Carbohydrates Organic compounds which comprise of only C, H and O C x (H 2 O) y
Carbohydrates Monosaccharides Simple sugar Soluble in water Precursors in synthesis triose sugars of other (C3) molecules (fats, nucleic acids, amino acids) pentose sugars (C5) hexose sugars (C6) Polysaccharides Insoluble in water Glycogen = storage in liver and muscles in animals Starch = storage in plant Storage form of carbohydrates cells
Structure of Carbohydrates Aldose sugar Ketose sugar
Structure of Carbohydrates In aqueous solution these sugars undergo an internal reaction resulting ring structures
How many chiral carbons are present in glucose?
How many chiral carbons are present in glucose? 4
Structure of Carbohydrates Haworth projection formulas Bold lines closest to you Alpha glucose CH 2 OH and C 1 OH are on opposite side C on ring are omitted Beta glucose CH 2 OH and C 1 OH are on same side
Types of Carbohydrate Monosaccharides Disaccharides Polysaccharides
Monosaccharides into disaccharides + 1, 4 Glycosidic link Maltose A condensation reaction occurs to join the 2 monosaccharides H2O
Monosaccharides to disaccharides
Disaccharide into monosaccharides H2O A hydrolysis reaction occurs to split the disaccharide into 2 monosaccharides α-glucose α-glucose
Condensation or hydrolysis? Monosaccharide into disaccharide = Disaccharide into monosaccharide =
Condensation or hydrolysis? Monosaccharide into disaccharide = condensation (water given off) Disaccharide into monosaccharide = hydrolysis (water needed to split)
Glycogen is a branched polysaccharide which contains α-glucose molecules linked with both 1 4 and 1 6 glycosidic bonds. Use the structure of α-glucose in your IB data booklet to draw a section of the molecule showing both types of linkages.
Glycogen is a branched polysaccharide which contains α-glucose molecules linked with both 1 4 and 1 6 glycosidic bonds. Use the structure of α-glucose in your IB data booklet to draw a section of the molecule showing both types of linkages.
Polysaccharides Glucose makes up cellulose, starch and glycogen For each of the above find out: 1. Structure 2. How the structure affects the properties 3. The function of each of these in plants (starch and cellulose), and animals (glycogen)
Starch The α-helical structure of starch makes it good for storage (it s compact!) Starch is insoluble due to its structure It is therefore the main plant storage sugar for energy
Cellulose Polymer of β-glucose Each monomer is inverted. Has consequences for its properties
Cellulose Forms chains which run parallel with hydrogen bonds between the chains to form microfibrils Microfibrils are strong Being fibrous, cellulose is structurally important in plant cell walls
Glycogen Very similar to starch Has more branching Stored in the liver Insoluble Acts as a store of energy in animals (same as starch in plants)
Glucose is not the only monosaccharide Fructose: Glucose and fructose combine to form sucrose (a disaccharide)
Glucose is not the only monosaccharide Galactose Glucose and galactose combine to form Lactose Galactose Glucose
What makes what? α-glucose + α-glucose = maltose The polymer of α-glucose is starch/glycogen The polymer of β-glucose is cellulose Glucose + fructose = sucrose Glucose + galactose = lactose