ACTIVITY – Building Macromolecules
Name: __________________________
Work in pairs but complete the worksheets individually.
Part A: Carbohydrates
1. Build a model of a water molecule with two hydrogen atoms and one oxygen atom.
a) What is the chemical formula of water? ______________
b) Draw the structural formula of water.
c) What is the ratio of H:O in water? ________
2. Build two models of the monosaccharide glucose as demonstrated using six carbon
atoms, twelve hydrogen atoms and six oxygen atoms.
a) What is the chemical formula of glucose? ___________________
b) Draw the structural formula of glucose.
c) What is the ratio of H:O in glucose? __________
d) Observe the structural formula of the galactose and fructose below.
e) What is the chemical formula of galactose? _________________________
fructose? __________________________
f) What is the ratio of H:O in galactose? _________ fructose? _________
g) How do the ratios of H:O in monosaccharides compare to the ratio in water?
___________________________________________________________
h) An isomer is a molecule that has the same chemical formula as another
molecule but differs in its structural formula. Name one isomer of glucose.
__________________________
3. Observe the two models of glucose on your desk.
a) Find the OH group joined to carbon 1 of one glucose molecule and find the OH
group joined to carbon 4 of the other glucose molecule. What is the name
given to the OH functional group? ___________________________
b) Remove the OH group from the one glucose molecule and the H from the OH
group of the other glucose molecule and connect them. What familiar
compound have you made? _________________
c) Join the two glucose molecules together to form a disaccharide. What is the
name given to this disaccharide? ________________________
d) What is the chemical formula for this disaccharide? ___________________
e) What is the ratio of H:O in this disaccharide? ____________ How does it
compare to monosaccharides and water? ____________________________
f) How is joining two monosaccharides to form a disaccharide an example of a
dehydration synthesis reaction? ____________________________________
______________________________________________________________
4. Bring your disaccharide to the lab bench and connect it to other group’s
disaccharides forming a polysaccharide.
Discussion:
1. The word carbohydrate is derived from carbon and water (hydrate). Explain why this
combination correctly describes this chemical group. ________________________
___________________________________________________________________
___________________________________________________________________
2. If four glucose molecules are joined by dehydration synthesis, how many water
molecules are formed? ____
3. Name the functional group(s) involved in the dehydration synthesis reaction.
___________________________________________________________________
4. Are monosaccharides such as glucose polar molecules? Explain your reasoning.
___________________________________________________________________
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Part B: Fats
1. a) Build the following three molecules; methanol (CH3OH), ethanol (C2H5OH) and
glycerol (C3H8O3).
b) Draw the structural formula of the three molecules below and write the name
beside each one.
c) All three of these molecules are classified as alcohols. All alcohols have a certain
functional group in common. What is the name of that functional group?
_______________________
d) Dismantle the molecules of methanol and ethanol but keep the glycerol molecule.
2. a) Two examples of fatty acid molecules are shown below. Circle and name the
functional group at one end of the molecule.
b) In your group, construct three fatty acid molecules having 4 carbon atoms each.
Draw one of the fatty acid molecules below.
c) A triglyceride fat molecule consists of one glycerol and three fatty acid molecules
joined together by dehydration synthesis. Remove three H from the three OH
groups of the glycerol and an OH from each COOH end of the fatty acids. Join
the three fatty acids to the glycerol backbone. Join each free OH group with
each free H. Draw the triglyceride that you formed below.
Discussion:
1. What elements are found in fats? __________________________________
2. a) What is the chemical formula of the fat you built? ____________________
b) Is the ratio of H:O in fats the same, higher or lower than that found in
carbohydrates? __________________
3. How many water molecules are formed in the formation of a triglyceride fat?
______
4. What is the name of the chemical reaction that forms fats?
___________________________________
5. Is a fat molecule polar or nonpolar? Explain your reasoning.
______________________________________________________________
______________________________________________________________
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Part C: Proteins
Work in pairs.
1. a) One partner will build the amino acid glycine by attaching the following groups to a
central carbon atom using the covalent bond connectors; amino group, carboxyl group,
a hydrogen atom and another hydrogen atom.
b) The other partner will build the amino acid alanine by attaching the following
groups to a central carbon atom; amino group, carboxyl group, hydrogen atom and
methyl group (CH3).
c) Draw both amino acids below and name them.
2. a) What is the chemical formula of glycine? _________________________
b) What is the chemical formula of alanine? _________________________
c) How are the chemical formulas of the two amino acids different? How are they
similar? __________________________________________________________
_________________________________________________________________
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3. Use dehydration synthesis to join the two amino acids you have built by removing an
H atom from the amino group of one amino acid and removing the OH from the carboxyl
group of the other amino acid. Draw the dipeptide you have made in the space below
and label the new peptide bond that has been formed.
4. Connect your dipeptide with those of your classmates using dehydration synthesis to
form a short protein.
Discussion:
1. A protein is a polymer. What is the name given to the monomers?
_________________________________
2. Name the functional groups found in all amino acids that are involved in forming
peptide bonds during dehydration synthesis reactions.
__________________________________________________________________
3. A protein consisting of four amino acids undergoes hydrolysis. How many water
molecules must be broken down and reattached to amino acid molecules during
this process? ___________
4. Calculate the total number of peptides with 10 amino acids that can be formed from
the 20 different types of amino acids. *see page 42 for help
5. What element is present in all amino acids that is not present in most carbohydrates
and lipids? __________________