Furanoses

Glucose is a sugar with the molecular formula . It is the most abundant monosaccharide, a subcategory of carbohydrates. It is made from water and carbon dioxide during photosynthesis by plants and most algae. It is used by plants to make cellulose, the most abundant carbohydrate in the world, for use in cell walls, and by all living organisms to make adenosine triphosphate (ATP), which is used by the cell as energy. Glucose is often abbreviated as Glc.

Fructose (), or fruit sugar, is a common monosaccharide, i.e. a simple sugar. It is classified as a reducing hexose, more specifically a ketonic simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. A white, water-soluble solid, it is one of the three dietary monosaccharides, along with glucose and galactose. Fructose is found in honey, tree and vine fruits, flowers, berries, and most root vegetables.

Galactose (, galacto- + -ose, sometimes abbreviated Gal), is a common monosaccharide, i.e. a simple sugar. It is classified as a reducing hexose, more specifically an aldohexose. In terms of structure, it is a C-4 epimer of glucose. A white, water-soluble solid, it is about 80–90% as sweet as glucose and about 65% as sweet as sucrose.

Deoxyribose, or more precisely 2-deoxyribose, is a monosaccharide with idealized formula H−(C=O)−(CH2)−(CHOH)3−H. Its name indicates that it is a deoxy sugar, meaning that it is derived from the sugar ribose by loss of a hydroxy group. Discovered in 1929 by Phoebus Levene, deoxyribose is most notable for its presence in DNA. Since the pentose sugars arabinose and ribose only differ by the stereochemistry at C2′, 2-deoxyribose and 2-deoxyarabinose are equivalent, although the latter term is rarely used because ribose, not arabinose, is the precursor to deoxyribose.

Mannose is a sugar with the formula , which sometimes is abbreviated Man. It is one of the monomers of the aldohexose series of carbohydrates. It is a C-2 epimer of glucose. Mannose is important in human metabolism, especially in the glycosylation of certain proteins. Several congenital disorders of glycosylation are associated with mutations in enzymes involved in mannose metabolism.

Xylose ( , , "wood") is a common monosaccharide, i.e. a simple sugar. Xylose is classified as aldopentose type, which means that it contains five carbon atoms and includes an aldehyde functional group, at least in its open-chain form. It is abundant in biomass, and is one of the most abundant sugars in nature. It is a white, water-soluble solid.

Arabinose is an aldopentose – a monosaccharide containing five carbon atoms, and including an aldehyde (CHO) functional group.

Altrose is an aldohexose sugar. D-Altrose is an unnatural monosaccharide. It is soluble in water and practically insoluble in methanol. However, L-altrose has been isolated from strains of the bacterium Butyrivibrio fibrisolvens.

thumb|160px|Beta--fructofuranose A furanose is a collective term for carbohydrates that have a chemical structure that includes a five-membered ring system consisting of four carbon atoms and one oxygen atom. The name derives from its similarity to the oxygen heterocycle furan, but the furanose ring does not have double bonds.

D-Psicose (C6H12O6), also known as D-allulose or simply allulose, is an epimer of fructose that is used by some commercial food and beverage manufacturers as a low-calorie sweetener. Allulose occurs naturally in small quantities in a variety of foods. It was first identified in the 1940s, although the enzymes needed to produce it on an industrial scale were not discovered until the 1990s.

Xylulose is a ketopentose, a monosaccharide containing five carbon atoms, and including a ketone functional group. It has the chemical formula . In nature, it occurs in both the L- and D-enantiomers. 1-Deoxyxylulose is a precursor to terpenes via the DOXP pathway. == Pathology == L-Xylulose accumulates in the urine in patients with pentosuria, due to a deficiency in L-xylulose reductase. Since L-xylulose is a reducing sugar like D-glucose, pentosuria patients have been wrongly diagnosed in the past to be diabetic.

Lyxose is an aldopentose — a monosaccharide containing five carbon atoms, and including an aldehyde functional group. It has chemical formula . It is a C'-2 carbon epimer of the sugar xylose. The name "lyxose" comes from reversing the prefix "xyl" in "xylose".

Fuculose or 6-deoxy-tagatose is a ketohexose deoxy sugar. Fuculose is involved in the process of sugar metabolism. -Fuculose can be formed from -fucose by -fucose isomerase and converted to L-fuculose-1-phosphate by -fuculose kinase. == See also == -fuculose-phosphate aldolase -fuculosekinase

-Glucose is an organic compound with formula C6H12O6 or O=CH[CH(OH)]5H, specifically one of the aldohexose monosaccharides. As the -isomer of glucose, it is the enantiomer of the more common -glucose.