Which description applies to the DNA backbone?

Which description applies to the DNA backbone?

• A. A chain of amino acids
• B. A network of lipids
• C. A sequence of base pairs
• D. A repeating pattern of sugar-phosphate-sugar-phosphate

Answer: (D)

The backbone describes the repeating sugar-phosphate framework that runs along the edges of the DNA molecule. It is made up of deoxyribose sugars linked by phosphodiester bonds to phosphate groups, forming a continuous sugar-phosphate-sugar-phosphate pattern. The bases sit tucked inside as the rungs of the ladder, carrying the genetic information through their sequence. So, describing the backbone as a repeating sugar-phosphate pattern fits DNA’s structural role, while the other options refer to proteins, membranes, or the actual base-by-base code rather than the backbone itself.

The backbone describes the repeating sugar-phosphate framework that runs along the edges of the DNA molecule. It is made up of deoxyribose sugars linked by phosphodiester bonds to phosphate groups, forming a continuous sugar-phosphate-sugar-phosphate pattern. The bases sit tucked inside as the rungs of the ladder, carrying the genetic information through their sequence. So, describing the backbone as a repeating sugar-phosphate pattern fits DNA’s structural role, while the other options refer to proteins, membranes, or the actual base-by-base code rather than the backbone itself.