Name ___________________________________________
Date __________________
Protein Model Lab
Carbohydrates, lipids, proteins and nucleic acids are the four major groups of organic compounds found in
living organisms. Today, you will model the important class or organic compounds, known as proteins. They
are the main structural and growth component of cells in tissues such as skin, hair, muscle and blood. Other
proteins serve as enzymes to break down organic polymers or hormones that act as chemical messengers for the
body. Proteins contain the elements, carbon, hydrogen, oxygen, nitrogen and sometimes sulfur.
The monomer, amino acid, is the basic structural unit of all proteins. There are only 20 amino acids known to
exist in proteins, all with the same basic structure.
**In the space below, make a diagram of a basic amino acid. To your diagram, label the amino group (-NH2),
the carboxyl (acid) group (-COOH) and the radical group (R).
Procedure:
A. Examine the three amino acids shown in the figures below. To each amino acid:
a. Color the amino group BLUE
b. Color the carboxyl (acid) group RED
c. Color the radical group YELLOW
d. Color the middle carbon and the hydrogen off of the carbon, PURPLE
Glycine
Alanine
Threonine
B. Working in pairs, you will construct each of the amino acids on the page before this. After completing
all three models, you will need to show your teacher all three.
1. What part of the amino acids differed from molecule to molecule? ________________________
2. What three (3) parts remained the same in all three amino acids?
A protein is formed by the chemical bonding of many amino acid molecules. Proteins may contain as few as 50
or as many as 5000 or more amino acids. When amino acids bind with other amino acids, they bind through the
process of Dehydration Synthesis with the loss of water. Two amino acids binding together is called a
dipeptide and bind at a special bond called a peptide bond. Three or more amino acids together is known as a
polypeptide.
C. You and your partner will now combine a Glycine molecule with an Alanine molecule and undergo
dehydration synthesis. To do this, line them up as Glycine and then Alanine on your desk. To the
Glycine on the left, remove the –OH off of the carboxyl group. To the Alanine on the right, remove an
–H from the amino group. Put the three atoms together to form a water molecule and then bind the C to
the N. This C-N bond is the peptide bond. You have now made a dipeptide! Get it signed!
+
3.
4.
5.
6.
7.
What process joined the two amino acids together? _________________________________________
What is the general name of the protein you have now formed? _______________________________
What needed to be removed in order to join the two amino acids together? _______________________
What is the name of the special C-N bond between the two amino acids? ________________________
If you bonded all three of your amino acid molecules together, how many water molecules would you
need to remove? _________________
8. If all the amino acid molecules in the class were bonded together, we would now call this a
_________________________________.
9. What elements are found making up proteins? _____________________________________________
10. Discuss the function of amino acids in our bodies.