SBI4U
DATE: _____________________
NAME: _____________________
Building Molecular Models Investigation 1
Problem: How do carbon atoms and other atoms join to form organic molecules?
Materials and Equipment: Molecular model kit
Procedure: Use a molecular model kit and build the molecules indicated in this investigation.
EVALUATION
1. Identify and draw clearly all molecules that you build. Use structural diagrams (not ball and stick or space
filling).
(8 marks)

glucose, maltose, glycerol, fatty acid, triglyceride, glycine, alanine, dipeptide)
2. Identify the various linkages.
(3 marks)

Ether, ester, peptide
3. Identify and label the functional groups on each diagram.
(4 marks)

Carboxyl, carbonyl, hydroxyl, amino
4. Answers to analysis questions to be randomly selected by teacher.
(TBD)
Self Regulation – Pick A, B, or C and complete the prompt.
A- I will reflect on my understanding and seek clarification or assistance when needed by…____________
_____________________________________________________________________________________
B – I will persevere and make an effort when faced with difficult work or concepts by…_______________
______________________________________________________________________________________
C- If something is not going well I will try to figure out why and come up with a new plan by…_________
______________________________________________________________________________________
Pre-lab: Getting ready to use model kits
A. Open the molecular model kits and identify the colours representing carbon (C)_________, hydrogen
(H)______________, oxygen (O)____________, nitrogen (N)___________, and sulfur
(S)______________.
B. How many holes do the following ‘model’ atoms have?
Carbon: ____Oxygen: ____Hydrogen: ____
C. How can a double bond be shown with the model kits?______________________________________
D. Build a molecule of methane, CH4. Is CH4 polar or nonpolar? _______________
Replace one H atom with a C atom and fill any open bonding positions on the C atom with H atoms.
Draw a structural formula, write a chemical formula and name this compound using one of these words:
(methane, ethane, propane, butane, pentane, hexane, heptanes, octane). Is this molecule polar or
nonpolar? ________________
structural formula
chemical formula
name
PART A: Carbohydrates
Glucose has the chemical formula C6H12O6. Build a glucose molecule in cyclic form. (see handout ‘Biological
Molecules’or carbohydrate note from class)
Build another molecule of glucose and join the two molecules together to form maltose. (see handout
‘Carbohydrates’) SHOW YOUR TEACHER YOUR MODEL WHEN YOU ARE DONE!
Analysis - Carbohydrates
1. What features account for carbohydrates high solubility in water?
2. What element forms the bridge between the monomers that make up maltose and sucrose?
3. What molecule was made during the condensation (dehydration synthesis) reactions that formed these
disaccharides?
4. Compare and contrast the overall shapes of cellulose, amylose, and amylopectin.
5. What features of cellulose molecules account for both the strength and the water absorbing qualities of
paper towels?
6. What type of intermolecular force dominate the interactions of carbohydrates and water?
7. Some excess glucose is stored as glycogen in liver and muscle. Why is it helpful that some glucose
supplies are stored as glycogen instead of all being converted to triglycerides (fat)?
PART B: Lipids
Build a glycerol molecule AND build three molecules of a 3 – carbon fatty acid. (see handout ‘lipids’ or lipid
note from class)
Place the glycerol and three fatty acids you built on your table and join them together into a triglyceride by
simulating the process of dehydration synthesis. SHOW YOUR TEACHER YOUR MODEL WHEN YOU
ARE DONE!
Analysis - LIPIDS
1. Compare the shape and molecular structure of saturated and unsaturated fatty acids.
2. What functional groups are involved in the formation of a triglyceride from glycerol and fatty acids?
3. What is the fundamental difference between a triglyceride and a phospholipid?
4. Three fatty acids form a triglyceride with one glycerol. Are carbohydrates and triglycerides both
polymers? Explain.
5. What characteristics of wax make it well suited to the role of nature’s main waterproofing agent?
6. When you consume more food than you require the mitochondria in the liver are involved in forming
triglycerides from the excess. Why is storage of triglycerides important?
PART C: Amino Acids and Proteins
Proteins are made from different combinations of the 20 different amino acids. Remember that all amino acids
