How does the role and structure of the following polysaccharides compare?

Question

a. starch

b. glycogen

c. cellulose

Answer 1

Cellulose are structural molecules. It's the most abundant natural polymer on earth and is the prinipal strength and support of trees and plants. It's structure is a homopolymer of glucose with linkage beta(1,4)

Starch and Glycogen are storage molecules. They are both also homopolymers of glucose, but their linkage is alpha(1,4). They also have an alpha(1,6) branchpoint from time to time. These branches occur every 12-30 residues in starch, and every 8-12 residues in glycogen.

Answer 2

Starch and Cellulose are  plant  Poly saccharides whereas Glycogen is an animal Polysaccharide .In Starch and Glycogen the repeating Glucose units are linked by Alpha Acetal ( 1-4 linkage(Amylose) and 1-6 (Amylopectin)} linkages.In starch there are 12 to 20 glucose units between branches and in Glycogen 8 to 12 units of Glucose.In Cellulose the linkage is Beta 1-4  linkage.Animals have enzymes to break Alpha 1-4 and 1-6 linkages---but do not have enzymes to break Beta1-4 linkages.Ruminants which eat grass(Cellulose) have 4 stomachs--In 3 stomachs there are bacteria which can break Beta 1-4 linkage and release maltose and Glucose for the ruminant to digest.Bacteria also thrive by the process of Symbiosis.