BSCI 426/BIOL 622         Fall '14                             Problem Set 2

assigned:     9/11/14
due            9/18/14

Given that the interfacial force, gamma, for a phospholipid membrane is 5 x 10^-6 J/cm² and that the average surface area of a phospholipid molecule is 0.5 nm², calculate the value of "K" (molecular repulsion coefficient) by taking the optimal area as the area of the phospholipid molecule.

1. What is the minimal free energy per phospholipid molecule? (expressed as Joules per mole)

2. What area changes are reasonable at room temperature? Describe this in words and explain what are the appropriate considerations.

Optional (extra challenge)...actually replaces item 2

3. Determine the probability of achieving a particular phospholipid unit area (i.e. a particular area for one phospholipid). Plot this as a function of area.