Download Making Macromolecule Activity - Mercer Island School District

Name___________________________________________________________Date__________________Period_______
Making Macromolecules Activity
Purpose:
In this activity, students will mimic the reactions which create organic macromolecules. In the process
they will learn about the structure of biomolecules and the chemical processes by which they are metabolized.
Background: You will use a molecular modeling kit to construct models of carbohydrate, protein and lipid molecules.
By pairing up with other groups, you will be able to simulate the dehydration synthesis reactions which build organic
macromolecules, as well as the hydrolysis reactions which break them down.
Procedure:
1.
2.
3.
4.
Remember the following rules when building models with the molecular modeling kits:
Every hole must be attached to a bond (except nitrogen).
Every bond must connect two atoms.
Use short sticks for single bonds, long flexible sticks for double/triple bonds.
Each element is represented by a ball of a specific color:
a. Black (4 holes): carbon
b. Red (2 holes): oxygen
c. White (1 hole): hydrogen
d. Blue (3 holes): nitrogen
e. Yellow (6 holes): phosphorus
Pre-lab: Answer the pre-lab question on your question guide before starting.
A. Carbohydrates:
1. In your group, make a glucose molecule. Glucose is a monosaccharide. Make the ring structure first
using 5 carbon atoms and 1 oxygen. Then add the other atoms (1 more carbon, 12 hydrogens, 5 more
Oxygens).
2. When you are done. Make sure there are no empty spots for making bonds. All bonds should be the
shorter bond and not the longer flexible bond used for double bonds. Count your atoms and make sure
you have 6 Carbons, 12 Hydrogens, and 6 Oxygens.
C H2OH OH
O
CH
CH
OH
CH
CH
C
HO H OH
3. In partnership with another group, form a maltose molecule by removing water in a dehydration
synthesis reaction as shown on the next page. Maltose is a disaccharide.
Making a Disaccharide, maltose:
C H2OH OH
O
CH
CH
OH
CH
CH
C
HO H OH
+
C H2OH OH
O
CH
CH
OH
CH
CH
C
HO H OH
C H2OH OH
O
C H2OH
CH
CH
O H
C
CH
O CH OH CH

OH
C
CH
CH
H OH
C
HO H OH
+ H2O
maltose
Teacher’s Initials _________________
4. If you link your maltose with that from another group in another dehydration synthesis reaction, you can
form a small polysaccharide (starch) which will contain 4 monosaccharide subunits (glucoses).
5. Now reverse each step by adding the water molecule you removed in order to break apart the units in
the chain. This simulates hydrolysis, a decomposition reaction such as might happen during digestion.
B. Proteins:
1. Form the amino acid glycine:
O
H
C COH
H
H2 N
glycine
2. Use your textbook, chapter 2.3, to identify the amino end, carboxyl group, and the variant group (R) of your
amino acid.
Teacher’s Initials _________________
3. With another glycine molecule, form a small polypeptide by removing a water molecule in a dehydration
synthesis reaction as shown:
O
H2 N
H
C COH
H
O
O
+
H2N
H
C COH 
H
H2 N
O
H H
H
C C N C COH
H
H
+ H2O
NOTE: the new Carbon to Nitrogen bond formed between the two amino acids is called a peptide bond,
thus the name polypeptide for a short protein
Teacher’s Initials _________________
C. Lipids
1. Form glycerol and three fatty acids as shown:
O
H2COH
H H H
HOC C C C H
H H H
HCOH
H2COH
x3
glycerol
fatty acid
Teacher’s Initials _________________
2. Now join these molecules together with dehydration synthesis reactions as shown:
Common lipid
(Triglyceride)
H2COH
HCOH
H2COH
O
+
H H H
HOC C C C H
H H H
x3

O
H2CO C CH2 CH2 CH3
O
HCO C CH2 CH2 CH3
O
H2CO C CH2 CH2 CH3
+ H2O x 3
Teacher’s Initials _________________
Name: ________________________________________
Period ______
Making Macromolecules Question Sheet
PreLab Questions:
1. The gray sticks in the molecular modeling kits represent a _______________ which is a pair of
_________________________________________.
2.
A white ball represents a hydrogen atom. It has one hole. What does this represent? Refer to the periodic
table.
3. Why does the ball representing carbon, which is black, have four holes? Refer to the periodic table.
4.
Molecular models must fill all the holes in the atoms. (Fill the valence level of each of the atoms in order to
make a stable molecule.) To make an O2 molecule, (2 red pieces) you must use two sticks (the longer ones are
needed for this.) Explain what this tells us about the bond in O2.
Lab Questions:
1. What is the formula for glucose?
2. What type of carbohydrate does glucose represent?
3. Describe the structure of a glucose molecule (it can also have a linear structure but describe the structure that you
built which is the more common form).
4. Why is the reaction that joins together two monosaccharides into a disaccharide (or also two amino acids into a
dipeptide or glycerol and 3 fatty acids into a triglyceride fat) called a dehydration reaction?
5. What is the name for the type reaction that occurs when food is digested and is broken apart into the smaller units
(such as a disaccharide is broken into two monosaccharides)? Explain the meaning of this name (give the meaning of
the prefix and suffix).
6. Draw and label the parts of an amino acid and include: all of the atoms and bonds, the variant group (R), amino end,
carboxyl group. Use your textbook to help you, Chapter 2.3.
7. What atom is necessary to build protein that is not found in Carbohydrates and Lipids?
8. What type of bond did you create when you connected two amino acids (glycine and glycine) together?
9. What molecules (and how many of each) did you need to put together to form your common lipid (also known as a
triglyceride)?
10. Look at the structure of your lipid. Why do lipids store more energy per gram than carbohydrates (Lipids store 9 kcal
per gram compared to 4 kcal per gram for proteins and carbohydrates)?
Hint: Some bonds can store more energy than others. For instance, C-C bonds store more energy than C-O or C-H.