Need-To-Know Guide, Chapters 7 Chapter 7: Carbohydrates Memorize the structure of glucose, ribose, and deoxyribose: both the cyclic and extended chain conformation. You do not need to memorize any other monosaccharide structures. (Why ribose and deoxyribose, you ask? These sugars are integral parts of RNA and DNA, which we will cover in Ch. 8). Understand naming conventions: aldose vs. ketose; hexose, pentose, triose, etc. Understand the difference between an anomer and an epimer. You should be able to look at two structures and decide whether they are epimers or anomers (or neither). You should be able to tell an a- from a b- anomer (see Fig. 7.6). Understand the chemical reaction that yields disaccharides: the hydroxyl of one monosaccharide adds to the anomeric carbon of the second monosaccharide to form an acetal called a glycoside; this is a glycosidic bond. You should be able to recognize a drawing of a glucose-glucose disaccharide and name it based on the naming convention (i.e. Glc(b1à4)Glc) (order of monosaccharide units, configuration at each anomeric carbon, carbon atoms involved in glycosidic linkage). The reducing end is so named because the polysaccharide can get oxidized from a carbonyl to a carboxyl. Not all polysaccharides have a reducing end. For a disaccharide with no reducing end, this is indicated by a double-headed arrow in the naming convention. You should recognize the meaning of the double-headed arrow, but you will not have to draw or name non-reducing disaccharides. Polysaccharides: Understand the difference between branched and unbranched polysaccharides. Remember that these fold into tertiary structures that are influenced by hydrogen bonding and steric factors. Understand why starch and cellulose have such different structural properties even though the monosaccharide units are the same. Finally, it is important to understand how proteins and carbohydrates interact in biology, especially lectins and glycoproteins. What are N-linked and O-linked carbohydrates? Can you draw them? Glycolipids are important too, and are covered in depth in Ch. 10. Be able to distinguish glycoproteins, proteoglycans, peptidoglycans, and lectins.