Ch. 8: Simple Carbohydrates

Question 1

Types of CHO (classification)?

Answer 1

Monosaccharides
Disaccharides
Oligosaccharides: 2-10 monosaccharides
Polysaccharides (glycans): > 10 monosaccharides

Question 2

Classification of CHO: aldoses vs. ketoses?

Answer 2

Aldose: contains reactive aldehyde group

Ketose: contains reactive ketone group

Question 3

3 C CHOs?

Answer 3

D-glycerose (D-glyceraldehyde)

D-erythrose

Question 4

5 C CHOs?

Answer 4

D-lyxose
D-xylose
D-arabinose
D-ribose

Question 5

Examples of aldoses?

Answer 5

D-galactose
D-mannose
D-glucose

Question 6

Examples of ketoses?

Answer 6

Dihydroxyacetone
D-xylulose
D-ribulose
D-fructose
D-sedoheptulose

Question 7

What types of sugar linkages can humans digest? Can’t digest?

Answer 7

Can digest: alpha-linkage

Can’t digest: beta-linkage

Question 8

How to determine D & L sugars?

Answer 8

Config of asymmetric C farthest from CHO or C=O

L: OH on left
D: OH on right

Question 9

What are stereoisomers?

Answer 9

Same chemical formula

Different position of OH on 1 or more asymmetric Cs

Question 10

What are enantiomers?

Answer 10

Stereoisomers that are mirror images

Question 11

What are epimers?

Answer 11

Stereoisomers w/different position of OH at only 1 asymmetric C

Question 12

How to differ between alpha and beta config of CHOs in ring structure?

Answer 12

OH group on anomeric C

Alpha: OH on right (Fischer projection), BELOW ring
Beta: OH on left (Fischer projection), ABOVE ring

Question 13

Alpha & beta D-glucose: which is more stable?

Answer 13

Beta-D-glucose (majority in water)

Question 14

What is the major form of fructose? Differs in what situation?

Answer 14

Beta-D-fructopyranose (6 membered ring)

When phosphorylated, forms 5 membered ring (furanose)

Question 15

CHO derivatives: sugar alcohols ➡️ describe?

Examples?

Answer 15

Carbonyl group reduced to OH group

Glycerol
D-sorbitol

Question 16

CHO derivatives: sugar acids ➡️ describe?

Examples?

Answer 16

Carbonyl or OH group oxidized to COOH group

D-gluconate
Ascorbic acid

Question 17

CHO derivatives: amino sugars ➡️ describe?

Examples?

Answer 17

Replace a OH group w/NH2 group

D-glucosamine
D-galactosamine

Question 18

CHO derivatives: sugar phosphates ➡️ describe?

Examples?

Answer 18

Phosphoric esters of CHOs

Glucose-6-P
Ribose-5-P

Question 19

CHO derivatives: deoxy sugars ➡️ describe?

Examples?

Answer 19

1 or more OH groups of pyranose or furanose substituted w/H

2-deoxy-alpha-D-ribose
Alpha-L-fucose

Question 20

CHO derivatives: glycosides ➡️ describe?

Examples?

Answer 20

Condensation of anomeric OH group w/OH group of 2nd molecule (H2O eliminated)

Streptomycin (antibiotic)
Ouabain (cardiac glycoside)

Question 21

How are disaccharides formed?

What are the 4 types (& which monosaccharides are they made from)?

Answer 21

2 monosaccharides linked via O-glycosidic bond

Sucrose = Glu + fru
Lactose = gal + Glu
Maltose = Glu + Glu
Lactulose = gal + fru 
Trehalose
Cellobiose

Question 22

Examples of homopolysaccharides? Important info about each?

Answer 22

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)

Question 23

Examples of heteropolysaccharides?

Answer 23

Proteoglycan (polysaccharide + protein)

Glycosphingolipids (polysaccharide + lipids)