Carbohydrates are a versatile class of molecules of the formula (CH2O)n. They are a major form of stored energy in organisms, and they are the metabolic precursors of virtually all other biomolecules. Conjugates of carbohydrates with proteins and lipids perform a variety of functions, including recognition events that are important in cell growth, transformation, and other processes. | Chapter 7 Carbohydrates to accompany Biochemistry, 2/e by Reginald Garrett and Charles Grisham All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt Brace & Company, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 Outline Carbohydrate Nomenclature Monosaccharides Oligosaccharides Polysaccharides Nomenclature Carbohydrates are hydrates of carbon Monosaccharides (simple sugars) cannot be broken down into simpler sugars under mild conditions Oligo = "a few" - usually 2 to 10 Polysaccharides are polymers of the simple sugars Monsaccharides An organic chemistry review Aldoses and ketoses contain aldehyde and ketone functions, respectively Triose, tetrose, etc. denotes number of carbons Aldoses with 3C or more and ketoses with 4C or more are chiral Review Fischer projections and D,L system Stereochemistry Review Read text on p. 210-213 carefully! D,L designation refers to the configuration of the highest-numbered asymmetric center D,L only refers the stereocenter of interest back to D- and L-glyceraldehyde! D,L do not specify the sign of rotation of plane-polarized light! All structures in Figures and are D D-sugars predominate in nature More Stereochemistry Know these definitions Stereoisomers that are mirror images of each other are enantiomers Pairs of isomers that have opposite configurations at one or more chiral centers but are NOT mirror images are diastereomers Any 2 sugars in a row in and are diastereomers Two sugars that differ in configuration at only one chiral center are epimers Cyclic monsaccharide structures and anomeric forms Glucose (an aldose) can cyclize to form a cyclic hemiacetal Fructose (a ketose) can cyclize to form a cyclic hemiketal Cyclic form of glucose is a pyranose Cyclic form of fructose is a furanose Cyclic monsaccharide structures and anomeric forms Cyclic forms possess anomeric carbons For D-sugars, alpha has . | Chapter 7 Carbohydrates to accompany Biochemistry, 2/e by Reginald Garrett and Charles Grisham All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt Brace & Company, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 Outline Carbohydrate Nomenclature Monosaccharides Oligosaccharides Polysaccharides Nomenclature Carbohydrates are hydrates of carbon Monosaccharides (simple sugars) cannot be broken down into simpler sugars under mild conditions Oligo = "a few" - usually 2 to 10 Polysaccharides are polymers of the simple sugars Monsaccharides An organic chemistry review Aldoses and ketoses contain aldehyde and ketone functions, respectively Triose, tetrose, etc. denotes number of carbons Aldoses with 3C or more and ketoses with 4C or more are chiral Review Fischer projections and D,L system Stereochemistry Review Read text on p. 210-213 carefully! D,L designation refers to the .
