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What are polymers?
Large, complex molecules made up of monomers joined together
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Give two examples of polymers...
Proteins&carbohydrates
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What are monomers?
Small, basic molecular units that can form a polymer
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Give two examples of monomers...
Amino acids&monosaccharides
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Which type of reaction results in the formation of a chemical bond between monomers?
Condensation reaction
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What occurs during a condensation reaction?
Water molecule is released
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Which type of reaction breaks the chemical bond between two molecules?
Hydrolysis reaction
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What occurs during a hydrolysis reaction?
Water molecule is used
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Which elements do all carbohydrates contain?
C, H and O
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Glucose is a hexose sugar - what is a hexose sugar?
A monosaccharide with six carbon atoms in each molecule
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Name the two types of glucose...
a-glucose&B-glucose
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What is an isomer?
Molecule with the same molecular formula as another, but atoms connected in different ways
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What are monosaccharides?
Monomers from which larger carbohydrates are made
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How is a disaccharide formed?
Two monosaccharides join together
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What bond forms between two monosaccharides as a water molecule is released
Glycosidic bond
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Which two monosaccharides make up Sucrose?
Glucose&Fructose
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Which two monosaccharides make up Lactose?
Glucose&Galactose
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Which two monosaccharides make up Maltose?
Glucose&Glucose
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Describe the Benedict's test for reducing sugars
Add Benedict's reagent to a sample and heat in water bath.
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Describe the Benedict's test for non-reducing sugars
- Add dilute hydrochloric acid to a new sample and heat in water bath. Then neutralise it by adding sodium hydrogencarbonate. Then heat sample with Benedict's reagent.
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Describe the color change in a reducing sugar test
- Sample stays blue: no reducing sugar present
- Sample forms green→yellow→orange→brick red precipitate then reducing sugar is present
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Describe the color change in a non-reducing sugar test
- Sample stays blue: reducing sugar present
- Sample forms green→yellow→orange→brick red precipitate then non-reducing sugar is present
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How is a polysaccharide formed?
When more than two monosaccharides are joined together by condensation reactions
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Starch is a mixture of which two polysaccharides
Amylose and Amylopectin
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Describe the structure of Amylose
Long, unbranched chain of a-glucose - angles of glycosidic bonds give it a coiled structure which makes it compact so good for storage.
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Describe the structure of Amylopectin
Long, branched chain of a-glucose which side branches allow the enzymes which break down the molecule to get at the glycosidic bonds so glucose can be released quickly.
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Why is starch good for storage?
It is insoluble in water and doesn't affect water potential so water does not enter cells by osmosis.
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How does the function and structure of Glycogen correlate?
Loads of branches means that stored Glucose can be released quickly. Also, its very compact, so good for storage
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Describe the structure and function of Cellulose?
Long, unbranched chains of beta-glucose. When beta-glucose molecules bond, they form straight chains which are linked together by hydrogen bonds to form strong fibres called microfibrils - strong structural support for cells is provided
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Which test is used to indicate the presence of starch?
Iodine test
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Describe the Iodine test?
Add Iodine dissolved in potassium iodide solution to the sample - If starch is present then the solution changes from a browny-orange to a dark, blue-black color.
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Name two types of Lipid
Triglyceride and Fatty acid
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Describe the structure of a Triglyceride
Made up of one glycerol molecule and three fatty acids. The hydrocarbon tails are hydrophobic - lipids are insoluble in water
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Describe the structure of a fatty acid
Two kinds of fatty acid which include saturated and unsaturated. The difference is in their hydrocarbon tails - unsaturated fatty acids have a double bond between carbon atoms
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