Lecture 26 Glycogen Synthesis-BW

Cyclize 13 23 position of hydroxyl group at c 1

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Unformatted text preview: Position of hydroxyl group at C-1 (anomeric carbon) designates the position when drawn down below the ring; the position is indicated when drawn up above the ring. 4/15/13 MCB 2000 Lecture 26 Carbohydrate Chemistry Open chain of fructose (ketose) cyclizes to a 5-membered ring. and anomers are possible. Fructose - ketone where aldheye on glucose. number two carbon (ketone) and number 5 carbon has hydroxyl. to form ring stucture carbon number 1 and 5. 4/15/13 MCB 2000 Lecture 26 Link to polysarrchies together - maltose- linking the alpha carbon hydroxyl in down position and linking to carbon number 4. - hydroxyl group in the middle - alpha 1,4 linkage. (bond)-covalent bond. forming a covalent between the two mono The O-Glycosidic Bond Monosaccharides are joined together by a glycosidic bond (the anomeric carbon reacts with an oxygen on the hydroxyl group). Carbon number 1 -reacts with the oxygen - allows for the linkage to occur enzyme catalyic not s pontaneous. Maltose The bond can be either or . The numbering indicates which carbons are joined together 4/15/13 MCB 2000 Lecture 26 Important Polysaccharides all contain glucose. -how to tell the different between cellulose to starch to glyocgen. the type of glyosidic bond - is it alpha or beta and what c arbons are being linked together. c ellulose and starch are poly in plants. within the starch group have two differnet types - dictated by there stucutre. same linkage but one will have additoinal type of glycosidic bond. glycogen found in aniamsl. plants dont have glyocgen. Cellulose (plants) Starch (plants) Amylose Amylopectin Glycogen (animals) All contain glucose as the monosaccharide; the differences are due to or -glycosidic linkages and structure 4/15/13 MCB 2000 Lecture 26 AMylose- alpha 1,4 glyoclsidic bonds - completely linear. - can see alpha 1,4 glycosidic bond - linkage 1 gluocse molecule to to the next. amylopectin has the alpha 1 4 linage - additonal type of bond - alpha 1 6. the alpha 1.6 in amylopectin gives a branch stuture. can form a longer branch. amylose - strictly linear where amylopectin - branched stucture. some branches longer then others. two types of bond- alpha 1,4 and 16 Polysaccharides have 2 major functions: energy storage and structural support A m y lose (st a r c h) is a l i n e a r pol y m e r of gl u cose F i g. 16-15, p.445 4/15/13 A m y lo p e c t i n (st a r c h) a n d gl y coge n a r e b r anched p o l y s a c c h a r i d es. B o n d s a r e -1 , 4 w i t h i n t h e c h a i n a n d -1 , 6 a t b r a n c h p o i n t s. MCB 2000 Lecture 26 Starch and celluose - same purpose - energy storage. cellulose - plants have a cell wall - rigid. - the cellulose is a highily crossed linked poly. look a lot of hydrogen bonding - very similar to beta sheet. cellulose poly. have three layers. the layers are linked togehter by hydrogen bonding - gives y ou rigid. difference: cellulose is BETA not alpha. humans cant digest celluose - dont have the enzyme that can break the bet...
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This note was uploaded on 09/17/2013 for the course MCB 2610 / 200 taught by Professor Feldman during the Fall '12 term at UConn.

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