Covalent linkage in nucleic acid backbones
Connects sugar and phosphate groups
A phosphodiester bond links nucleotides in DNA and RNA by connecting the phosphate group of one nucleotide to the sugar of the next. This creates a sugar-phosphate backbone with directionality from the 5' end to the 3' end. New nucleotides are added to the free 3' hydroxyl group during nucleic acid synthesis.