The nucleic acid backbone is composed of alternating sugar and phosphate groups; which sugar is in DNA?

The nucleic acid backbone is composed of alternating sugar and phosphate groups; which sugar is in DNA?

• A. Ribose sugar and phosphate
• B. Deoxyribose sugar and phosphate
• C. Glucose and phosphate
• D. Deoxyribose sugar and sulfate

Answer: (D)

DNA’s backbone is a chain of alternating sugar and phosphate units. The sugar in DNA is deoxyribose, a five-carbon sugar that lacks an oxygen at the 2′ position compared with ribose. Phosphate groups link the sugars through phosphodiester bonds, connecting the 3′ carbon of one sugar to the 5′ carbon of the next. This creates the long, negatively charged backbone of DNA. In contrast, RNA uses ribose (with the 2′-OH) and glucose isn’t part of nucleic acid backbones, and sulfate isn’t involved in the backbone either. So, the sugar in DNA is deoxyribose, paired with phosphate to form the backbone.

DNA’s backbone is a chain of alternating sugar and phosphate units. The sugar in DNA is deoxyribose, a five-carbon sugar that lacks an oxygen at the 2′ position compared with ribose. Phosphate groups link the sugars through phosphodiester bonds, connecting the 3′ carbon of one sugar to the 5′ carbon of the next. This creates the long, negatively charged backbone of DNA. In contrast, RNA uses ribose (with the 2′-OH) and glucose isn’t part of nucleic acid backbones, and sulfate isn’t involved in the backbone either. So, the sugar in DNA is deoxyribose, paired with phosphate to form the backbone.