chapter 7.1: monosaccharides and disaccharides chem 7784 biochemistry professor bensley
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Chapter 7.1: Monosaccharides and
Disaccharides
CHEM 7784
Biochemistry
Professor Bensley
CHAPTER 7.1 Monosaccharides and Disaccharides
– Structures and names of monosaccharides– Open-chain and ring forms of monosaccharides– Structures and properties of disaccharides
Today’s Objectives: (To learn and understand the)
Aldoses and KetosesAn aldose contains an aldehyde functional group
A ketose contains a ketone functional group
Enantiomers
• D-glucose and L-glucose are ENANTIOMERS: non-superimposable COMPLETE mirror images (differ in configuration at EVERY CHIRAL CENTER).
Diastereomers
D-Threose D-Erythrose
Epimers
• Epimers are two sugars that differ only in the configuration around one carbon atom
Structures to Know• Ribose is the standard five-carbon sugar• Glucose is the standard six-carbon sugar• Galactose is an epimer of glucose• Mannose is an epimer of glucose• Fructose is the ketose form of glucose
D-Ribose D-Glucose D-Galactose D-Mannose D-Fructose
Hemiacetals and Hemiketals
Cyclization of Mono- saccharides
Pyranoses and Furanoses
Chain-ring Equilibrium and Reducing Sugars
Important Hexose Derivatives
The Glycosidic
Bond
Nonreducing Disaccharides
• Two sugar molecules can be also joined via
a glycosidic bond between two anomeric
carbons • The product has two acetal groups and no
hemiacetals• There are no reducing ends, this is a
nonreducing disaccharide• Examples: Sucrose and Trehalose
(structures on next slide)
Common Disaccharides
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