  We investigate the stretching response of a thick polymer model by means of
extensive stochastic simulations. The computational results are synthesized in
an analytic expression that characterizes how the force versus elongation curve
depends on the polymer structural parameters: its thickness and granularity
(spacing of the monomers). The expression is used to analyze experimental data
for the stretching of various different types of biopolymers: polypeptides,
polysaccharides and nucleic acids. Besides recovering elastic parameters (such
as the persistence length) that are consistent with those obtained from
standard entropic models, the approach allows to extract viable estimates for
the polymers diameter and granularity. This shows that the basic structural
polymer features have such a profound impact on the elastic behaviour that they
can be recovered with the sole input of stretching measurements.
