Problem 3 (28 points). Let's consider the unfolding of a helix into a coil. Initially, we have a strand of N residues, in which each residue is helical: HHH...HHH . Unfolding starts when one of these helical (H) residues flips to a coil (C). This can happen either at a terminus of the strand (resulting in either CHH...HHH or HHH...HHC) or somewhere in the middle of the strand (for example, HHH...C...HHH). Let's use the Zimm-Bragg model to study this system. a (7 points). Argue that the unnormalized statistical weight for strands that started unfolding at a terminus equals 2as". b (7 points). Calculate the unnormalized statistical weight for strands that started unfolding somewhere in the middle of the strand (i.e. not at one of the termini). (7 points). The factor statistical weight of strands that start unfolding at a terminus ~ statistical weight of strands that start unfolding somewhere in the middle will be >1 if unfolding starts at a terminus, and