The zipper model is a cooperative model for helix-coil transitions. Here we demonstrate an important feature of this model, i.e. that once helix become energetically favored over coil, long runs of helix are favored over shorter runs.

For N=30, s=1.5 and ?=0.001 calculate the partition function q/q0 .
=1714
Calculate the probability that a peptide for which N=30 has a helical length of k=20. Assume s=1.5 and ?=0.001