Pentose(redirected from Five-carbon sugar)
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a monosaccharide that contains five carbon atoms per molecule. In nature, pentoses do not occur in the free state but are present in various glycosides and polysaccharides that are commonly found in plants; these include arabinose and xylose. The pentoses ribose and 2-deoxyribose are constituents of nucleic acids. Nucleoside-diphosphate sugars participate in the insertion of arabinose and xylose into complex carbohydrates. Ribose in the form of ribose-5-phosphate, which takes part in the biosynthesis of nucleotides, is formed as an intermediate product in photosynthesis and in the pentose-phosphate cycle. Pentoses are converted by mineral acids into furfurol, a valuable raw material in the chemical industry.