ABSTRACT
This chapter presents a brief description of the basic chemical properties of the biomolecules whose statistical physical properties. RNA structure is complex, but the number of the basic variable elements is only four, hence small when compared to the twenty amino acids of the proteins. DNA and RNA are charged polymers composed of three structural elements: a sugar, a phosphate group and the bases. DNA structure can vary between different conformational and topological states, but these are usually based on a double-stranded molecule. Like DNA, the molecular building elements form hydrogen bonds with each other to stabilize planar structures. The application of a magnetic field allows to pull on the bead and hence the DNA molecule. J. F. Marko and E. D. Siggia in 1994 proposed another continuum model for DNA elasticity which has enjoyed some recent interest also from the experimentalists; it is therefore briefly discussed at this point.
