1 / 17

Disaccharides

Disaccharides. Disaccharides. 3 main disaccharides-sucrose maltose lactose All are isomers with molecular formula C 12 H 22 O 11 . On hydrolysis they yield 2 monosaccharide. Soluble in water

virginie
Download Presentation

Disaccharides

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Disaccharides

  2. Disaccharides • 3 main disaccharides-sucrose maltose lactose • All are isomers with molecular formula C12H22O11. • On hydrolysis they yield 2 monosaccharide. • Soluble in water • Even though they are soluble in water, they are too large to pass through the cell membrane.

  3. Structure of Disaccharides. • Formed by combination of 2 monosaccharides. • Bonds between 2 monosaccharide are known as Glycosidic bond. • Consider a combination of a molecule of alpha –glucose and a molecule of beta glucose, the product is a beta maltose and water.

  4. Formation of maltose

  5. Glycosidic linkage between glucose.

  6. Fermentation • Sucrose and maltose will ferment when yeast is added because yeast contains the enzyme sucrase and maltase. • Lactose will not ferment because yeast does not contain lactase.

  7. Testing for disaccharides • The chemical reactions of these sugars can be used to distinguish them in the laboratory. • If you have 2 test tubes containing a disaccharide,C12H22O11.To determine if it is sucrose lactose or maltose. • We can use the alkaline Cu complex reaction of glucose and the principle of fermentation.

  8. Sucrose • Is a sugar used at home • Also known as the cane sugar • When hydrolyzed, it forms a mixture of glucose and fructose.

  9. Maltose • Commonly known as malt sugar. • Present in germinating grain • Produced commercially by hydrolysis of starch.

  10. Lactose • Commercially known as milk sugar. • Of animal origin • Bacteria cause fermentation of lactose forming lactic acid. • When these reaction occur ,it changes the taste to a sour one.

  11. Formation of sucrose.

  12. 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 (C6H10O5)x

  13. Polysaccharides • The hexosans have the general formula (C6H10O5)x. • Where x is a large number. • Some of the common hexosans are starch, cellulose and dextrin.

  14. Starch • Insoluble in water • Gives a characteristic blue colour with iodine. • Test is used to determine the presence of starch in any solution or even to test for iodine.

  15. Cellulose • Wood, cotton and paper are composed primarily of cellulose.

  16. 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.

  17. Heparin • Is a polysaccharide used as blood anticoagulant. • It accelerates the inactivation of thrombin and other blood-clotting agents • It’s the strongest organic acid found in the body • Other polysaccharides are Dextran and Heparin.

More Related