs). Come on, chaps! Work harder!

Heart and Lungs

We canna give her any more, cap’n!

Muscle

Phew! We’ve stopped! He/She must have reached the classroom.

Heart and Lungs

Thank heavens for that!

Brain

(shines torch at Heart and Lungs)

Calm down, sort out the oxygen debt, and then return to resting levels. Right, I’m thirsty.

ADH

Of course you are. That’s something else I do.

Brain

Hmm? Is the teacher watching? Quick! Let’s drink some coke! (Student swigs some Coke).

Teacher

(thunders) Student’s surname!! Are you mad! You are deliberately imbibing the drink of the devil! You will suffer tooth rot, mood swings, caffeine addiction and Type 2 diabetes! Put it away this instant!

Student

(meekly) Yes sir. Sorry sir.

Brain

(shines torch at sweat gland) You can stop too.

Sweat gland

No sweat no sweat!

Brain

Er, yes.

Pancreas

Never mind the sweat! It’s too late! The stomach is full of glucose molecules and we’re going to have big problems here very, very soon!

Liver

Yes, everyone knows that you only have a teaspoon of glucose in your blood at any moment. Student’s just drunk something that’s 30 times more concentrated! What’s going to happen?!?!? (picks on non-actor to answer the question).

Pancreas

Exactly! Luckily, I know what to do. Insulin!

Insulin

(salutes) Insulin reporting for duty sir!

Pancreas

Ah, Insulin, loyal and trusty hormone. You must hurry to the Liver. Travel in the bloodstream. You know what you must do.

Insulin

(salutes) Yes sir! (hurries off in bloodstream, passing Glucose molecules that are entering from intestine). Cor, look at all this glucose! If this gets much worse, the blood will get too concentrated, and Student will lapse into a coma. Would anyone notice? Hmmmm. But we must still avert the danger! Watch me go!

(reaches Kidney)

Oi, Liver!

Kidney

I’m the kidney! Sort out your receptors!

Insulin

Ooops, sorry. I’ll try again. (reaches Liver) Oi, Liver!

Liver

Oh, look, a little hormone. What can I do for you, little hormone?

Insulin

Less of the patronising nonsense, sunshine. You’ve got a job. See all this glucose?

Liver

Yes.

Insulin

Get it out of the blood! Take it into your cells and do something with it. But do it quickly!

Liver

Righty ho. (starts grabbing glucose). In you come, all of you, that’s it, through the membrane, out of the blood. Naughty glucose! See the problem that brain causes? If it hadn’t decided to drink that Coke, none of this would have happened!

Brain

Don’t you start again.

Liver

Oh don’t mind me. I’m just a liver. You’re the suicidal idiot who dumps all this rubbish on the body. I’m just the poor sap who has to deal with it. (sotto voce) She’d have been much better as a gut nematode. (louder). Right, you glucose molecules, line up! Attention! I’m going to put you into storage. But I can’t store you as glucose because you’ll affect my osmotic balance. Here, link arms. (glucose molecules link arms). Good! Now you’re a molecule of glycogen, and you can stay there until we need you.

Enzyme

What happened to the cooling mechanism? It’s still too hot.

Liver

Must be the school’s lack of air conditioning. Get the brain to sort it. Brain! Oh brain!

Brain

(snores)

Kidney

Oh great. He’s dozed off. What shall we do now?

Enzyme

Wake up! We’re overheating!

Sweat gland

Can’t do anything without a signal from the brain

Muscle

Wake up!

Liver

(smugly) I said this would happen.

Enzyme

I’m melting!!!!! (active site changes shape)

Muscle

Help! If he can’t work, the body can’t respire!  Check out the 7 life processes!

Kidney

Ermm, movement? growth? ermmm, beer?

Muscle

RESPIRATION, you dolt! All LIVING things respire. And we’ve stopped respiring!!!

Liver

Bother. There goes respiration. We’re going to die!!!!!

 

THE END