Chapter 7- Carbohydrates

Question 1

What are oligosaccharides?

Answer 1

short chains of a few monosaccharide units

Question 2

what are polysaccharides?

Answer 2

long chains of monosaccharide units

Question 3

Monosaccharides have an ______ carbon chain with _____ carbons

Answer 3

unbranched
3-7

Question 4

Monosaccharides are soluble in ____ but not _____

Answer 4

water
nonpolar solvent

Question 5

two families of monosaccharides

Answer 5

aldose
ketose

Question 6

Aldose characteristics

Answer 6

possess a carbonyl at the end of the carbon chain (aldehyde)

Question 7

Ketose characteristics

Answer 7

carbonyl is found at any other position other than the end (is a ketone)

Question 8

Carbons are numbered starting at the extremity closest to _____

Answer 8

carbonyl

Question 9

Monosaccharides contain ________ centers

Answer 9

chiral

Question 10

if there are n chiral centers then there are ____ stereoisomers

Answer 10

2^n

Question 11

If OH on reference carbon is on the right it is known as ____ and in ___ configuration

Answer 11

Dextro
D

Question 12

If OH on reference carbon is on left it is known as ____ and in ___ configuration

Answer 12

levo
L

Question 13

Where is the reference carbon??

Answer 13

chiral carbon most distant from carbonyl

Question 14

Monosaccharides with 5 or more carbons usually occur in solution as _____

Answer 14

cyclic (ring) structures

Question 15

carb rings result from a reaction between ______ and _____

Answer 15

alcohols
aldehydes or ketones

Question 16

An alpha anomer occurs when

Answer 16

OH is on opposite side of the CH2OH

Question 17

A beta anomer occurs when

Answer 17

OH is on same side of the CH2OH

Question 18

A pyranose ring is a

Answer 18

6 membered ring

Question 19

a furanose ring is a

Answer 19

5 membered ring

Question 20

How are hexoaldoses formed

Answer 20

OH on C5 attach C1 carbonyl which forms pyranose ring

Question 21

when Hexoaldoses are formed, C1 becomes chiral making it an _____

Answer 21

anomeric carbon

Question 22

when Hexoaldoses are formed, _____ becomes chiral making it an _____

Answer 22

C1
anomeric carbon

Question 23

when ketohexoses are formed, _____ becomes chiral making it an _____

Answer 23

C2
anomeric carbon

Question 24

How are ketohexoses formed?

Answer 24

OH on C5 attack ketone group on C2 which forms furanose ring

Question 25

(6 member) Fisher to Haworth rules for C2, C3, and C4?

Answer 25

- If OH is right --> down - If OH is left ---> up

Question 26

(6 member) Fisher to Haworth rules for C5?

Answer 26

- If OH is right --> D-sugrar- CH2OH is up - if OH is left ---> L-sugar- CH2OH is down

Question 27

(6 member) Fisher to Haworth rules for C1?

Answer 27

- If alpha anomer has OH --> down (for D) - If Beta anomer has OH ---> up (for D)

Question 28

The position of OH anomeric carbon by convention if alpha, is:

Answer 28

Alpha

Question 29

Pyranose and furanose rings are not ____ but they may assume ______ conformation

Answer 29

planar Boat or chair

Question 30

Boat conformation is _____ stable than chair conformation for pyranose/furanose rings

Answer 30

Less

Question 31

Interconvertion of cyclic a/b anomers in solution occurs via the ______ form

Answer 31

linear

Question 32

Mixtures with pyranose/furanose rings contain a mixture of ______

Answer 32

alpha and beta forms

Question 33

steps of carb ring converting from alpha to beta anomers

Answer 33

- ring opens into linear form - close again to produce other anomer

Question 34

A ______ bond joins monosaccharides to form oligosaccharides

Answer 34

O-glycosidic bond

Question 35

product of O-glycosidic bond forming?

Answer 35

glycoside

Question 36

Since the anomeric OH group is a/b, monosaccharides coming together form:

Answer 36

a or b glycosides

Question 37

Glycosidic bonds result form the _____

Answer 37

condensation with an alcohol other than a sugar.

Question 38

Which OH on the carb rings can form glycosidic bonds?

Answer 38

C1-C5

Question 39

How to know when a sugar is a reducing sugar?

Answer 39

Any sugar counting a hemiacetal

Question 40

Sugars with anomeric carbon not invloved in glycosidic bond are called _____

Answer 40

reducing sugars

Question 41

Characteristics of reducing sugars

Answer 41

- Ring in equilibrium with linear form - contain aldehyde (is reducing agent)

Question 42

When anomeric carbon is involved in glycosidic bond, glycosidic bond renders sugar ____

Answer 42

Non reducing

Question 43

Since the 2 anomeric carbons are involved in glycosidic bonds, Sucrose is not a _____

Answer 43

reducing sugar

Question 44

since the anomeric carbon of glucose is free, lactose is a _____

Answer 44

Reducing sugar