Amino Acids R Us; plus SP10!
Well, it's been a busy week. I've been cramming in a lot of biology, which includes the organic and inorganic chemistry I never really understood the first time I touched it in the early 80's. Guess what? I get it! I get it!! Oh, I'm so excited. So simple! Carboxyl group, then that bonds to a carbon atom which bonds to a hydrogen and an amine group (which is either NH2 or NH3, depending it seems on what the notation convention being used is--you either stick the extra H on the carboxyl end and call it COOH or the amine end, and either write the charge or not), and then--ah!--then the last bonding site for the carbon that's in the middle gets one of the R thingies. And you can keep on sticking these molecules together in really long chains willy-nilly, and then they scrunch up on themselves and that's determined by the interactions between the R pieces. So cool! Ha ha! Biochemistry joke in the heading, there. Did I mention that I'm excited? Well, I am. And the particular type of sequence in the protein determines how it reacts to the ions inside and outside the cell wall and whether it will let in (or out) the potassium, sodium, chloride, or calcium--and there are only those four options, actually.
Did I mention I was excited? I was wondering, hm, if you could figure out the exact structure of those protein gates, that'd be pretty darn interesting. So according to my textbook, the structure of the potassium gate is now known and was such a huge deal to figure out that, um, that was the 2003 Nobel prize. (the diagram is pretty fun and slightly unintentionally funny, because it's very pretty and helpfully says, "the red ball in the middle represents the potassium." well, duh, it's a potassium gate. Snort.) So maybe not so simple trying to actually figure out the actual conformation of the molecule; perhaps not even the precise amino sequence. Details, details.
I completely owe my grasp of this to the astonishingly clear explanations in the Thinkwell biology course. Both my kids are working through this, too; which means they know it as well as I do, probably more so. Which is pretty cool. If you click on the link and look at biology, you'll see the stupendous sample lecture on functional side groups. Very exciting stuff.
So I've done the reading for the first class meeting of my neurobiology course, also for the second class meeting. First class: all of neuroanatomy. Gulp. Good thing I checked ahead of time and started early, eh? I've got it down pretty well, as long as I'm looking at a neat tidy drawing in a book. The class handout has photos of actual brains, though, and they're covered with blood vessels and I can't quite even identify the central sulcus from there, fer cryin' out loud. Amazing how the cranial nerves are sooo easy in a drawing, and then since I know them in relationship to each other, if I can't see one of them in the photo of the actual brain, I'm basically screwed. Well, except for the first optic nerve. 'Cause it's in a totally different part of the ventral side of the whole structure. Oh, and I keep forgetting the name of the cortical stuff you can see underneath when you pull apart the Sylvian fissure.
Anyway, reading for the Wed. class is--ta da!--the biochemistry I just finally "got" over the weekend, plus a few extra bits. The Nernst equation, for example. Which gives you the equilibrium potential of the ion--basically the voltage (no chemistry pun intended, ha ha "base," ha ha). I think. It's 2.303 times the temperature (body temperture, usually, in C) divided by the charge (yes, dividing by plus one, plus two, or minus one--this is not rocket science) (but it is neuroscience, mwa ha ha), then multiply that by the log of the ratio of the concentration of the ion outside the cell to the conc. inside. Ta da. Easy-peasy. I do not get where the 2.303 comes from, or why you can just disregard the Faraday constant and the gas constant but somehow have to use the (apparently Nernst constant?) 2.303. But the calculation itself is really simple.
Okay, I probably lost most of you a paragraph or so back. Yay, action potential! (yes, Suzanne, yay!) Yay, neuroscience! Yay!
I couldn't think of a way to combine the oh-so-exciting neurobiology with my Secret Pal parcel, so ... you get an inelegant post today. Ah, well.
I got my final Secret Pal parcel! It is *amazing*! I'm so thrilled, and touched, and thank you so much, Ruth! Pic:
I posted a while back that I'd really wanted to make the Peace Shawl rather than the Charlotte's Web that I started, and she's sent me the pattern for the Peace Shawl! Amazing! Thank you so much. Plus three skeins of laceweight... malabrigo. (swoon, thud) (just once, could I not faint? apparently not.) It's green, and lovely, and there's some way fun doodads and some awesome chocolate. Gasp. So wonderful. Thank you so much, Ruth. (this is not this Ruth; she's a different Ruth. Just in case you're confused.) (hi, Ruth!)
'Bye from Geekland, all; see you soon.