polysaccharides

How are polysaccharides formed?

the condensation of many glucose molecules

3 types of polysaccharides?

• Starch

• Glycogen

• Cellulose

What is starch made up off?

Amylose and Amylopectin

What is starch found in and stored in?

• Potatoes, rice

• Plants store excess glucose as starch

Structure of amylose in starch?

• ą 1-4 glycosidic linkage (joins at carbon 1&4)

• Straight chain that’s coiled (because of the angle the linkage forms at)

Structure of amylopectin in starch? And why?

• ą 1-4 glycosidic linkage (the main chain)

• a 1-6 glycosidic linkage (every 25 glucose)

• Easier to break off glucose for energy in plants

Function of starch and glycogen?

Energy storage

• Starch stored in e.g chloroplasts

• Glycogen - muscle and liver cells - hydrolysed into glucose

Structure of glycogen?

• ą 1-4 glycosidic linkage

• ą 1-6 glycosidic linkage

• Highly branched

• (Same structure as amylopectin but more branched)

Features of glycogen and why is this useful ?

• Highly branched - easily broken down into glucose (fast supply of energy)

• Insoluble in water - doesn’t change water potential (water in and out of cell)

Structure of cellulose? Features?

• B 1-4 glycosidic linkage

• Straight chain - every other B glucose is inverted (flip everytime)

• Allows hydroxyl groups - form hydrogen bonds - produces microfibriles (tight bundles) - supportive structure

• Insoluble in water

Function of cellulose?

Structural support

• Microfibriles form meshwork to support the cell wall

How is glycogen and starch formed?

The condensation of ą glucose

How is cellulose formed?

Condensation of B glucose