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Homework Help: Estimating entropy in DNA packing

  1. Dec 8, 2009 #1
    1. The problem statement, all variables and given/known data
    Estimate total work that motor [tex]\phi[/tex]29 needs to perform to overcome entropy loss of packing DNA

    2. Relevant equations

    P(R,N)=(3/2[tex]\pi[/tex]Na[tex]^{2}[/tex])[tex]^{3/2}[/tex]e[tex]^{(-3R^{2})/(2Na^{2}}[/tex])
    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[tex]\approx[/tex]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
     
  2. jcsd
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