# Estimating entropy in DNA packing

1. Dec 8, 2009

### emoboya3

1. The problem statement, all variables and given/known data
Estimate total work that motor $$\phi$$29 needs to perform to overcome entropy loss of packing DNA

2. Relevant equations

P(R,N)=(3/2$$\pi$$Na$$^{2}$$)$$^{3/2}$$e$$^{(-3R^{2})/(2Na^{2}}$$)
This equation gives the end to end distribution or a 3D random walk with N segments length a.

3. The attempt at a solution
I'm not 100% sure where to start on this. I've been trying to figure it out all day, honestly. I know that DNA has a persistence length a$$\approx$$100nm because it's fairly rigid over about 300 base pairs. It is therefore modeled as N=65 segments.
I'm not sure where to go from here though. How do I come up with the entropy change by putting the DNA in the capsule?

I planned to model the capsule as a sphere of radius 20nm. Any help on where to go from here?

Thanks