Ribose
Ribose is a five carbon sugar (pentose) that is critical to living creatures. It is a component of the RNA that is used for genetic transcription, and is related to deoxyribose which is a component of DNA. It is also a component of ATP, NADH, and several other chemicals that are critical to the metabolic process.
Refer to the article on Deoxyribose for more information on both sugars, how they relate to each other, and how they relate to genetic material.
Isomerism
D-Ribose has the same configuration at its penultimate carbon as D-glyceraldehyde.