Chemistry of Carbohydrates Lab
Instructions: Students will work in teams of two but will complete their own worksheet. Each team will get a bag of atoms
to put together models of water, and 2 kinds of monosaccharides. See below for the atom color key. Students’ grades will
be dependent on their demonstration of completing the modelling instructions, answering the questions and keeping their
materials and lab space neatly organized.
Model Color Key:
Black = Carbon
Blue= Oxygen
White spherical= Hydrogen
Red= Nitrogen
White tube= bonds
I. Water: The chemical formula for water is H2O. By examining this formula, some information can be gained.
1.
2.
3.
4.
5.
6.
What elements make up water? __________________________________________________________________
What does the subscript 2 following the H represent? _________________________________________________
Why doesn’t the O have a subscript? _______________________________________________________________
How many molecules of water are represented by the formula H2O? _____________________________________
What is the molecular formula of water? ___________________________________________________________
Build the structural model of water and then draw a picture of it.
7. What do the lines between O and H represent? ______________________________________________________
II. Carbohydrates: Saccharides are an important group of biological compounds. The many types of sugars are
grouped into three main categories: monosaccharides, disaccharides, and polysaccharides.
1. Study the structural formulas of the two monosaccharides below.
Glucose:
2. Construct one glucose molecule and one fructose molecule according to the formulas and diagrams.
3. How many Carbon atoms are in a molecule of glucose? _______________ Fructose? _____________
4. What two sugars are being combined to form the disaccharide sucrose? _____________________________
5. Why do they call this a dehydration synthesis? What molecule is given off when the two sugars combine? ______
6. What is the name for a molecule that has 3 or more monosaccharides joined together? _____________________
Structure
Information
CH2OH
CH2OH
CH2OH
O
O
O
O
Starch
CH2OH
O
O
O
OH
O
OH
Cellulose
OH
Found in plants
Used for structure (cell walls)
Glycogen
OH
Found in plants
Energy storage
a.k.a. amylose
Found in animals and fungi
Used for energy
7.
Look at starch and cellulose carefully. How are they different? How are they the same? _______
______________________________________________________________________________
8.
Humans can digest starch and glycogen but not cellulose. Looking at the structural differences, what is
preventing our enzymes from being able to break down cellulose? _______________________
______________________________________________________________________________
9.
10.
Animals can move quickly and plants move slowly. Suggest a reason for the branched structure of glycogen and
the straight structure of starch based on this information. _______________________________
_____________________________________________________________________________
_____________________________________________________________________________
_____________________________________________________________________________
Monosaccharides
Disaccharides
Polysaccharides
Glucose
Sucrose
Amylose
Fructose
Lactose
Cellulose
Look at the table with names of carbohydrates. What is the pattern in the way they are named?
_______________________________________________________________________________
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