The sugar in RNA is called ribose. Ribose is a five-carbon sugar (a pentose) with the molecular formula C₅H₁₀O₅. It alternates with phosphate groups to form the backbone of the RNA molecule and binds to nitrogenous bases

. The key difference between the sugar in RNA and DNA is that RNA contains ribose, which has a hydroxyl group (-OH) attached to its 2' carbon, whereas DNA contains deoxyribose, which lacks this oxygen atom at the 2' carbon (having just a hydrogen instead). This difference makes RNA more chemically reactive and less stable than DNA

. In summary:

• RNA sugar: Ribose (with an -OH group at the 2' carbon)
• DNA sugar: Deoxyribose (with an -H instead of -OH at the 2' carbon)

This structural difference is fundamental to the distinct functions and stability of RNA and DNA molecules