Polysaccharides • Are polymers of monosaccharides.• Hydrolysis produces many molecules of

monosaccharide.• Can be formed from pentoses or the 5 carbon

sugars or the hexoses or six carbon sugars.• Those from pentoses are called pentosans• Those from hexoses are hexosans or

sometimes called the glucosans.• The hexosans are most common in terms of

physiology.• The hexosans have the general formula ( )x

Polysaccharides

The hexosans have the general formula ( )x.

Where x is a large number.Some of the common hexosans are starch, cellulose and dextrin.

Starch

Insoluble in waterGives a characteristic blue color

with iodine.Test is used to determine the

presence of starch in any solution or even to test for iodine.

Amylose Nonbranched polysaccharide

present in starch to an extent of 15 to 20%

When starch is hydrolyzed, it form dextrin (amylodextrin, erythrodextrin, achroodextrin) than maltose and finally glucose.Erythrodextrins turns red in the presence of iodine.Both maltose and glucose produce no color.

Starch erythrodextrin maltose glucose blue red colorless colorless

CelluloseThe supporting and structural substance of plants.It gives bulk to the feces and prevents constipation.Does not dissolve in water.Gives no color test with iodine.gives a negaive test with Cu2+ complex ion.used to make rayon.Wood, cotton and paper are composed primarily of cellulose.

Glycogen Is present in the body and stored in the

liver and muscles.Where it supplies glucose.Forms a colloidal solution in water and

gives a red color with iodine.Glycogen is formed in the body cells

from molecules of glucose. In a process called glycogenesis.

When glycogen is hydrolyzed to glucose, the process is called glycogenolysis.

Dextrin Produced during the hydrolysis of starch.An intermediate between starch and maltose.Used in the preparation of adhesives.Forms sticky colloidal suspensions with water.

Heparin Is a polysaccharide used as blood anticoagulant.It accelerates the inactivation of thrombin and other blood-clotting agentsIt’s the strongest organic acid found in the body

Dextran Produced by certain bacteria when they are grown on sucrose.Used as blood extenders to hold water in the bloodstream and help prevent drops in the blood volume and blood pressure.Dextrans growing on the surfaces of teeth are an important component of dental plaque.