Final answer:
The 5'-3' linkage of nucleotides in nucleic acids is formed through phosphodiester bonds, which are covalent bonds necessary for the creation of the sugar-phosphate backbone in DNA and RNA strands.
Step-by-step explanation:
The 5'-3' linkage of nucleotides in nucleic acids occurs through phosphodiester bonds. These covalent bonds are formed by a dehydration synthesis reaction where a hydroxyl group is removed from the 3' carbon of one nucleotide and a hydrogen is removed from the 5' carbon of another nucleotide. This reaction results in the release of water and the formation of a phosphodiester bond that links the sugars of the two nucleotides, contributing to the backbone of nucleic acid strands like DNA and RNA. Individual nucleotides are assembled into a polymer where each nucleotide is connected by these bonds, with a free phosphate group at the 5' end and a free hydroxyl group at the 3' end of the growing chain.