B1b - Carbohydrates Flashcards
Elements in carbohydrate
Contains carbon, oxygen and hydrogen
Examples of monosaccharides
Glucose, galactose, fructose
Examples of disaccharides
Sucrose, maltose, lactose
Examples of polysaccharides
Starch, glycogen, cellulose
What is a condensation reaction?
When one monomer joins to another and a water molecule is removed
What is a hydrolysis reaction?
When water molecules are added in the process of breaking bonds between molecules
What is a glycosidic bond?
A chemical bond formed as the result of condensation between two monosaccharides
Structure of starch
Alpha glucose, branched, found in plants only
Structure of glycogen
Alpha glucose, branched, found in animals and fungi
Structure of cellulose
Alpha and beta glucose, unbranched, found in plants only
What are microfibrils?
Cellulose fibres link together by hydrogen bonds which increases strength
Two structural isomers of glucose
Alpha and beta glucose
Test for reducing sugars
Add Benedict’s solution, heat in water bath, if present orange-red precipitate forms
Test for non-reducing sugars
Heat with Benedict’s solution, heat with dilute HCl, neutralise using sodium hydrogencarbonate, test with Benedict’s
Test for starch
Add iodine, if starch present sample turns blue/black
