lect2 - Bio 1A. Jan. 23, 2009 Lecture 2. Wilt Chemistry...

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Lecture 2. Wilt Chemistry check list Biological Polymers I. Monomers and Polymers A. Almost all the macromolecules found in cells are polymers, which are molecules formed from a string of smaller identical, or similar molecules. The smaller constituents are called monomers. B. Monomers attach to one another by stepwise condensation reactions that remove water (dehydration reaction) , thereby forming a new covalent bond between monomers. This requires input of energy to make the new bond by removing water. Destruction of the bond requires addition of water and is called hydrolysis. C. A relatively small number of monomers can be combined in various ways to make an enormous repertoire of polymers. II. Carbohydrates (sugars) and Polysaccharides A.Monomers 1. The basic structure of a carbohydrate is a chain of carbon atoms, each of which is linked to –OH and –H groups. The number of carbons can vary from 3 to 7. One carbon has either an aldehyde ( aldoses) or ketone (ketoses) group. Thus, the simplest carbohydrate is a 3 carbon unit with an aldehyde group on one end, glyceraldehyde. (glycerol would be the related alcohol). 2. Carbohydrates can vary in: number of carbon atoms aldehyde or ketone arrangement of atoms around an asymmetric carbon substitution of an amino group for hydroxyl oxidation of terminal –OH to carboxyl change -OH to H (deoxy form) 3. Carbohydrates can be diagrammed in a linear form, but in aqueous solution the aldehyde or ketone group can rearrange with the OH group 3 or 4 carbons away to cyclize the molecule, thereby forming a “ring” structure. Please study figures 5.3-5.5 carefully to visualize these structures. You should memorize the structures of glyceraldehyde, ribose, and glucose. These are very important metabolites in all cells. B. Disaccharides 1. Two monosaccharides can be joined by a dehydration reaction between functional groups, forming a glycosidic linkage. (fig. 5.5). Common table sugar, sucrose, is composed of a linkage between the 1 carbon of glucose and the 2 carbon of fructose. C Polysaccharides
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This note was uploaded on 02/27/2009 for the course BIO 1A taught by Professor Schlissel during the Spring '08 term at University of California, Berkeley.

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lect2 - Bio 1A. Jan. 23, 2009 Lecture 2. Wilt Chemistry...

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