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Carbohydrates 2.6 2.6
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Carbohydrates Carbohydrates are made from CARBON, HYDROGEN and OXYGEN
They STORE ENERGY in plants and animals Plant cell walls depend on the structural role of some carbohydrates CARBOHYDRATES MONOSACCHARIDES DISACCHARIDES POLYSACCHARIDES
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What does the ‘n’ stand for? formation of nucleic acid
Monosaccharides Monosaccharides are small organic molecules used as bulding blocks for more complex carbohydrates. Click each of the blue boxes to work through the slide. What does the ‘n’ stand for? General Formula (CH2O)n Number of Carbon atoms TRIOSE, e.g. glyceraldehyde - In metabolic reactions So, when n=3 When n=5 When n=6 PENTOSE, e.g. ribose – formation of nucleic acid HEXOSE, e.g. glucose - main source of energy next
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Isomerism in Glucose C6H12O6
Alpha-glucose CH2OH Oxygen Hydrogen Carbon Hydroxide (OH) beta-glucose Show structural change CH2OH
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Disaccharides Disaccharides form when two monosaccharide units join forming a glycosidic bond, by a condensation reaction. A disaccharide can be made from two of the same monosaccharide molecule or from two different ones. The combination of monosaccharides determines which disaccharide is formed. MONOSACCHARIDES DISACCHARIDE GLUCOSE GLUCOSE GLUCOSE WATER WATER WATER SUCROSE MALTOSE LACTOSE FRUCTOSE GALACTOSE GLUCOSE
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Forming Disaccharides
Glucose CH2OH C O H OH CH2OH C O H OH CH2OH Maltose C O H OH CH2OH OH O OH O H Glycosidic Bond This is a CONDENSATION reaction, where a water molecule is lost.
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What is polymerisation ?
Polysaccharides Polysaccharides are large complex molecules known as POLYMERS. What is polymerisation ? What is a monomer? Click the bubble for the answer Polymerisation is the process of bonding many MONOMERS by condensation reactions to form one large molecule. Monomers are the individual monosaccharides which join to form the polysaccharide. Monomer Glycosidic bond Amylose Glucose 1-4 Polysaccharides Glycogen Glucose 1-4 and 1-6 Cellulose β Glucose 1-4 Next Return to isomerism of glucose
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Forming polysaccharides
Glucose CH2OH CH2OH CH2OH CH2OH C O C O C O C O H H H H H H H H H H H H OH H OH H OH H OH H OH OH OH OH OH OH O O O OH OH O H O H O H H OH H OH H OH H OH In this example, 3 condensation reactions have produced 3 water molecules to produce the polysaccharide. A HYDROLYSIS reaction (addition of water) reverses the reaction and splits the polysaccharide releasing 3 monosaccharide molecules.
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