Hairpin formation and elongation of biomolecules

We introduce a model of thermalized conformations in space of RNA - or sing le stranded DNA - molecules, which includes the possibility of hairpin form ation. This model contains the usual secondary structure information, but e xtends it to the study of one element of the ternary structure. namely the end-to-end distance. The computed force-elongation characteristics are in g ood agreement with sonic recent measurements on single stranded DNA molecul es.