Phosphodiester Bond in Nucleic Acid Molecule

Nucleotides combine to form a phosphodiester bond. Binding occurs between the phosphate group at the 5th carbon of the pentose of the first nucleotide and the hydroxyl group on the 3rd carbon of the pentose of the second nucleotide. Both DNA and RNA are made up of a large number of nucleotides in succession. On one end of the DNA (or RNA) is the hydroxyl group -OH pentose (3 'end). On the other end of the DNA (or RNA), the phosphate group is from the phosphoric acid residue (5 'end). On the surface, NA is very negatively charged.