Saccharides The basic sugars, glucose, fructose, galactose, mannose, are the building blocks of larger more complex carbohydrates. Lactate or lactic acid is the 3-carbon fragment of these sugars, produced as the sugar is oxidized as fuel. The same sugar has two mirror-image forms, determined by the rotation of a test light beam through its crystal in the laboratory. Ribose is important in genetic material, formed into ribonucleic acid, which gives RNA and DNA their long names. Polymers of arabinose are gums like araban.
Sugar alcohols are first cousins of the basic monosaccharides.
O, produces a sugar alcohol with a C-OH group. Sorbitol is such a beast, found as a food additive. Most ingested sorbitol is not absorbed, but passes onto the colon, where bacteria turn it into hydrogen gas. Absorbed sorbitol is metabolized to fructose. Mannitol is another C-OH sweetener, added to commercial foods.