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

[Borries Demeler]

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