Carbohydrate polysaccharides

polysaccharide are the storage energy sources

1. CARBOHYDRATE- POLYSACCHARIDES MRS. PRAVEEN GARG VITS COLLEGE, SATNA

2. INTRODUCTION Polysaccharides are macromolecules, in which several monosaccharides are linked by glycosidic bond. It has more than 10 monosaccharides residue. Generally polysaccharides are called as ‘ Glycans ’. Polysaccharides produce several monosaccharides or its derivatives on hydrolysis by acid and enzymes. The general formula of polysaccharides is ( C 6 H 10 O 5 ) n . Its contain similar or different type of monosaccharides unit.

3. Polysaccharide can be divided in to two types. Homo-polysaccharides: It contain only same type of monosaccharide unit. It can be storage or structural form. It is also known as homo glycans . Example : Starch, glycogen, cellulose, chitin, pectin, mannan , xylan , fructans etc. Hetero-polysaccharides: It contain different type of monosaccharide unit. It is also known as hetero glycans . Example : Peptidoglycon , heparin, glucoprotein etc.

4. STARCH It is storage polysaccharide and mostly present in plants. It is stored in cereals, grains such as wheat and in roots and tubers as in the potatoes. Starch is polysaccharides of glucose. On boiling with water, it form paste. It is consist of structurally two different polysaccharides . Amylose - Water soluble (20%) Amylopectin - Water insoluble (80%) Both compound gives glucose on hydrolysis. Starch Dextrin Maltose Glucose

5. Amylose consist of linear, long unbranched chain of 300-400 α- glucose units forming a helical structure linked by α-1,4- glycosidic bond. Amylopectin contain more than 1000 α-glucose units in a highly branched structure with 24-30 glucose unit per branch. The branching occur through α-1,6- glycosidic bond. Starch dissolved in hot water and gives blue color with iodine. Starch is one of the important carbohydrate in human diet. It is easily hydrolysed by enzyme amylase to smaller units called dextrins and then to maltose and completely to glucose.

6. α-1,6- glycosidic bond α-1,4- glycosidic bond STARCH

7. GLYCOGEN Glycogen is storage polysaccharides of animal cells. It is also called as animal starch. It is found in liver cells, muscles cells and brain. Glycogen also found in plant cells. It is synthesized and stored in muscles and liver and later it is break down to glucose. It is more branched and compact than starch. It is made up of glucose units linked by 1,4 linkage and branches linked by 1,6 linkage. In tissues, glycogen present in the form of granules. It gives red colour with iodine.

8. CELLULOSE Cellulose is the most important structural component of plant cell wall. It is also found in some micro-organisms, and it does not occur in animal body. It provides shape, protection, and support to cells, tissue or organ. Wood, cotton is made up of cellulose. Cellulose is fibrous, tough and water insoluble substances. It is linear, unbranched , homo-polysaccharide of 10000 or more D- glucose linked by β-1,4 glycosidic bond. It gives no colour with iodine. It is highly resistant to acid hydrolysis. It is non- digestable .

9. Cellulose

10. AGAR Agar is a galactan made up of sulphated D and L glucose. It is homo polysaccharides present in sea weeds. Agar  is a mixture of two components: the linear polysaccharide agarose , and a heterogeneous mixture of smaller molecules called agaropectin . It forms the supporting structure in the cell walls of certain species of red algae. It dissolve in hot water and set to gel form on cooling. It is used as culture media for bacteria and also in treatment of constipation.

11. Agar Agarose Agropectin

12. HETERO POLYSACCHARIDES These are complex polysaccharides. It is composed of monosaccharides or their derivatives. It is also known as hetero glycans . It is usually present with non carbohydrate material such as protein, lipid etc. There are various types of hetero polysaccharides. Mucopolysaccharides Proteoglycans Glycoproteins Lipopolysaccharides

13. 1. MUCOPOLYSACCHARIDES They are made up of repeating unit of amino sugars and uronic acids. Acetylated amino group, sulphate groups and carboxyl group are present in it. It is also known as Glucosaminoglycans (GAG). It is essential component of tissue structure such as cartilage, skin tendons, collagen and elastin fibres . Example: Heparin Hyaluronic acid Chondroitin Keratan sulphate

14. HEPARIN Heparin is a anticoagulant agent. It prevent blood clotting in blood, liver, lungs, kidney, spleen etc. It is composed of alternating units of N- supho D- Glucosamine-6-sulphate and Glucuronate - 2-sulphate. It is polymer of glucuronic acid and N- acetylglucosamine . It is mainly occur in intracellular granules of basophill cells and mast cells. It is also used before surgery to reduce the risk of blood clots.

15. 2. PROTEOGLYCANS They are high molecular weight substances. They contains large amount of mucopolysaccharides and proteins. They are also called as mucoproteins or mucoids . They form ground substance in extracellular matrix of connective tissue and act as supporting elements. The combination of proteoglycans and collagen form cartilage. They are also involved in binding  cations  (such as sodium, potassium and calcium) and water, and also regulating the movement of molecules through the matrix.

16. 3. GLYCOPROTEINS When conjugated proteins are covalently linked with carbohydrate, they are called as glycoproteins . They mainly contain N- acetylneuranic acid (NANA). Other carbohydrates such as mannose, galactose , N- acetyl glucosamine and N- acetyl galactosamine are present in glycoproteins . It is widely distributed in cells and perform various function such as hormones, transport proteins, structural proteins, receptors, enzymes etc. Cell to cell surface adhesion is done by receptors glycoproteins .

17. 4. PEPTIDOGLYCAN Peptidoglycan is a long polysaccharide made up of disaccharides contain N- acetyl glucosamine and N- acetyl muramic acid. They are joined together by β-1,4 glycosidic bond. It is present in bacterial cell wall. The biosynthesis of peptidoglycan is carried out by several enzymes. The function of these enzymes is inhibited by certain antibiotics such as penicillin. Penicillin inhibit the production of peptidoglycan .

18. FUNCTION OF POLYSACCHARIDE Polysaccharides are used for storing energy, some for sending cellular messages, and others for providing support to cells and tissues. Starch and glycogen are the major storage food of organic world. On hydrolysis storage carbohydrates provide both energy and carbon chains. Chitin is the structural carbohydrate of fungal walls and exoskeleton of arthropods. Cellulose is the structural substance of cell walls in most of the plants.

19. Mucilage present as a protective coating around aquatic plants, bacteria, blue-green algae etc., is derived from polysaccharides. Mucopolysaccharides present inside human body are keratin sulphate , chondroitin sulphate and hyaluronic acid. They have several functions - lubrication of ligaments and tendons, providing strength and flexibility to skin etc. Heparin prevents blood clotting inside blood vessels of animals. Pectins are commercial jellying agents.