Biochemistry Packet
Part 2: Carbohydrates
Directions: Using chapter 24 in the Chemistry 1 book to answer the following questions about
carbohydrates
1. Define monosaccharide
Simple sugar, simplest carbohydrate
2. List structural features of a monosaccharide:
a. 5-6 carbons
b. carbonyl
c. hydroxyl
3. 3 monosaccharides are shown in fig 24.8. Write their molecular and empirical formula.
Glucose: molecular : C6H12O6 empirical CH2O
Fructose: Same
Galactose: Same
All carbohydrates have the empirical formula CH2O
4. Glucose and fructose are __structural_ isomers
5. Glucose and galactose are called stereoisomers. These are not optical isomers because optical
isomers have only 1 chiral center that is different. Stereoisomers have the same structural
formula but when viewed in 3-D have more than one chiral center that is different. Draw the
cyclic forms of fructose and glucose and circle the chiral centers in each.
OH
H
H
OH H
HO
O
H HO
OH
HO
OH
H
OH
H
OH
OH
OH
Glucose
H
Fructose
6. Draw the straight chain form of glucose below:
H OHH H
O
OHH OHOH OH
7. What functional groups are present in the cyclic glucose but not in the straight-chain?
Cyclic has ether while
8. What functional groups are present in the straight chain glucose but no the cyclic form of
glucose?
Straight chain has aldehyde
9. Disaccharides are formed when two monosaccharide molecules join
a. What kind of reaction is this?
Elimination/condensation
b. What kind of functional group is formed?
ether
10. Important carbohydrates:
Di/polysaccharide
Sucrose
Made from:
Glucose and fructose
lactose
Glucose and Galactose
Starch
Glucose only
11. What is the primary role of carbohydrates in humans?
As an energy source – stored in liver as glycogen