Final answer:
In a phosphodiester bond, the phosphate group attached to the 5' carbon of one nucleotide's sugar forms an ester linkage with the hydroxyl group on the 3' carbon of the adjacent nucleotide's sugar.
Step-by-step explanation:
In a phosphodiester bond, the 5' carbon of the sugar molecule in one nucleotide is connected to the 3' carbon of the sugar molecule in the adjacent nucleotide. This bond is formed when a phosphate residue attached to the 5' carbon of one nucleotide's sugar forms an ester linkage with the hydroxyl group on the 3' carbon of the sugar of the next nucleotide. The formation of phosphodiester linkages is a key part of the polymerization of nucleotides into the nucleic acid strands of DNA and RNA, creating a sugar-phosphate backbone that is characteristic of these molecules.