Polymers made of 100s of monosaccharide units MUs

• Polymers made of 100’s of monosaccharide units (MUs) • A condensation reaction occurs between each MU and are held together with glycosidic bonds • Molecules can be branched or unbranched • Are insoluble and not sweet to taste • Storage polysacs are folded to give compact molecules • Structural polysacs are coiled or straight chained

Polysaccharides • Starch: plant storage • Glycogen: animal storage • Cellulose: structural support

• Main carbohydrate food reserve in plants • A polymer made up of many a glucose molecules held together by GLYCOSIDIC BOND • Made of two compounds – amylose and amylopectin

• Long chains of a glucose molecules linked by 1, 4 glycosidic bonds • Chains are coiled to form a spiral held in place by hydrogen bonds

• Long chains of a glucose molecules linked by 1, 4 glycosidic bonds • Has some 1, 6 glycosidic linkages giving it a branched structure

What makes starch a good food store? • Compact – for storage • Insoluble - no affect on osmotic balance of cell • Readily converted into sugar – many side branches

• similar to amylopectin, made up of chains of a glucose • But has many more 1, 6 glycosidic side branches

Function • Very compact storage molecule found in mammalian liver (and muscles) • Increased branching allows for quick hydrolysis to release glucose • Means very quick energy release

• Made up of long, unbranched chains of b glucose • Individual chains are linked to each other by hydrogen bonds • Overall structure is of long, strong microfibrils • These form layers at different angles to each other, giving high tensile strength

CELLULOSE H O b glucose HO HO O OO b glucose OH H H HO O b glucose OH H O H OH OH b glucose O OOH H HO H O H OH

Function • Structural polysaccharide in plants • Cellulose cell walls provide high tensile strength to plant cells • H-bonds prevent water entering the molecule • Makes it resistant to hydrolysis from enzymes