Study guide 3

Question 1

Whats the basic formula for saccharides

Answer 1

(CH2O)n where n ≥ 3

Question 2

starch [α

Answer 2

1→4) glucose polymer]

Question 3

What are the functions of carbohydrates?

Answer 3

• metabollic precursors
• energy metabolism and storage
• structural scaffolding for cell walls
• molecular recognition sites

Question 4

Cellulose [β

Answer 4

[β(1→4) glucose polymer]

Question 5

What are some of the chemical features of carbohydrates

Answer 5

linear and ring structures
extensive h-bonding
polymeric structures via glycosidic bonds (can be branched)
one or more chiral centers

Question 6

How many carbon atoms des monosaccharides have

Answer 6

3-7 carbons

Question 7

How is Monosaccharides classifed

Answer 7

number of carbons, nature of carbonyl group

Question 8

What are the 2 carbonyl group in monosaccharides

Answer 8

aldose or ketose

Question 9

Aldoses has how many carbons

Answer 9

more than or equal to 3 Carbons

Question 10

In glucose, out of the 6 carbons, which ones are chiral

Answer 10

4 out of 6, n-2,has 2^ n-2 possible stereoisomers

Question 11

In fructose, out of the 6 carbons how many are chiral

Answer 11

3 of them

Question 12

Which form of monosaccharides are predominately in nature?

Answer 12

D-form sugars are predominate in nature.

Question 13

How are D or L- orientation decieded

Answer 13

by the configurations of -OH at the C farthest from R-CO-R

Question 14

Why are D-from sugars predominately in nature?

Answer 14

sterospecifity of enzymes

Question 15

What are epimers

Answer 15

a pair of stereoisomers, diastereomers

Question 16

Whats true about epimers

Answer 16

has a different configuration at only one of several stereogenic centers.

Question 17

Which aldose stay monomer

Answer 17

glucose

Question 18

The cyclization of sugars happen due to the reaction between

Answer 18

reaction between C5’ alcohol and carbonyl group (most reactive)

Question 19

What is Pyranose derived from

Answer 19

Pyran

Question 20

What is Furanose derived from

Answer 20

furan

Question 21

How many carbons does a Pyranose ring have

Answer 21

6-membered ring

Question 22

How many carbons does a Furanose ring have

Answer 22

5-membered ring

Question 23

How are α and β anomers different from each other?

Answer 23

by the -OH configuration at anomeric carbon (C1 for aldoses; C2 for ketoses

Question 24

What is the anomeric carbon for aldoses

Answer 24

C1

Question 25

What anomeric carbon ketoses

Answer 25

C2`

Question 26

α: −OH and highest carbon on the

Answer 26

opposite side (below the ring)

Question 27

β: −OH and highest carbon on the

Answer 27

same side

Question 28

α and β interconvert spontaneously via

Answer 28

via a linear intermediate (mutarotation)

Question 29

Sugar conformations are

Answer 29

not flat

Question 30

Which is more stable boat or chair conformations

Answer 30

chair is slighlty more stable than boat

Question 31

What are some characteristics of sugar conformation?

Answer 31

sp3 hyb at Cs; 109.5º

Question 32

What are the two sugar conformations

Answer 32

chair and boat conformation

Question 33

Substituents can be located

Answer 33

equatorially or axially

Question 34

Bilk substituents are more stable

Answer 34

equatorially

Question 35

What is a glycosidic bond

Answer 35

a bond at the anomeric carbon

Question 36

Glycosidic bond formation reaction occurs at

Answer 36

OH and anomeric carbon

Question 37

Most polysaccharides have only how many reducing ends

Answer 37

1 reducing end

Question 38

How are disaccharides named

Answer 38

names of monosaccharides involved + linkage type

Question 39

Disaccharides are formed by

Answer 39

forming O-glycosidic bonds between monomers

Question 40

What are the structures of polysaccarades

Answer 40

linear or branched

Question 41

Which polysaccharide has a function of storage?

Answer 41

Starch and Glycogen

Question 42

Which polysaccharide has a function of structure?

Answer 42

Cellulose and chitin

Question 43

Which polysaccharide has a function of bacterial cell wall?

Answer 43

peptidoglycan

Question 44

Recognation happens at the

Answer 44

cell surface

Question 45

Why are polysaccharides needed for storage

Answer 45

keeps all monosacchrides and increases osmotic pressure

Question 46

Osmosis depends on the

Answer 46

number of solute molecules, not the kind

Question 47

Starch is the most

Answer 47

common storage polysaccharides in plants

Question 48

Starch is a mixture of

Answer 48

glucose polymers

Question 49

What is percentage of starch has α-amylose

Answer 49

20-25%

Question 50

α-amylose characterstics

Answer 50

- left hand helix - linear chains of 1000s of units with α(1→4) linkage

Question 51

Amylopectin makes up, what percentage of starch

Answer 51

75-80%

Question 52

Amylopectin characterstics

Answer 52

- liner chains with α(1→4) linkage AND branches at every 24-30 residues with α(1→6) - 2x10 3 - 2x10 5 glucose units (largest polymers in nature) α(1→4)

Question 53

What is in saliva

Answer 53

amylase

Question 54

What is the purpose of amylase in saliva

Answer 54

breaks some α(1→4) bond

Question 55

What is in the small intestines

Answer 55

pancreatic amylase

Question 56

What is in the mixture of pancreatic amylase

Answer 56

mixture of maltose and maltotriose (trisaccharides)

Question 57

α-glucosidase sequentially removes

Answer 57

1 residue at a time at α(1→4)

Question 58

β-glucosidase (debranching enzyme)

Answer 58

cuts α(1→6) linkages and α(1→4).

Question 59

Glycogen is a storage polysaccharide in

Answer 59

animals

Question 60

Where is Glycogen is prevalent where

Answer 60

in the liver (10%) and muscle (1-2%)

Question 61

which one is more branched Glycogen or amylopectin

Answer 61

glycogen every 8-12 residue have α(1→6)

Question 62

Glycogen can be

Answer 62

quickly metabolized and release glucose when blood sugar decreases

Question 63

Glycogen phosphorylase cleaves

Answer 63

α(1→4) from nonreducing end.

Question 64

Glycogen debranching

Answer 64

enzymes attack α(1→6) linkages.

Question 65

Cellulose is the most

Answer 65

abundant natural ipolymer in nature

Question 66

Cellulose role in Plant cell walls

Answer 66

rigidity and mechanical strentgh against osmotic stress

Question 67

How many types of H-bond in cellulose

Answer 67

3

Question 68

What are the 3 types of h-bonding in cellulose

Answer 68

intrastrand, interstrand, and intersheet

Question 69

Why does cellulose have 3 types of h-bonding

Answer 69

very strong, insolube, and resistant to hydrolysis

Question 70

chains in cellulose lie

Answer 70

side by side staggered to form sheets

Question 71

Long linear polymer chain in cellose can be as long

Answer 71

as 15,000 units

Question 72

Where is chitin located in

Answer 72

exoskeleton of crustaceans, insects and spider

Question 73

what are the extended liner chains of chitin made of

Answer 73

N-acetyl-glucosamine (GlcNAc)