Xylose

Xylose (cf. Greek ξυλος, xylos, "wood") is a sugar first isolated from wood, and named for it. Xylose is classified as a monosaccharide of the aldopentose type, which means that it contains five carbon atoms and includes a formyl functional group. It is the precursor to hemicellulose, one of the main constituents of biomass. Like most sugars, it can adopt several structures depending on conditions. With its free carbonyl group, it is a reducing sugar.