1 / 11

Glucose

Glucose. Glucose is an abundant and very important monosaccharide. It contains six carbon atoms so it is a hexose sugar. Its general formula is C 6 H 12 O 6.

kfontanez
Download Presentation

Glucose

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. Glucose Glucose is an abundant and very important monosaccharide. It contains six carbon atoms so it is a hexose sugar. Its general formula is C6H12O6. Glucose is the major energy source for most cells. It is highly soluble and is the main form in which carbohydrates are transported around the body of animals. The structure of glucose can be represented in different ways: straight chain ring (simplified) ring

  2. Alpha and beta glucose Glucose exists in different forms called structural isomers. Two common isomers are alpha glucose and beta glucose. 6 6 5 5 alphaglucose betaglucose 4 4 1 1 3 2 3 2 The only difference between these two isomers is the position of the –OH group attached to carbon 1. In alpha glucose it is below the carbon and in beta glucose it is above the carbon. This minor structural difference has a major effect on the biological roles of alpha and beta glucose.

  3. Fructose and galactose Two other important hexose monosaccharides are fructose and galactose. galactose fructose Fructose is very soluble and is the main sugar in fruits and nectar. It is sweeter than glucose. Galactose is not as soluble as glucose and has an important role in the production of glycolipids and glycoproteins.

  4. The formation of disaccharides

  5. DISACCHARIDES Disaccharides are sugars composed of two monosaccharides covalently bonded together by a glycosidic linkage Maltose, also known as malt sugar, is formed from two glucose molecules Lactose, or milk sugar, is a disaccharide formed when the monosaccharides glucose and galactose bond Sucrose is common household sugar and is formed when the monosaccharides glucose and fructose bond MALTOSE = GLUCOSE + ? LACTOSE = GLUCOSE + ? SUCROSE = GLUCOSE + ?

  6. Maltose, sucrose and lactose Maltose (malt sugar) is formed from two glucose molecules joined by an alpha 1–4 glycosidic bond. Sucrose (table sugar) is formed from glucose and fructose joined by an alpha 1–4 glycosidic bond. Lactose (milk sugar) is formed from galactose and glucose joined by a beta 1–4 glycosidic bond.

  7. Benedict’s test for reducing sugars

  8. Benedicts solution is a turquoise liquid containing copper ions and sodium hydroxide; the copper ions exist as Cu2+ in this reagent Chemical Tests for Sugars All the monosaccharides and many of the disaccharides are REDUCING SUGARS Benedict’s test is used to determine the reducing properties of the different sugars If a sugar is a reducing sugar then the Cu2+ ions are reduced to Cu+ which, in the presence of alkaline sodium hydroxide, form copper oxide Copper oxide is insoluble and precipitates out of the solution as a brick-red precipitate

  9. Maltose is a reducing sugar Sucrose is a non-reducing sugar SUCROSE RESULT MALTOSE RESULT Testing for reducing sugars When Benedicts test is performed with the disaccharides maltose and sucrose, the following result is obtained

  10. Testing for a non-reducing sugar • Sucrose is non-reducing so needs a different procedure to the simple Benedict’s test (Benedict’s reagent and heat) • Hydrochloric acid is added and then the mixture is heated (this breaks any bonds between the sugar monomers) • Sodium hydrogencarbonate is added to neutralise (test pH to confirm) • Then proceed with normal Benedict’s test: Benedict’s reagent and heat. • Brick red precipitate is the positive result

  11. Mono- and disaccharides

More Related