Friday, August 31, 2012

Recombinant DNsnAkes

DNA Snakes.

Last week I had a dream about using snakes to model DNA, and made a plea to Jon to let me buy Yet More Stuffed Animals.

Then, during a grammar lesson about direct and indirect objects, Eric modified a boring sentence into  a silly one: "I threw Sally at the purse." Eyes a-twinkle, he added "Though why on Earth I would want to throw someone named Sally at a purse..."

"Well, if we had a stuffed animal named Sally," I began, and then had a flash of inspiration. My whole family call these my Brilliant Ideas.

"We should get a stuffed rattlesnake!" I said. "And name her Sally. And then use her in my DNA lesson. And then throw her at my purse!"

Granted this only combined two disciplines. --Wait, I mentioned Watson, Crick, the Nobel Prize, and Rosalind Franklin. In passing, but we'll count it. Plus, during lunch, I told the story of baby Hercules "playing" with two lethal assassin snakes in his crib. And the story of The Snakes of Gettysburg. History. That's three! -- Next week we'll manage to integrate all four when I have Eric read a biography of Isaac Newton.

We had fun choosing the snakes. I was trying to keep it down to two, but somehow mission creep and a saleslady offering us a deal conspired to up the number. (But I was good and didn't buy the adorable baby deer! Did you hear that, honey?) As I considered which snakes to choose, I looked at them severely. "Now, no trying to crush baby Jeff," I told the python sternly, and he shook his head. Also "Absolutely no biting Sam if he steps on you!" I admonished the rattlesnake, who also shook his head in humble agreement.

Unofficially, Eric has adopted the python. (Too bad he already has an animal named Pythagoras.) Daniel grabbed the orange "corn snake" and dubbed her Sally. I let Jeff hold the rattlesnake on the way home because of it's baby toy properties. That left the "gopher snake" (most realistic-looking and -feeling) to Sam.

They played all the way home. With, sadly, a fair number of rude hisses. Plus biting and crushing.


Violence aside, today was awesome because Daniel got to participate. (He had a doctor's appointment in the middle of the day, after which there was little point in sending him back to school.)

It took a little while to get everything organized.

"No, no, boys. First we need to study normal double-helixed DNA.
THEN you can invent freaky mutant alien sssextuple-helixed tangles."

I used color-coded paperclips for the amino acids. Secured 'em to the snakes with matching rubber bands. Eric and Daniel helped to "bond" the matching bases...

 "Base Pairsss"

...and then twist them.

"Twisted Double Helixsss"

When it was time to replicate, they "unzipped" (see picture at top), then each took an original snake and a "negative" and raced to see who could get a complete strand first.


Daniel finished slightly ahead but I had helped him. We ruled it a tie.

The boys compressed their strands as much as possible and called them "chromosomes."


The lesson was vastly simplified and riddled with errors, some of which were even intentional.

We also touched on genetic errors--not my fault!--like mutations.


I think DNA works differently now than it did when I was in ninth grade. Or I received faulty teaching (unlikely) or I remember it incorrectly (um). The two sources I pulled off the shelf -- a high school biology textbook and The Way We Work were both excellent. Someday I'll actually read them thoroughly, and try this again, including minor details like messenger RNA. Once I understand what's going on, I can also invent a story about the snakes' struggles and motivations.

One more nice thing about homeschooling -- I can cram remedial biology at my own pace.

Maybe I'll start by borrowing The Cartoon Guide to Genetics from Eric. I got the feeling today that he knew twice as much as I did, and was merely humoring me. (I think it was when he said that he knew how RNA synthesized proteins but he didn't feel like explaining it to his parents.)

Up next: On Monday, I think the whole family will gather to watch highlights of the Republican National Convention. We'll count the number of stuffed animals thrown during each speech and come up with our own ranking of who are the most obnoxious politicians. In fairness, we'll do the same thing to the Democrats. It's like our own personal "Pinocchio" politics.

Speaking of hurling stuffed animals at inanimate objects, as soon as our formal activity was over, Daniel threw Sssally at my pursssse.


Jon said...

Maybe we should just throw the snakes at the politicians (Republicans or Democrats). Perhaps some of their (the politicians') DNA will rub off onto the snakes and make them more lifelike.

Jon said...

Cool idea for a homeschool lesson, BTW.