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WJEC GCE BIOLOGY Carbohydrates 2.6. WJEC GCE BIOLOGY Carbohydrates Carbohydrates are made from CARBON, HYDROGEN and OXYGEN Plant cell walls depend on.

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Presentation on theme: "WJEC GCE BIOLOGY Carbohydrates 2.6. WJEC GCE BIOLOGY Carbohydrates Carbohydrates are made from CARBON, HYDROGEN and OXYGEN Plant cell walls depend on."— Presentation transcript:

1 WJEC GCE BIOLOGY Carbohydrates 2.6

2 WJEC GCE BIOLOGY Carbohydrates Carbohydrates are made from CARBON, HYDROGEN and OXYGEN Plant cell walls depend on the structural role of some carbohydrates They STORE ENERGY in plants and animals MONOSACCHARIDES CARBOHYDRATES POLYSACCHARIDESDISACCHARIDES

3 WJEC GCE BIOLOGY Carbohydrates (CH 2 O) n 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. General Formula What does the n stand for? Number of Carbon atoms So, when n=3 TRIOSE, e.g. glyceraldehyde - In metabolic reactions When n=5 When n=6 HEXOSE, e.g. glucose - main source of energy PENTOSE, e.g. ribose – formation of nucleic acid next

4 WJEC GCE BIOLOGY Carbohydrates Isomerism in Glucose C 6 H 12 O 6 CH 2 OH Alpha-glucose beta-glucose Show structural change Oxygen Hydrogen Carbon Hydroxide (OH)

5 WJEC GCE BIOLOGY Carbohydrates GLUCOSE MALTOSESUCROSE GLUCOSE Disaccharides A disaccharide can be made from two of the same monosaccharide molecule or from two different ones. Disaccharides form when two monosaccharide units join forming a glycosidic bond, by a condensation reaction. The combination of monosaccharides determines which disaccharide is formed. MONOSACCHARIDESDISACCHARIDE FRUCTOSEGALACTOSE WATER LACTOSE GLUCOSE

6 WJEC GCE BIOLOGY Carbohydrates O OH Forming Disaccharides C C C CO C H OH H H CH 2 OH H H C C C CO C H OH H H CH 2 OH H H C C C CO C H OH H H CH 2 OH H H C C C CO C H OH H H CH 2 OH H H O HH Glycosidic Bond This is a CONDENSATION reaction, where a water molecule is lost. Glucose Maltose

7 WJEC GCE BIOLOGY Carbohydrates Polysaccharides Polysaccharides are large complex molecules known as POLYMERS. Monomers are the individual monosaccharides which join to form the polysaccharide. Polymerisation is the process of bonding many MONOMERS by condensation reactions to form one large molecule. Polysaccharides MonomerGlycosidic bond Cellulose β Glucose 1-4 Amylose Glucose 1-4 Glycogen Glucose 1-4 and 1-6 Return to isomerism of glucose Return to isomerism of glucose Next What is polymerisation ? What is a monomer? Click the bubble for the answer

8 WJEC GCE BIOLOGY Carbohydrates O OH Forming polysaccharides C C C CO C H OH H H CH 2 OH H H C C C CO C H OH H H CH 2 OH H H O HH In this example, 3 condensation reactions have produced 3 water molecules to produce the polysaccharide. O HH C C C CO C H OH H H CH 2 OH H H C C C CO C H OH H H CH 2 OH H H OH Glucose O O HH O A HYDROLYSIS reaction (addition of water) reverses the reaction and splits the polysaccharide releasing 3 monosaccharide molecules.

9 WJEC GCE BIOLOGY Carbohydrates You can give this question a go, in order to prove your understanding:


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