Which components make up the backbone of DNA?

Which components make up the backbone of DNA?

• A. Deoxyribose sugar and a phosphate group
• B. Adenine and Thymine
• C. Guanine and Cytosine
• D. Deoxyribose sugar only

Answer: (A)

DNA's backbone is the alternating sugar and phosphate framework connected by phosphodiester bonds. The backbone is made from deoxyribose sugar units linked to phosphate groups, with nitrogenous bases (A, T, C, G) extending from the sugar to form the rungs of the ladder. The bases themselves do not make up the backbone; they pair across the two strands to hold the double helix together. So the combination of deoxyribose sugar and a phosphate group constitutes the backbone. The other options name the bases or only the sugar, which does not describe the backbone.

DNA's backbone is the alternating sugar and phosphate framework connected by phosphodiester bonds. The backbone is made from deoxyribose sugar units linked to phosphate groups, with nitrogenous bases (A, T, C, G) extending from the sugar to form the rungs of the ladder. The bases themselves do not make up the backbone; they pair across the two strands to hold the double helix together. So the combination of deoxyribose sugar and a phosphate group constitutes the backbone. The other options name the bases or only the sugar, which does not describe the backbone.