00:03
This is the answer to chapter 3, problem number 17, from the smith organic chemistry textbook.
00:11
And we're asked in this problem, why does aspirin cross a cell membrane as a neutral carboxylic acid rather than the charged ionic bound conjugate base? so basically, the answer is this.
00:33
So cell membrane is a phospholipid bilayer.
00:37
And so what that means is that there are polar head regions that i'm just going to abbreviate with peas.
00:52
And then each of these has a non -polar lipid tail.
01:06
Okay? and so this region is non -polar, as is this region.
01:18
And then the region of the blue peas here is the polar region.
01:25
So let's arbitrarily call this outside the cell.
01:31
And we'll call this inside the cell.
01:35
Okay.
01:36
And so aspirin, i'm going to just abbreviate as r.
01:44
Oh, so here is our uncharged carboxylic acid...