00:01
Well, i told that for dna has a radius of about 10.
00:06
It's a helix, of course, as we all know now.
00:10
Actually, that wasn't surprisingly not recently that that was discovered, actually.
00:17
So each helix has a radius of about 10 angstrom.
00:20
So i wrote, we're going to have a helix, the form of a helix.
00:25
And so we need this to be 10 angstrom.
00:28
And now i just use t here, just because this is my parameterization as we go around the helix.
00:38
And so i said, well, let's just say, because they tell us how much it rises in one turn.
00:45
And they tell us this, that's 34 angstrom.
00:48
So let's say, t goes from zero to one is one turn.
00:52
So that means we need two pi here.
00:54
So to go around once, as t goes from 0 to 1, we need 2 pi t.
01:02
And so then after one turn, we're at a distance from the start of 34 angstrom.
01:09
So they ask us for what is, if there's 2 .9 times 10 of the 8th turns, how long is the length of the molecule? or the backbone.
01:25
I think that's what they want...