Which components form the backbone of nucleic acids?

Which components form the backbone of nucleic acids?

• A. Sugar and Phosphate Groups
• B. Nitrogenous bases
• C. Amino acids
• D. Lipids

Answer: (A)

The backbone of nucleic acids is formed by alternating sugar and phosphate groups connected through phosphodiester bonds. In DNA, the sugar is deoxyribose; in RNA, it’s ribose. The 5' phosphate of one sugar links to the 3' hydroxyl of the next sugar, creating a directional, repeating sugar–phosphate chain. The nitrogenous bases attach to the 1' carbon of each sugar and extend outward to form the pairing “rungs” between strands in a double helix (or stand on a single strand in RNA), but these bases are not part of the backbone itself. Amino acids and lipids are components of proteins and membranes, not nucleic acids, so they aren’t part of the backbone.

The backbone of nucleic acids is formed by alternating sugar and phosphate groups connected through phosphodiester bonds. In DNA, the sugar is deoxyribose; in RNA, it’s ribose. The 5' phosphate of one sugar links to the 3' hydroxyl of the next sugar, creating a directional, repeating sugar–phosphate chain. The nitrogenous bases attach to the 1' carbon of each sugar and extend outward to form the pairing “rungs” between strands in a double helix (or stand on a single strand in RNA), but these bases are not part of the backbone itself. Amino acids and lipids are components of proteins and membranes, not nucleic acids, so they aren’t part of the backbone.