Gumdrop Macromolecules Modeling Activity
Background:
Understanding the arrangement of atoms within nutrient molecules often helps explain their chemical behavior, health
attributes and role in weight balance. Although atomic representations do not accurately represent electron
configurations, they can be used to show the arrangement of nuclei and bond type. In the following activities, you’ll
construct several different molecular models that represent substances that play an essential role in our nutritional
needs.
Purpose: Write the purpose of this activity on your lab paper.
Materials:
Gumdrops of various colors
Toothpicks
Use a ruler and draw the Molecules of Life Table into your lab notebook.
Teacher initials: ___________
Part 1: Carbohydrates (work in a group of 2/3)
Carbohydrates are a group of nutrients that include sugars and starches. The main function of carbohydrates is to
provide a source of short-term energy. Perhaps, the most familiar group of carbohydrate, or building block, is glucose.
Glucose is a monosaccharide, which means that it is a one (monomer) sugar unit. Monosaccharides can be joined
together to produce polymers, or larger chains, of carbohydrates. Starch is an example of a polymer, consisting of a
long chain of simple sugar molecules that are linked together. In this set of activities, you’ll construct a monomer unit
or simple sugar (glucose) and observe the effects of a dehydration synthesis reaction.
(Suffix and Prefix -below)
Mono - one
Di - two
Poly - many
Sacchar-sugar
ose – sugar
Mer – unit or part
Carbohydrate Pre-Lab Questions: Answer these questions on your lab paper using complete sentences.
1. What is the function of carbohydrates?
2. What is the main group (monomer) of carbohydrate?
3. Define the term monomer and provide an example of a carbohydrate monomer. Use the suffixes and prefixes
above
4. Define the term polymer and provide an example of a carbohydrate polymer. Use the suffixes and prefixes
above
Follow the directions on the procedure page to build a carbohydrate monomer.
Teacher initials: ___________
Follow the directions on the procedure page to Model Dehydration Synthesis.
Teacher initials: ___________
Answer the Carbohydrate Analysis Questions below in your lab notebook.
Analysis Part 1: Answer these questions in complete sentences on your lab paper.
1. What are the three major elements found in every carbohydrate?
2. What type of molecule is removed during dehydration synthesis? How did it form?
3. How is glucose related to larger carbohydrates?
4. A starch molecule consists of countless monosaccharide simple sugars that have bonded together by
dehydration synthesis. What might happen if you added water to a starch molecule? Justify your answer.
Part 2: Proteins (Working in groups of 2)
Proteins are macromolecules that are found in every living cell. They perform many functions, such as building and
repairing muscle, bone, and hair. They are also found in the cell membrane and help with the transport of materials
into the cell. Special proteins, called enzymes, catalyze chemical reactions. Like carbohydrates, proteins form a critical
part of our diet. The basic monomer unit, or building block, of a protein molecule is an amino acid. All amino acids have
the following parts:
Amine (NH2) group
Carboxyl (COOH) group
“R” group (different for each of the 20 amino acids)
Protein Pre-Lab Questions Answer these questions on your lab paper using complete sentences.
1. What are the functions of proteins?
2. What is the monomer unit of a protein?
Follow the directions on the procedure page to build a protein monomer.
Teacher Initials _________
Analysis Part 2: Answer these questions in complete sentences on your lab paper.
1. What major elements are found in every protein?
2. How are amino acids related to proteins?
3. From what you can observe in the molecular structure, can dehydration synthesis also produce long chains of
amino acids? Explain.
Part 3: Lipids
Lipids include substances such as waxes, oils, and fats. One function of lipids is for long-term energy storage. Lipids also
make up the chief part of the cell membrane, and provide insulation in organisms. They are made of a monomer unit,
called a fatty acid, bonded to another monomer unit, called a glycerol.
Although you may not know what they are, chances are you’ve heard of saturated and unsaturated fats. Fats and waxes
are examples of lipid polymers. They are long molecules that can have more than 20 carbon atoms in their backbone. A
saturated fat has only single bonds in its carbon backbone. An unsaturated fat has one or more double bonds.
