Carbohydrate Structure

Question 1

carbohydrate formula

Answer 1

Question 2

Answer 2

alpha-D-glucose

Question 3

Answer 3

beta-D-glucose

Question 4

Answer 4

beta-D-galactose

Question 5

Answer 5

alpha-D-galactose

Question 6

oligosaccharide

Answer 6

between 2-20 sugar units

Question 7

polysaccharide

Answer 7

> 20 sugar units

Question 8

aldose

Answer 8

C=O at end of chain

Question 9

ketose

Answer 9

C=O in middle of chain

Question 10

triose

Answer 10

3 carbons (glyceraldehyde)

Question 11

4 carbons

Answer 11

tetrose (erythrose)

Question 12

pentose

Answer 12

5 carbons; ribose

Question 13

hexose

Answer 13

6 carbons; glucose

Question 14

all monosaccharides are _

Answer 14

chiral, except dihydroxyacetone

Question 15

enantiomers

Answer 15

non-superimposable mirror images (stereoisomers)

Question 16

pure enantiomer

Answer 16

rotates polarized light

Question 17

Fischer projection

Answer 17

horizontal is toward reader; vertical is away

Question 18

perspective formulas

Answer 18

solid line is toward reader; dash is away from reader

Question 19

Which carbon is designated D or L?

Answer 19

the chiral carbon most distant from the carbonyl group

Question 20

a molecule with _ chiral centers can have _ stereoisomers

Answer 20

n, 2^n

Question 21

epimers

Answer 21

two sugars that differ in stereo configuration at only one carbon position

Question 22

cyclization

Answer 22

intramolecular attack at anomeric C

Question 23

mutarotation

Answer 23

interconversion of alpha and beta anomers

Question 24

6 membered ring

Answer 24

pyranose

Question 25

5 membered ring

Answer 25

furanose

Question 26

alpha-D-sugars

Answer 26

OH down

Question 27

beta-D-sugars

Answer 27

OH up

Question 28

intermolecular attack results in _

Answer 28

di- or polysaccharide

Question 29

formation of a ring

Answer 29

reaction between aldehyde at C1 and hydroxyl at C5 results in hemiacetal --> hemiacetal carbon becomes new chiral center (anomeric carbon)

Question 30

formation of di- or polysaccharide

Answer 30

-OH of glucose molecules condenses with hemiacetal of other glucose molecule --> eliminates H2O --> forms O-glycosidic bond

Question 31

glycosidic bond

Answer 31

between hemiacetal or hemiketal group of a saccharide and -OH of another saccharide

Question 32

all monosaccharides are _

Answer 32

reducing sugars

Question 33

oxidation of anomeric C

Answer 33

CHO to COO-

Question 34

aldehydes can be oxidized to _

Answer 34

carboxylic acids

Question 35

maltose

Answer 35

glucose + glucose with alpha-1,4 bond

Question 36

lactose

Answer 36

glucose + galactose by 1,4-beta bond

Question 37

reducing disaccharides

Answer 37

lactose and maltose

Question 38

non-reducing disaccharides

Answer 38

sucrose, trehalose

Question 39

sucrose

Answer 39

fructose + glucose by beta-2,alpha-1 link

Question 40

trehalose

Answer 40

glucose + glucose with alpha-1,1 linkage

Question 41

proteoglycans, glycoproteins

Answer 41

polysaccharides with protein attachment

Question 42

lipopolysaccharides, glycolipids

Answer 42

polysaccharides attached to lipids

Question 43

polynucleotides

Answer 43

polysaccharides attached to PO4, N-bases

Question 44

glycogen and starch

Answer 44

alpha-1,4 linkage with alpha-1,6 branches; soluble and soft

Question 45

starch polysaccharides

Answer 45

amylose (10-20 percent) and amylopectin (80-90 percent)

Question 46

cellulose

Answer 46

beta-1,4 linkages with no branching; insoluble

Question 47

glycogen

Answer 47

readily accessible source of stored fuel in animal cells

Question 48

glycogen storage

Answer 48

stored in cells of liver and muscles; converted to glucose for energy

Question 49

Why glycogen instead of glucose?

Answer 49

cells would rupture due to osmosis and if [glucose] was always high, it would be hard for cells to uptake glucose when needed

Question 50

glycoprotein

Answer 50

carbohydrate and covalently linked protein; mono-, di-, or polysaccharides

Question 51

proteoglycans

Answer 51

subclass of glycoproteins in which carbohydrates are glycosaminoglycans

Question 52

GAGs

Answer 52

long linear polysaccharides consisting of repeating disaccharide units; contain negatively charged sulfate and carboxylate groups which can bind lots of water

Question 53

bound water in GAGs

Answer 53

gives them lubricant or cushioning properties for their role in cartilage, tendons, heart valves, etc.

Question 54

most important GAGs

Answer 54

hyaluronic acid, dermatan sulfate, chondroitin sulfate, heparin, heparan sulfate, keratan sulfate

Question 55

b-lactam antibiotics (penicillin)

Answer 55

inhibit formation of peptidoglycan cross-links in bacterial cell wall

Question 56

gram-positive bacteria

Answer 56

outer layer is peptidoglycan cell wall

Question 57

gram-negative bacteria

Answer 57

have outer membrane around the cell wall

Question 58

lectins

Answer 58

proteins that recognize and bind to specific oligosaccharide structures

Question 59

glucose and galactose are _

Answer 59

epimers