carbo review - Carbohydrates Know the general features and...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Carbohydrates Know the general features and roles of carbohydrate molecules • At least one, often more, asymmetric (chiral) centers • Linear and ring structures • Can form polymers through  glycosidic  bonds • Can form multiple hydrogen bonds with water and other molecules Major form of stored energy Know the difference between aldoses and ketoses •  Aldoses  are monosaccharides that contain an aldehyde function. The simplest aldose is glyceraldehyde, which has two stereoisomers •  Ketoses  contain a ketone group, the simplest is dihydroxy-acetone Understand how the D/L designation of sugars is derived • The D/L designation refers to the configuration of the highest numbered asymmetric carbon, that is the one furthest from the carbonyl carbon • The isomer is D if the hydroxyl group on the highest numbered carbon is drawn on the right in a flat projection • Most naturally occurring carbohydrates are D isomers Understand how linear forms can cyclize to form a pyranose or a furanose The alcohol group of a carbohydrate can react with the aldehyde or ketone function to form a hemiacetal, this results in cyclization of the linear sugar, and generates an additional asymmetric center. The result is a six- or fivemembered ring containing oxygen, called a  pyranose  or a furanose • In aqueous solution, the pyranose and furanose are the preferred forms of monosaccharides Cyclized forms may have 2 stereoisomers called anomers • Cyclization of D-glucose generates a mixture of  α and ß isomers (called  anomers ) Pyranoses typically adopt chair or boat configurations Sugars can be derivatized to form sugar alcohols, deoxy sugars, and so on Monosaccharides can be converted to numerous derivatives: sugar acids, sugar alcohols, deoxy sugars, sugar esters, amino sugars, phospho sugars Elimination of water forms α or ß glycosidic bond Know some examples of disaccharides Cellobiose and maltose are of reducing. Sucrose and trehalose are of non-reducing.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Starch is a polymer of amylose and amylopectin containing both 1,4 and 1,6 glycosidic bonds •  Amylose  is a linear chain of glucose units in  1,4 linkages
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/08/2012 for the course CHEM 3361 taught by Professor Marsh during the Spring '11 term at University of Texas at Dallas, Richardson.

Page1 / 5

carbo review - Carbohydrates Know the general features and...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online