Lip Pre-Lab Questions: Answer these questions on your lab paper using complete sentences.
1. What are the main types of lipids?
2. What are the functions of lipids?
3. What are the monomer units of a lipid?
4. What are the polymer units of a lipid?
Follow the directions on the procedure page to build a Lipid molecule.
Teacher Initials _________
Analysis Part 3: Answer these questions in complete sentences on your lab paper.
1. What major elements are found in every lipid?
2. When saturated, to how many different atoms can a carbon bond?
3. What must be added to an unsaturated chain, in order to make it saturated?
4. Infer the structural feature of a “polyunsaturated fat.” Explain what it would look like.
Conclusion: Using the CER model, write a conclusion for the following question: How can you determine if a
structural or chemical formula is a biological molecule?
Gum Drop Lab Procedures
Key for Gumdrops
H – Yellow or white
N- Orange
O – Purple
C – Red
Toothpick = chemical bond
Bonding Rules:
Carbon = 4 bonds always
Oxygen = 2 bonds always
Hydrogen = only 1 bond
Nitrogen = 3 bonds always
Procedure: Carbohydrate Monomer - Glucose Model
1. Examine the gumdrops that you will be using to assemble your molecular models. Now, consider the formula of
glucose, C6H12O6. Based on this formula, determine how you should assign specific colors to the component
atoms. (The most common color should be assigned to hydrogen, since hydrogen atoms are the most
numerous.)
2. To build the ring version of glucose, construct a closed ring formed by five carbon
atoms and one oxygen atom.
3.
Add the sixth carbon atom. It is attached to the ring carbon that is immediately to
the left of the oxygen atom.
4. The remaining five oxygen atoms are part of hydroxyl (OH) groups. They are added
as shown here.
5. Finish the model by adding the remaining seven hydrogen atoms so that each carbon atom forms four bonds.
6. Identify and cut out three carbohydrate monomers from the Molecules of Life Model page and glue them into
the Molecules of Life Data Table you drew into your lab notebook.
Modeling Dehydration Synthesis: (2 groups of two or three, combine your glucose molecules)
To produce larger carbohydrate molecules, glucose is linked to other simple sugar molecules. During this bonding
process, two atoms of hydrogen and one atom of oxygen are removed from the linking sugars. These atoms join
together to produce a molecule of water. Hence, this type of sugar bonding is called dehydration synthesis.
1. Construct a second model of glucose.
2. Place both models side-by-side. Remove the two hydrogen atoms and one oxygen atom that are associated with
dehydration synthesis (identified by the dashed line.)
3. Join the free bond of the ring oxygen atom to the free bond of the carbon atom. Join the three removed atoms
together to form a water molecule.
Procedure: Amino Acid Model
1. Glycine is the simplest structural amino acid. Like all amino acids, it has an amine
group. Use gumdrops to construct this functional group.
(NH2)
2. Like all amino acids, glycine also has a carboxyl (COOH) group. Use gumdrops to
construct this functional group. Remember to retain consistency in your
assignment of gumdrop colors.
3. The amine and acid group are both attached to a central carbon atom. The remaining two bonds of this
backbone carbon are saturated with hydrogen. Your finished glycine model should resemble this image.
4. Identify and cut and paste the proper protein diagrams monomers from the Molecules of Life Model page and
glue them into the Molecules of Life Data Table you drew into your lab notebook.
Lipids
Procedure: Lipid Model (Saturated and Unsaturated Fats)
1. Construct a chain of four carbon atoms.
2. Add two hydrogen atoms to each carbon atom. Place a toothpick at both ends of the chain to represent the
bond that connects this section to the rest of the fat molecule.
3. Now, construct a version of this carbon backbone that contains an unsaturated carbon.
5. Identify and cut and paste the proper lipid diagrams from the Molecules of Life Model page and glue them
into the Molecules of Life Data Table you drew into your lab notebook.
Conclusion: Complete the conclusion using the CER (Claim, Evidence, and Reasoning) method in your lab journal.