We were very disappointed this year to find that Blades have taken the traditional blood typing kits out of their catalogue. You can still get the Eldon card kits, but these are shockingly more expensive, much less fun, much more fiddly, and, we find, less reliable.
So we rang up Blades. Good news – they can still supply the original antibodies! Hurrah! Bad news – they took them from their catalogue because there was so little demand.
I was pretty depressed by this. As I’ve said before, it’s hard to think of a practical activity that is so immediately engaging, exciting and directly relevant to the students, whilst simultaneously covering so many interesting areas of A-level Biology.
Sure, blood typing itself isn’t on the syllabus. And sure, some people remain nervous about students taking their own blood – despite it being far safer than a blood injury in, say, rugby or hockey (or jabbing yourself with a needle in Textiles, for that matter).
Here’s how I use the blood typing protocol on our A-level taster day for Years 10/11 (though it would work equally well as an introduction to A-level at the start of the course).
Big SEM picture of red blood cells.
What are these then? What do you know about them?
Usual GCSE stuff on shape, function, flexibility, lack of nucleus and so on.
What do you know about blood types?
Quite a bit, it turns out, though generally a little confused. They’ve all heard of A and B and O and positive/negative, though they have no idea what this means. They have some vague idea that it’s important for blood transfusions.
Return to the picture of blood cells.
But how can blood be different? This is what your red blood cells look like. All of you.
Now for an Atomic Force Microscope image of a cell membrane.
Lots of suggestions as to what this looks like. Mountain ranges, craggy hills, and so on. But it’s a membrane.
That’s a bit more interesting that GCSE, isn’t it? What’s going on here? And, actually, if you’ve any curiosity at all, how could that GCSE fried egg drawing of a cell ever account for something as gloriously complicated as yourself?
I really like to stress the idea that at A-level, we start to find out what cells and their membranes are really like. It’s about trying to get that imaginative hook in place.
Very quick idea that craggy mountain tops are actually proteins. So you thought proteins were just something you needed to grow. And maybe, if you’re brain is on, for enzymes and digestion. But they’re FAR more interesting than that! There are zillions just in your cell membranes. Doing loads of jobs. And some of the proteins on the membranes of your red blood cells determine your blood group.
Cartoon of proteins of ABO group.
Stress idea that A-level Biology is basically jigsaws. If they like jigsaws, if they understand jigsaws, they’re half way there.
So how could someone be AB? They immediately see it. Their red blood cells have both proteins.
How could someone be O? There isn’t an O protein. Slight pause, and, again, they get it. Their red blood cells have neither protein.
Quick mention of positive vs negative. Maybe show a clip from the Tony Hancock blood donor sketch. Just a different protein. Same idea.
OK, why do you have that particular blood group? Where did you get your blood group from?
No problems with identifying their parents as the culprits.
But your parents don’t give you proteins. They don’t give you red blood cells, for that matter. What do they give you?
Thankfully, they’ve all heard of genes.
So what’s the link? Hopefully, Year 11s/starter Year 12s should be able to recall the genes code for proteins. Year 10s need the idea introduced, but quickly absorb it. Follow this with an outline of the different alleles and the possible combinations to be A, B, AB or O.
At which point they’re nicely primed to find out their own blood group. Again, this blog post outlines how they take their blood.
Great excitement etc etc.
Lots of things you can do once the results are in. Collate the class data. Compare it to the distribution in the UK. The brighter ones are now starting to ask questions about why do we have different blood groups. Maybe compare the UK distribution with a more Mediterranean distribution. What’s going on here? The idea that allele frequency can vary from place to place. How could they explain that? One more thing that we return to later in the course…
It’s also quite fun to pair two students up and ask them to work out how many of the other students could conceivably be their children, based on blood group inheritance. Time to throw in the Charlie Chaplin paternity case.
What do they make of that? General outrage at the scientific ignorance of juries.
But how does it work? Again, brighter students will have already asked this. How do the little circles (on the Eldon cards) “know” that blood contains A or B proteins?
OK, what can they see? What might those little red speckles actually be? Lots of suggestions, but eventually someone gets the idea that the red blood cells are clumping together. Right! Agglutination! Quick slide of anti-A/B antibodies.
Why is this important?
And you’re right into the blood typing game. Ask for volunteers to do this. Encourage them to try and take blood from the nose. Make sure the volume is turned up high. They “get it” impressively quickly. And can see that while being O is great for donating, it’s not so great for receiving. And the other way around for AB.
And to wrap up?
I always finish with the Ann Boleyn hypothesis. Was she Rhesus negative? Does that explain her first healthy child, Elizabeth, born to a Rhesus positive Henry? And all the subsequent miscarriages, as her immune system, primed to make Rhesus antibodies, attacks the foreign blood cells? Maybe! I reassure the girls who are Rhesus negative that this will not be a problem when the start their own family.
OK, OK, blood groups themselves are not on the syllabus. But even if you’re not convinced by the possibilities described above, there were the new OCR Breadth and Depth in Biology AS papers to remind us that:
- A-levels are going to be more difficult and
- students will be expected to apply their understanding in unfamiliar contexts.
I recall a training day some time ago where a teacher/Chief Examiner urged us to provide notes that were basically bullet pointed summaries of the learning outcomes, and to teach by filling in past papers with the mark scheme. When I asked him how this helped his students deal with synoptic questions, he was rather evasive.
I know that lots of teachers and students like this kind of approach. Indeed, many teachers at the CPD sessions I run will say something along the lines of, “Well, yes, that was fun, but my students just want to be given notes on what will come up in the exam.”
Except that training students on past papers and markschemes will only ever succeed in:
a) boring them
b) making them very good at answering past papers.
You’re then hoping that the exam board will just lazily re-use those same questions. Hence the outcry on the student room discussion boards when OCR has the effrontery to set a question that requires them to think and to show that they actually understand the Biology they’ve been taught. Sign that Facebook petition! We don’t have notes on: a traditional English Folk song The Derby Ram/icefish/N-acetylglucosamine/Amanita citrina (INSERT favourite example here).
Come on, let’s get Blades to put those blood typing kits back in their catalogue. And let’s aim to inspire and excite our students, rather than turning them into spoon fed mark scheme regurgitation monkeys….