Question

In a polynucleotide chain, nucleotides are linked together by which type of bond?

Options

• N-glycosidic bond

• Ionic bond

• 3′–5′ phosphodiester bond

• Hydrogen bond

Answer 1

Nucleotides are joined by a 3′–5′ phosphodiester bond, where the phosphate group at the 5′ carbon of one nucleotide forms an ester linkage with the 3′-OH group of the adjacent nucleotide. This repeated linkage creates the sugar-phosphate backbone of the polynucleotide chain.