DNA is composed of which components?

• A. Bases and Sugars Only
• B. Phosphate, Sugar (Deoxyribose), Base
• C. Phosphate and Base Only
• D. Sugars Only

Answer: (B)

DNA is built from a sugar–phosphate backbone with nitrogenous bases attached to the sugar. Each nucleotide contains three parts: a phosphate group, a deoxyribose sugar, and a nitrogenous base. The phosphate and sugar form the backbone through phosphodiester bonds, linking many nucleotides into a long chain, while the bases extend inward and pair (A with T, C with G) to create the double-helix structure. The sugar is specifically deoxyribose, not ribose, which helps distinguish DNA from RNA. So DNA is composed of phosphate, the deoxyribose sugar, and bases.