contain an amino group and a carboxylic group. Build a model of cysteine AND aspartic acid. (see handout
“Amino acids” and/or note on proteins from class)
Join the amino acids together by simulating the process of dehydration synthesis to create a dipeptide. SHOW
YOUR TEACHER YOUR MODEL WHEN YOU ARE DONE!
Analysis – Amino Acids and Proteins
1. What is the name of the bond that joins the two amino acids together?
2. Compare and contrast the variety of amino acids with that of monosaccharides and fatty acids. Which
group exhibits the greatest structural variability?
3. What special role is played by the amino acid cysteine in tertiary structures?
4. Do all proteins have quaternary structure?
PART D: Nucleic Acids
A nucleic acid is a macromolecule composed of chains of monomeric nucleotides. In biochemistry these
molecules carry genetic information or form structures within cells. The most common nucleic acids are
deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Nucleic acids are universal in living things, as
they are found in all cells and viruses. Nucleic acids were first discovered by Friedrich Miescher in 1871.
Nucleic acids are linear, unbranched polymers of nucleotides.
Each nucleotide consists of three components: a nitrogenous heterocyclic base, which is either a purine or a
pyrimidine; a pentose sugar; and a phosphate group.
Analysis – Nucleic Acids
1. What is the difference between a deoxyribose and a ribose?
2. What is the difference between a purine and a pyrimidine?
3. Describe the structure of ATP.
4. What is the primary function of ATP within living organisms?
5. What bases are building blocks of nucleotides within RNA and DNA, respectively?
6. List some of the structural similarities and differences between RNA and DNA.
7. How are bases paired within the DNA double helix?
8. What type of bonding is responsible for the forces maintaining these base pairings and the double helix?
PART E: Advanced Analysis
1. Create a straight chained hydrocarbon containing six carbon atoms and 14 hydrogen atoms, which is
hexane, C6H14.
2. Build another hexane molecule and place it alongside the first one you built. If you do not have enough
pieces to build a second, then join up with a partner.
a) What type of intermolecular forces hold hexane molecules to each other? (see note from start of
year)
3. Convert one of the terminal methylene groups (-CH3) on each molecule into a carboxyl.
b) What type of biomolecule have you created? (see note on lipids)
4. Orient the two molecules so that portions of the molecules that would normally form intermolecular
bonds lie next to each other.
c) What intermolecular forces help to hold these molecules together?
5. Remove an H atom from the third C and the fourth C of one molecule. Replace these atoms with a long
spring, forming a double bond between these carbon atoms.
d) Describe the change in the overall shape of the molecule caused by the introduction of a
carbon-carbon double bond.
6. Keeping the carboxyl groups as close to one another as possible, orient the molecules parallel to each
other.
e) How does the presence of the carbon-carbon double bond influence the effectiveness of the
intermolecular attractions?
f) What term describes the presence of a double bond in the hydrocarbon portion of this
molecule?
7. Construct eight water molecules and place them around the organic molecules oriented according to the
type of intermolecular bonds they would form.
g) What is the name of the intermolecular bonds that hold water molecules to these organic
molecules?
8. Remove the carbon-carbon double bond and return the molecule to its original condition.
9. Using the two 6-carbon molecules, add, remove, and rearrange atoms on both molecules to construct
two straight-chain glucose molecules.
h) What two functional groups do these molecules contain?
10. Attach a small piece of tape to the carbon atoms that are double bonded to an oxygen atom at one end of
each molecule. These are designated carbon-1 atoms.
11. Carefully change each straight-chained glucose molecule into a alpha-glucose ring. You may need to
reposition the hydroxyl groups to ensure that they are arranged above and below the plane of the ring.
12. Orient the two alpha-glucose rings so that the hydroxyl group on carbon-1 of one ring faces the hydroxyl
group of carbon-4 on the other.
13. Construct an alpha 1-4 glycosidic linkage by simulating a condensation reaction between the two
molecules.
i) What is the name of the resulting molecule?
j) What other compound forms as a result of the condensation reaction?
14. Disassemble all molecules and return balls and springs to their respective compartments.