Week # 7 Carbohydrates
Lectures # 18, 19
Concepts:
Recognize various types of carbohydrates including monosaccharides,
disaccharides, polysaccharides, hexose, pentose, aldose, ketose.
Recognize the structures of the above with alpha and beta
Recognnize hemiacetal and acetal functional groups in the various saccharides
Ques. 1. List 3 disaccharides and list the monosaccharides present in each.
Ques. 2. List 3 polysaccharides and state where they can be found in nature.
Ques. 3. Which hexose is also a ketose?
Ques. 4. For the two structures below:
CH2OH
H
O OH
H
OH H
H
HO
H OH
CH2OH
HO
OH
H
OH H
OH
H
H OH
a. Identify glucose and galactose.
b. Identify the alpha and beta hemiacetal OH's.
Review: Combination Reactions
14. Hemiactal Synthesis
Alcohol + aldehyde or
ketone
 hemiacetal
Make a ring:
4-hydroxypentanol
15. Acetal Synthesis
(ether synthesis)
Alcohol + hemiactal
 acetal + water
Above hemiacetal with
ethanol
Ques. 5; Identify the alpha and beta glucose and the alpha and beta galactose in
the structures above.
Ques. 6: a. Which structure is alpha ………and beta fructose?
b. Which structure A or C is a aldose ………and a pentose?
c. Which structure B or D is a ketose ………and a hexose?
Ques. 7. Write the complete synthesis reaction starting with the monosaccarides
for the formation of:
maltose
sucrose
Ques. 8: a. Which structure is maltose? And which is lactose?
b. Which arrow letter points to an alpha acetal or glycosidic bond?
c. Which arrow letter points to an beta acetal or glycosidic bond?
d. Which arrow letter points to an alpha anomeric carbon?
anomeric carbon?
… an alpha
Ques. 9: a. Which structure is sucrose?
… fructose?
b. Which structure is glucose?
c. Which arrow letter points to a alpha acetal or glycosidic bond?
d. Which arrow letter points to a beta anomeric carbon?
Ques. 10. List the di- or polysaccharides with alpha - acetal linkages. Same for
beta - acetal linkages.
Ques. 11. What are the differences and similarities for starch, glycogen, and
cellulose.
Ques. 12.
H
CH2 OH
O H
H
OH H
OH
B
A
#4
#1
OH
OH
H
H
OH
#2
CH2 OH
O
H
OH H
H
H
CH2 OH
O OH
H
OH H
O
H
H
OH
#5
H
OH
CH2 OH
H
O
H OH
OH
CH2 OH
OH
H
H
CH2 OH
OH
H
D
O
#3
H
H
C
OH
OH
a. The common names for structures A, B, C, are abd give the reason for
your choices:
A=
B=
C=
b. Which structure(s) is a hexose?
c. List the arrow numbers which point to alpha OH anomeric carbons.
d. List the arrow numbers which point to beta OH anomeric carbons.
e. List the arrow numbers which point to beta acetal linkages.
f. Put a circle around ALL hemiacetal groups in ALL structures.
g. Which structure is a ketose?
A pentose?