aldopentose

Lyxose is an aldopentose - a monosaccharide containing five carbon atoms, and including an aldehyde functional group.

Xylose is classified as a monosaccharide of the aldopentose type, which means that it contains five carbon atoms and includes a formyl functional group.

Ribose is an aldopentose (a monosaccharide containing five carbon atoms) that, in its open chain form, has an aldehyde functional group at one end.

The furanose ring is a cyclic hemiacetal of an aldopentose or a cyclic hemiketal of a ketohexose.