Which sugar is found in RNA but not in DNA?

Ribose is the sugar that is specifically found in RNA. It is a five-carbon sugar (pentose) that plays a crucial role in the structure of RNA molecules. The presence of an -OH (hydroxyl) group on the second carbon of ribose distinguishes it from deoxyribose, the sugar found in DNA. In contrast, deoxyribose lacks this hydroxyl group at the same position, which contributes to the stability and structural differences between DNA and RNA.

While glucose and mannose are also sugars, they are not components of either RNA or DNA. Therefore, the identification of ribose as the sugar present in RNA, and its absence in DNA, is definitive and underscores the biochemical distinction between these two nucleic acids.