Carbohydrates 2 Flashcards
What is the reverse of a condensation reaction?
Hydrolysis
How do we break the 1-4 glycosidic linkage?
Add water so a hydrolysis reaction can take place.
Give 3 examples of polysaccharides.
Starch, cellulose and glycogen.
What is the monosaccharide that starch is made up of?
alpha-glucose
What is the monosaccharide that glycogen is made up of?
alpha-glucose
What is the monosaccharide that cellulose is made up of?
beta-glucose
What are the types of substances that starch is made up of?
Amylose and amylopectin
Describe the structure of amylose.
It has a spiral structure with alpha-1,4 glycosidic links
Describe the structure of amylopectin.
Coiled springs with a branched structure, alpha-1,4 and alpha-1,6 glycosidic links
What are the properties of starch?
To store energy and is insoluble
How is the energy released from starch?
By hydrolysis of 1,6-glycosidic bonds to release glucose molecules.
How are the branches in amylopectin formed?
Through alpha-1,6-glycosidic linkages.
What is the animal equivalent of starch?
Glycogen
What is the main difference between glycogen and starch?
Glycogen is much more compact and can be hydrolysed quickly.
Compare the structure of glycogen with starch.
It looks a lot like amylopectin with many more branches (caused by alpha-1,6-glycosidic linkages) which are also shorter.
Where do we find cellulose?
In cell walls.
What is the function of cellulose?
Mechanic strength.
What is cellulose a polymer of?
beta-glucose
Explain why cellulose is so strong.
The beta-glucose needs to flip through 180 degrees for C1 and C4 to react in a condensation reaction to form a beta-1,4-glycosidic linkage.
What are the cellulose molecules held together by to form microfibrils?
By hydrogen bonds
Write the order of cellulose molecules from small to large.
Cellulose molecules - microfibrils - fibre - cellulose fibre - cell wall
What is a microfibril?
70 chains of beta-glucose
What is a fibre?
Loads of microfibrils held together.
