BMCB 658 Lecture Notes - Lecture 13: Hemiacetal, Anomer, Ketose
19 Aug 2016
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Document Summary
More than half of the organic carbon on the planet is starch and cellulose. Major constituent in plant and bacterial cell walls. Monosaccharide: a carbohydrate that cannot be hydrolyzed to a simple carbohydrate. Compounds of formula cnh2non: n varied between 3-8, not all carbohydrates fit this formula. Both are trioses, but carbonyl group is on different carbons. Dihydroxyacetone: ketose: carbonyl on c-2 (c-2 is chiral) Carbohydrates in biological systems tend to be the d form. Diastereomers: stereoisomers that are not mirror images: example: d-erythrose and d-threose are diastereomers. Five-carbon molecules tend to form ring structures to increase their stability. For each d, there is an l (enantiomer) Differ in configuration at one chiral center: example: d-mannose and d-glucose are epimers at c-2. Hemiketals (know the structure of d-glucose both the cyclic and linear forms, as well as -d-glucose and -d-glucose) Carbonyl group on c-2 can react with oh on c-5.
