2597890
Description
Flashcards by Charlotte Hewson, updated more than 1 year ago
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Created by Charlotte Hewson
over 11 years ago
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| Question | Answer |
| what name is given to one monomer? | monosaccharide |
| what name is given to a pair of monosaccharide's? | disaccharides |
| what is the name given to larger numbers of monosaccharide's? | polysaccharides |
| what three substances can be formed by a disaccharide? | maltose, sucrose and lactose |
| how id maltose formed? | Glucose+glucose |
| how is sucrose formed? | Glucose + fructose |
| how is lactose formed? | Glucose + galactose |
| what happens when monosaccharide's join? | a molecule of water is removed |
| what is the name for this reaction? | condensation reaction |
| what is the name of the bond formed? | glycosidic bond |
| how can you break this bond? | add water |
| what does this do? | releases the constituent monosaccharide's |
| what is this process called? | hydrolysis reaction |
| what do you use to test for reducing sugars? | Benedict's test |
| what must be done to test for a non-reducing sugar? | it must be broken down into its monosaccharide components by hydrolysis |
| what is done first to check the sample? | goes through benedict's test. if no colour change, its a non-reducing sugar |
| what do you then add to the sample? | dilute hydrochloric acid |
| what do you do to this mix? | put it in gently boiling water for 5 mins |
| what will this acid do? | hydrolyse the disaccharides into monosaccharides |
| what do you then add? | sodium hydrogencarbonate solution |
| why do you do this? | to neutralise it as Benedict's reagent wont work in acidic conditions |
| how do you check that the solution is neutralised? | test with pH paper |
| what is the next step? | re-test by heating with benedict's reagent |
| what will happen if non-reducing sugar was present in original sample? | benedict's solution will go orange-brown. |
| why does this happen? | reducing sugars were produced from the hydrolysis of non-reducing sugars |
| what feature makes polysaccharides suitable for storage? | insoluble |
| what is an example of a polysaccharide found in plants? | starch |
| what is it found in the form of? | small granules or grains |
| how is starch formed? | linking between 200 and 100,000 alpha-glucose molecules |
| how do you test for starch? | add iodine solution and stir/shake |
| what will happen if starch is present? | solution will go from yellow to blue-black |
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