Ch. 8: Simple Carbohydrates Flashcards
Types of CHO (classification)?
Monosaccharides
Disaccharides
Oligosaccharides: 2-10 monosaccharides
Polysaccharides (glycans): > 10 monosaccharides
Classification of CHO: aldoses vs. ketoses?
Aldose: contains reactive aldehyde group
Ketose: contains reactive ketone group
3 C CHOs?
D-glycerose (D-glyceraldehyde)
D-erythrose
5 C CHOs?
D-lyxose
D-xylose
D-arabinose
D-ribose
Examples of aldoses?
D-galactose
D-mannose
D-glucose
Examples of ketoses?
Dihydroxyacetone D-xylulose D-ribulose D-fructose D-sedoheptulose
What types of sugar linkages can humans digest? Can’t digest?
Can digest: alpha-linkage
Can’t digest: beta-linkage
How to determine D & L sugars?
Config of asymmetric C farthest from CHO or C=O
L: OH on left
D: OH on right
What are stereoisomers?
Same chemical formula
Different position of OH on 1 or more asymmetric Cs
What are enantiomers?
Stereoisomers that are mirror images
What are epimers?
Stereoisomers w/different position of OH at only 1 asymmetric C
How to differ between alpha and beta config of CHOs in ring structure?
OH group on anomeric C
Alpha: OH on right (Fischer projection), BELOW ring
Beta: OH on left (Fischer projection), ABOVE ring
Alpha & beta D-glucose: which is more stable?
Beta-D-glucose (majority in water)
What is the major form of fructose? Differs in what situation?
Beta-D-fructopyranose (6 membered ring)
When phosphorylated, forms 5 membered ring (furanose)
CHO derivatives: sugar alcohols ➡️ describe?
Examples?
Carbonyl group reduced to OH group
Glycerol
D-sorbitol
CHO derivatives: sugar acids ➡️ describe?
Examples?
Carbonyl or OH group oxidized to COOH group
D-gluconate
Ascorbic acid
CHO derivatives: amino sugars ➡️ describe?
Examples?
Replace a OH group w/NH2 group
D-glucosamine
D-galactosamine
CHO derivatives: sugar phosphates ➡️ describe?
Examples?
Phosphoric esters of CHOs
Glucose-6-P
Ribose-5-P
CHO derivatives: deoxy sugars ➡️ describe?
Examples?
1 or more OH groups of pyranose or furanose substituted w/H
2-deoxy-alpha-D-ribose
Alpha-L-fucose
CHO derivatives: glycosides ➡️ describe?
Examples?
Condensation of anomeric OH group w/OH group of 2nd molecule (H2O eliminated)
Streptomycin (antibiotic)
Ouabain (cardiac glycoside)
How are disaccharides formed?
What are the 4 types (& which monosaccharides are they made from)?
2 monosaccharides linked via O-glycosidic bond
Sucrose = Glu + fru Lactose = gal + Glu Maltose = Glu + Glu Lactulose = gal + fru Trehalose Cellobiose
Examples of homopolysaccharides? Important info about each?
Glycogen (animal, alpha(1➡️4 & 1➡️6) links)
Starch: amylose, amylopectin (plants, alpha(1➡️4 & 1➡️6) links)
Cellulose (beta(1➡️4) links)
Chitin (N-acetylglucosamine polymer)
Examples of heteropolysaccharides?
Proteoglycan (polysaccharide + protein)
Glycosphingolipids (polysaccharide + lipids)
