IB EDIBLE MOLECULE LAB
Organic compounds contain carbon and often come from living organisms. There are four main
types of organic compounds; proteins, lipids, carbohydrates, and nucleic acids. While each of
these macromolecules has many functions we usually focus on what their primary functions.
Proteins are often considered the building materials of life. One of lipids many jobs are to store
energy. Carbohydrates are often used for immediate energy consumption. Lastly, nucleic acids
contain the blue prints to all life.
AIM: To make organic molecules models from edible objects.
To simulate condensation (dehydration synthesis) and hydrolysis reactions using
models.
STEP 1: Your first task is to construct and monosaccharide molecule, an amino acid molecule
and glycerol molecule. In your lab book write out a brief procedure and key to how you are
going to construct your molecules using the cereals, marshmallows and toothpicks provided.
Use your text book to help guide the construction the molecules. You can have one key for all
three molecules you are making. (Remember you have some double bonds in these molecules)
STEP 2: Once you have completed your procedure and key construct all three molecules.
Sketch out each molecule and leave a place for me to sign off that you have completed each
model correctly.
STEP 3: Once you have completed your three monomers your next step is to combine your
molecules into polymers. Organize yourself into a group of three and come up with a method to
combine your three monosacharides into a disaccharide and then into a polysaccharide. Use
your textbook and notes to guide the process. Remember what type of reaction this is! Sketch
out the process in your lab book. (You only need to have a sketch of the two monosacharides
combing to form a disaccharide.) Remember to get my signature for verification you have
completed the process.
STEP 4: In the same group of three combine your amino acids into a dipeptide and then a
polypeptide. Use your textbook and notes to help guide the process. Remember what type
reaction this is! Sketch out the process in your lab book and get my signature for verification.
(you only need to sketch out the process of forming the dipeptide)
STEP 5: Your last task is to make a triglyceride molecule. Each person in your group of three
needs to make a fatty acid chain with 4 carbon molecules. Use your notes and textbook to guide
this process. When you have completed this task you will need to put the three fatty acids and
one of your glycerol molecules together to form a lipid. When you have completed this process
sketch it in your lab book and get my signature.
CONCLUSION: In your lab book write an IB level Conclusion using your lab matrix. Some
questions to consider are provided below. Pay particular attention to CE column 1 and 2
1. What is the formula for a monosaccharide?
2. Compare and contrast condensation reactions (dehydration synthesis) with hydrolysis?
What is it relationship in this lab to forming macromolecules? Include examples.
3. What is an organic compound? What are the three elements found in all the three
molecules you constructed?
4. How many bonds can a carbon atom form? Why is this so important?
Teacher Notes
Each student is provided a copy of the lab a couple of days ahead of time to complete step 1
before the class. You will need OK their procedures and key before they can get started. When I
hand out the lab I provide them with a list materials.
Materials:
Toothpicks
Marshmallows (Little hot cocoa ones! Big ones are too big!)
Coco puffs
Yellow Kix
Fruit Loops
The fruit loops can be used for various molecules because of their color. One problem you will
run across is different student will use different things to represent different molecules i.e. one
will choose marshmallows for carbon and another will choose coco puffs. It is up to you as a
teacher to decide how to deal with this. Another problem is student trying to determine what
they want to use to represent the free radicle on the amino acid. One method I have used is to
give the student a gum drop and tell them that represents the R group. If you have a more
advance group have them figure it out. Most end up using one of the fruit loops. I generally do
this lab after taking notes with them and sketching out the molecule shapes during notes. It is
quite a difficult concept for some to create their own models. It can be frustrating too because
the toothpicks and cereal don’t always cooperate. Students do end up like the lab and really
understand the bonding process.