POLYSACCHARIDES Flashcards
What is starch and glycogen?
The storage polysaccharides found in plants (starch) and animals (glycogen)
They are both made of alpha glucose
Starch is actually a mixture of 2 polysaccharides - amylose and amylopectin
What are the features of starch?
It is insoluble - it doesn’t affect water potential of the cell, meaning water isn’t taken into the cells by osmosis
It is a large molecule - it won’t cross the cell surface membrane and escape the cell
It is a polymer of glucose - this means it can be broken down quickly, produing glucose for respiration
Amylose is coiled, making the molecule compact so more can be stored in the cell
Amylopectin is branched, so there are more ends that can be broken down by the ends, meaning more rapid glucose release
What are the features of glycogen?
It is stored as small granules in the liver.
It is insoluble, not affeccting water potential and not causing osmosis
It is compact, forming coils meaning more can be stored in the cell
It is a highly branched molecule, so more ends can be acted upon by enzymes meaning more glucose release
What is cellulose, what is it made of, what are its features?
The polysaccharide found in the cell wall, providing structural support and rigidity. it is made out of beta glucose, rather than alpha. It is also insolube and quite strong.
What is the structure of cellulose?
It forms straight, unbranched chains, parallel to each other.
Beween the molecules, many hydrogen bonds between parallel chains strengthen the structure, although they are weak individually. There are also 1-4 glycosidic bonds. Hydrogen bonding causes microfibril formation
