Phosphodiester bonds in nucleic acids connect which components of neighboring nucleotides?

• A. The Sugar of One Nucleotide to the Phosphate of the Next
• B. The Phosphate to Another Phosphate
• C. The Sugar to Another Sugar
• D. The Base to the Sugar

Answer: (A)

The backbone of nucleic acids is built from sugar and phosphate linking together. A phosphodiester bond forms when a phosphate group from one nucleotide esterifies to the sugar of the neighboring nucleotide, effectively connecting the sugar of one unit to the phosphate of the next. This creates the continuous sugar–phosphate backbone that runs along the length of the strand, with the bases sticking out to pair with complementary strands.

Why this is the best description: the bond directly ties the sugar of one nucleotide to the phosphate of the next, not sugar-to-sugar, nor phosphate-to-phosphate, nor base-to-sugar within a single nucleotide. The result is a covalent linkage that forms the repeating sugar–phosphate chain essential for nucleotide connectivity.