[Spring2019] [ariel.frederick at umconnect.umt.edu: Question for BCH 581 - Ariel Frederick]

[Borries Demeler]

If anyone already finished the homework with this problem using my
incorrect formula there will not be any points taken off, as long as you
come up with a reasonable argument about what this result suggests.
You are allowed to fix it if you want, but your argument is very good
so that is acceptable as is.

Again, sorry about my typo in the handout, I should have been more
careful about checking my slides for accuracy.

-Borries


On Mon, Mar 04, 2019 at 05:01:49PM -0700, Vos, Timothy wrote:
> Hi Borries,
> 
> I just got your email about Ariel's question. I submitted my homework
> assuming a mw of 1.48 MDa. Is this going to be a problem? I tried to
> rationalize it as the chromatin wasn't forming even though the DNA alone is
> about 1.6 MDa. I'm more than willing to fix it if I'm allowed.
> 
> Thanks,
> 
> Timothy Vos
> 
> On Mon, Mar 4, 2019, 4:54 PM Borries Demeler <demeler at gmail.com> wrote:
> 
> >
> >
> > Date: Mon, 4 Mar 2019 23:02:13 +0000
> > From: "Frederick, Ariel" <ariel.frederick at umconnect.umt.edu>
> > To: Borries Demeler <demeler at gmail.com>
> > Subject: Question for BCH 581 - Ariel Frederick
> >
> > Hi Dr. Demeler,
> >
> > I know you said not to email you questions on the last day (did you mean
> > tomorrow?), so if you don't get back to me before the homework is due
> > that's fine. For the last question in part 3 where we are calculating the
> > apparent molecular weight of the complex between the DNA and the histones,
> > the molecular weight that I got is 1476.02 kDa, which is less than the
> > molecular weight of the DNA strand (660 Da per base pair x 2500 base pairs)
> > = 1650 kDa. I'm wondering how this is even possible. Any insights?
> >
> > Thanks,
> >
> > Ariel Frederick
> >
> > *********************************************************************************************
> >
> > Hi Ariel,
> > Holy smokes! That tells you once you become a professor you should do
> > the homework you assign yourself first! Yes, you found a mistake, the
> > problem is
> > with the equilibrium equation, there is a typo: it is missing a factor of
> > 2 in the
> > denominator, I forgot to put that in!!
> >
> > The correct equation for the slope should be:
> >
> > [M*w^2*(1-vbar*rho)]/[2*R*T]
> >
> > SO SORRY!! There will be extra credit for finding this mistake!
> > I will update the lecture slides and repost.
> >
> > -Borries
> >
> >
> > _______________________________________________
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> > Spring2019 at biophysics.uleth.ca
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> >