Carbohydrates

Created by

georgia.w

Cards (23)

Monosaccharides have the general formula Cn(H2O)n
What is a monosaccharide? 
A monomer made of one sugar molecule
What do monosaccharide chains form?
Polysaccharides
What is a disaccharide? 
A disaccharide is a type of carbohydrate composed of two monosaccharide units joined together by a glycosidic bond.
What are three examples of a disaccharide? 
Maltose, Sucrose, Lactose
How do monosaccharides join together?
In a condensation reaction, which forms a glycosidic bond.
What is a polysaccharide?
A polymer made up of many monosaccharides joined together
Three main polysaccharides? 
Starch, Glycogen, Cellulose
What is the structure of starch?
Starch is a polysaccharide composed of alpha glucose units linked together in a linear chain (amylose) or branched chains (amylopectin).
What is the function of starch?
Energy storage
How does starch's structure help its function?
It is insoluble and so not affected by osmosis, and it is highly compact to allow for lots of sugar storage.
What is the structure of glycogen?
Glycogen is a branched polymer of alpha glucose molecules linked together by alpha-1,4-glycosidic bonds with alpha-1,6-glycosidic bonds at the branch points.
How does the structure of glycogen help its function?
Branching structure allows for rapid synthesis and breakdown of glucose molecules, providing quick energy storage and release.
What is the structure of Cellulose?
Beta glucose units help together by 1-4 glycosidic bonds. It has long and unbranched chains.
What is the function of cellulose?
The function of cellulose is to provide structural support in plant cell walls.
How does the structure of cellulose helps is function?
As the B-glucose units have to flip, the chain is unbranched as so has good strength in a cell wall.
How is starch digested?
Starch hydrolysed into maltose by salivary and pancreatic amylase.
Maltose is hydrolysed into glucose by maltase in intestinal juice.
How is glycogen digested?
Hydrolysed into glucose by B-cells in the islets of Langerhans which secrete glucagon, which activates enzymes for hydrolysis.
How is cellulose digested? 
Herbivores only (humans cannot digests and so don't have cellulose) have bacteria's in their digestive system that break it down
Known as cellulase.
Test for Starch? 
Add 2-3 drops of iodine
Blue/Black precipitate formed if positive.
Test for reducing sugars?
Add Benedict's to the sample, mix and heat to 70 degreed Celsius in a water bath. Positive result is blue, green, yellow, orange or brick red precip.
Test for non reducing sugars?
Add dilute HCl, boil, cool and add NaOH to neutralise, then add benedict's, heat in water bath, and a positive result will show a brick red precipitate.
What is a glycaemic index? 
Measure of how quickly a food raises blood sugar levels.