Which molecule is described as a nucleic acid with ribose as its sugar, a phosphate backbone, and nitrogenous bases?

Which molecule is described as a nucleic acid with ribose as its sugar, a phosphate backbone, and nitrogenous bases?

• A. RNA
• B. DNA
• C. Carbohydrate
• D. Protein

Answer: (A)

RNA is a nucleic acid whose sugar is ribose, linked by a phosphate backbone, with nitrogenous bases such as adenine, guanine, cytosine, and uracil. The key distinction from DNA is the sugar: RNA uses ribose, which has a hydroxyl group on the 2' carbon, whereas DNA uses deoxyribose and replaces thymine with uracil. The backbone of RNA is formed by phosphodiester bonds connecting sugar and phosphate groups, giving it the familiar chain-like structure. Carbohydrates and proteins are not nucleic acids, so they don’t fit this description. This combination of ribose sugar, phosphate backbone, and the specific bases identifies the molecule as RNA.

RNA is a nucleic acid whose sugar is ribose, linked by a phosphate backbone, with nitrogenous bases such as adenine, guanine, cytosine, and uracil. The key distinction from DNA is the sugar: RNA uses ribose, which has a hydroxyl group on the 2' carbon, whereas DNA uses deoxyribose and replaces thymine with uracil. The backbone of RNA is formed by phosphodiester bonds connecting sugar and phosphate groups, giving it the familiar chain-like structure. Carbohydrates and proteins are not nucleic acids, so they don’t fit this description. This combination of ribose sugar, phosphate backbone, and the specific bases identifies the molecule as RNA.