Download structure of organic molecules

STRUCTURE OF ORGANIC MOLECULES
For many years scientists believed that only organisms were able to synthesize the
complex molecules needed for life. Since these molecules were only found in living
organisms or the products of organisms, they were called organic macromolecules.
Studies conducted by biologists and chemists have led to a greater understanding of these
complex molecules and how they are produced.
Carbohydrates, proteins and lipids are the macromolecules that are of particular interest
to scientists. They provide structure, biochemical control and energy for most organisms.
In this activity you will examine the structure of these organic macromolecules.
OBJECTIVES:
 Identify the three elements founds in all carbohydrates and lipids, and the four
elements found in all proteins
 Describe the molecular structure of carbohydrates, lipids and proteins
 Visualize the structure of carbohydrates, lipids and protein by constructing models
PART I
CARBOHYDRATES
Carbohydrates are macromolecules made up of monomers of simple sugars called
monosaccharides.
A.
Examine the structure of the two monosaccharides below:
GLUCOSE
FRUCTOSE
1.
Name the three elements found in each monosaccharide.
2.
Count the number of atoms of each element found in glucose and fructose. Use
this information to write the molecular formula for each monosaccharide below.
Glucose:
C__H__O__
Fructose:
C__H__O__
B.
CARBOHYDRTAE MODEL
You will create a simple carbohydrate by joining two monomers of monosaccharides
together.
1. Cut two glucose models from the organic molecules model paper. Be sure to cut
along the solid lines! Try to join the monosaccharides. Do they join together easily
like a puzzle? Explain.
2. Cut along the dotted lines to remove an H from one model and an OH from the other.
Try to join the monosaccharides. Do they join together easily? Explain.
3. Can you create a new molecule by joining the H and OH pieces together? Name the
molecule that you formed.
4. What is this type of chemical reaction called?
PART II
LIPIDS
Lipids are macromolecules made up of monomers of glycerol and fatty acids. There are
many different fatty acids. Below is the structure of butyric acid, one example of a fatty
acid. Some common lipids include oils, fats and waxes.
A.
Examine the structure of the glycerol and fatty acids molecules below:
GLYCEROL
BUTYRIC ACID
1.
Name the three elements found in the glycerol and fatty acid molecules above.
2.
Count the number of atoms of each element found in glucose and fructose. Use
this information to write the molecular formula for each molecule below.
Glycerol:
C__H__O__
Butyric Acid: C__H__O__
B.
LIPID MODEL
You will create a simple lipid molecule called a triglyceride by joining the glycerol and
fatty acids monomers together.
1. Cut glycerol, butyric acid, stearic acid and palmitic acids models from the organic
molecules model paper. Be sure to cut along the solid lines! Try to join the
glycerol and fatty acid molecules together like a puzzle. Do they join together easily?
Explain.
2. What step is necessary before joining the glycerol and fatty acid molecules? (Think
of what needed to be done in order to join the monosaccharides.)
3. Complete this step to create the lipid.
4. What molecule is formed by joining the H and OH pieces together? How many
molecules are formed?
5. What is this type of reaction called?
PART II
PROTEINS
Proteins are macromolecules made up of monomers called amino acids. There are
twenty amino acids found in living organisms. Different combinations of these twenty
amino acids make up every protein!
A.
Examine the structure of the two amino acids below:
GLYCINE
ALANINE
1.
Name the four elements found in each amino acid.
2.
What element is found in proteins but not in carbohydrates or lipids?
3.
Count the number of atoms of each element found in glycine and alanine. Use
this information to write the molecular formula for each amino acid below.
Glycine:
4.
C__H__O__N__
C__H__O__N__
The structure of every amino acid is very similar. Every amino acid consists of a
central carbon atom bonded to a single hydrogen atom and three characteristic
“groups.” Reexamine the glycine and alanine molecules shown below.
a. An amino group (NH2) is found in every amino acid. Put a
square around the amino group (NH2) in glycine and alanine.
b. A carboxylic acid group (COOH) is found in every amino
acid. Put a circle around the carboxylic acid group (COOH)
in glycine and alanine.
c. The third group consists of a variety of different atoms. This is
the group that makes one amino acid different from another.
This group is called the “R” group. In glycine molecule the
“R” group is a single H. In the alanine molecule the “R”
group is CH3. Place a triangle around the “R” groups of
glycine and alanine.
GLYCINE
B.
Alanine:
ALANINE
PROTEIN MODEL
You will create a simple protein molecule by joining the two amino acids together.
1. Cut glycine and alanine models from the organic molecules model paper. Be sure to
cut along the solid lines! Try to join the glycine and alanine molecules together like
a puzzle. Do they join together easily? Explain.
2. What step is necessary before joining the glycerol and fatty acid molecules?
3. Complete this step to create the protein.
4. What molecule is formed by joining the H and OH pieces together?
5. What is this type of reaction called?
ORGANIC MOLECULES MODEL PAPER
CARBOHYDRATE MODEL
LIPID MODEL
PROTEIN MODEL