Number of phosphodiester bonds found in one turn of DNA is ________.

• A. 18
• B. 10
• C. 40
• D. 38

The number of phosphodiester bonds in one turn of DNA is a key aspect of its structure. Each turn of the DNA double helix consists of a specific number of nucleotides, and each nucleotide is connected by these bonds.

Understanding Phosphodiester Bonds

Phosphodiester bonds link the sugar and phosphate groups of adjacent nucleotides, forming the backbone of the DNA strand.

Calculating the Bonds

In one complete turn of the DNA helix, there are typically about 10 base pairs. Since each base pair is connected by a phosphodiester bond, and considering the structure of the double helix, the total number of bonds can be calculated.

• Each base pair contributes one bond.
• There are two strands in the helix.
• Thus, for 10 base pairs, there are 10 bonds connecting the bases.

However, to account for the complete structure, we also consider the bonds at the ends of the strands. Therefore, the total number of phosphodiester bonds in one turn of DNA is typically around 38.

Final Answer

The correct choice is D. 38.