Macromolecules: Carbohydrates PDF

Macromolecules: Carbohydrates 1 Carbohydrates Function: Provides fast energy for the body, acts as building material and structural support Structure: Occur in multiple forms: monosaccharide, disaccharide, or polysaccharide Consist of C, H, and O atoms typical...

Macromolecules: Carbohydrates 1 Carbohydrates Function: Provides fast energy for the body, acts as building material and structural support Structure: Occur in multiple forms: monosaccharide, disaccharide, or polysaccharide Consist of C, H, and O atoms typically in a 1:2:1 ratio - has a general formula of (CH2O)n Form ring structures in aqueous solutions 2 Monosaccharides Monomer of carbohydrates Simple sugars, 1 ring (3-7 carbons) Classified by number of carbons Major sources of fuel Carbon skeleton serves as raw material for the production of other macromolecules Functional Groups: OH – hydroxyl 3  Monosaccharides **You need to know the structures of these three monosaccharides (pg. 19 of your textbook) and be able to link any two of them together to form a disaccharide Chemical formulas: ____________________ ________________________ ______________________ 4 Monosaccharides Glucose, galactose, and fructose are isomers (same formula but different structures) of each other Each individual monosaccharide also has multiple different isomers such as α-glucose and β-glucose 5 Disaccharides Two monosaccharides are covalently bonded together by a glycosidic linkage α-glucose + α-glucose = maltose Formed by a condensation (dehydration synthesis) reaction Water is removed from two hydroxyl groups 6 Condensation (Dehydration Synthesis) Reaction Note: that the glycosidic linkage is made between two hydroxyl functional groups! 7 Other Disaccharide Examples 8 Polysaccharides Several hundred to thousands of monosaccharides bonded together Examples: glycogen, starch, cellulose, chitin Function: energy storage or structural molecules 9 Storage Polysaccharides Animals: Glycogen Short-term energy storage Depleted in one day unless storage is replenished by consumption of food Chains of α-glucose molecules Highly branched Glycogen is hydrolyzed (broken apart into glucose monomers) when blood sugar drops 10 Storage Polysaccharides Plants: Starch Short-term energy storage Long chains of α-glucose molecules Amylose is a type of simple starch that is unbranched (20-30% of the starch, hard to digest – insoluble in water) Amylopectin is a complex starch that is branched (70% of the starch, soluble, easy to degrade – has many enzyme attachment points) 11 Structural Polysaccharides Chitin: Exoskeleton of insects and crustaceans Cell wall of fungi β-glucose monomers contain an amine group 12 Structural Polysaccharides Cellulose in plants Major component of cell walls Cannot be digested by humans (we lack the enzyme) Consists of β-glucose polymers bonded by beta 1-4 glycosidic linkages 13 Structural Polysaccharides 14