the 2 sides of the dna ladder are called what
Watson and Crick discovered that DNA had two sides, or strands, and that these strands were twisted together like a twisted ladder -- the double helix. The sides of the ladder comprise the sugar-phosphate portions of adjacent nucleotides bonded together.The phosphate of one nucleotide is covalently bound (a bond in which one or more pairs of electrons are shared by two atoms) to the sugar of the next nucleotide.ach nucleotide consists of a sugar (deoxyribose) bound on one side to a phosphate group and bound on the other side to a nitrogenous base. There are two classes of nitrogen bases called purines (double-ringed structures) and pyrimidines (single-ringed structures). The four bases in DNA's alphabet are: