Download Oakland Schools Biology Resource Unit

Oakland Schools Biology Resource Unit 1
Chemistry and Biochemistry
Colleen Cain
Avondale High School
Avondale School District
Unit Table of Contents
Standards, Statements and Expectations
Instructional Background Information
Terms and concepts
Knowledge and Skills
Instructional Resources
Activity #1: Who Took Jerrel’s iPod?
Activity #2: Analyzing Food Labels
Activity #3: Pineapple Enzymes and Protein Lab
Activity #4: Dehydration Synthesis and Hydrolysis Virtual Simulation
Standards, Statements and Expectations
Standard B2: Organization and Development of Living Systems
Students describe the general structure and function of cells. They can explain that all
living systems are composed of cells and that organisms may be unicellular or
multicellular. They understand that cells are composed of biological macromolecules and
that the complex processes of the cell allow it to maintain a stable internal environment
necessary to maintain life. They make predictions based on these understandings.
B2.2 Organic Molecules
There are four major categories of organic molecules that make up living systems:
carbohydrates, fats, proteins, and nucleic acids.
B2.2x Proteins
Protein molecules are long, usually folded chains composed mostly of amino acids and
are made of C, H, O, and N. Protein molecules assemble fats and carbohydrates; they
function as enzymes, structural components, and hormones. The function of each protein
molecule depends on its specific sequence of amino acids and the shape of the molecule.
Content Expectations: (priority expectations are in BOLD)
B2.2A: Explain how carbon can join to other carbon atoms in chains and rings to form
large and complex molecules.
B2.2B: Recognize the six most common elements in organic molecules
(C, H, N, O, P, S).
B2.2C: Describe the composition of the four major categories of organic molecules
(carbohydrates, lipids, proteins, and nucleic acids).
B2.2D: Explain the general structure and primary functions of the major complex
organic molecules that compose living organisms.
B2.2E: Describe how dehydration and hydrolysis relate to organic molecules.
B2.2f: Explain the role of enzymes and other proteins in biochemical functions (e.g., the
protein hemoglobin carries oxygen in some organisms, digestive enzymes, and hormones).
B2.4 Cell Specialization
In multicellular organisms, specialized cells perform specialized functions. Organs and
organ systems are composed of cells and function to serve the needs of cells for food, air,
and waste removal. The way in which cells function is similar in all living organisms.
B2.4f: Recognize and describe that both living and nonliving things are composed of
compounds, which are themselves made up of elements joined by energy-containing
bonds, such as those in ATP.
B2.5 Living Organism Composition
All living or once-living organisms are composed of carbohydrates, lipids, proteins, and
nucleic acids. Carbohydrates and lipids contain many carbon-hydrogen bonds that also
store energy
B2.5x Energy Transfer
All living or once living organisms are composed of carbohydrates, lipids, proteins, and
nucleic acids. Carbohydrates and lipids contain many carbon-hydrogen bonds that also
store energy. However, that energy must be transferred to ATP (adenosine triphosphate)
to be usable by the cell.
B2.5A: Recognize and explain that macromolecules such as lipids contain high energy
bonds.
Return to Unit 1 Table of Contents
Instructional Background Information:
What is an organic compound?
All organic compounds contain carbon. The six most common elements in organic
compounds are C, H, N, O, P and S.
Life’s molecular diversity is based on the properties of carbon
Macromolecules have thousands of covalently connected atoms.
The atoms are connected by high energy bonds.
What happens when you make a bond? You store energy
What happens when you break a bond? You release energy
Monomers are the building blocks of polymers.
Dehydration synthesis (picture above) forms polymers by removing a water molecule.
Hydrolysis is the reverse of dehydration synthesis. Hydrolysis (picture below) uses water
to break bonds and form smaller molecules.
There are four major classes of macromolecules:
Carbohydrates, lipids, proteins, and nucleic acids.
Carbohydrates
Monosaccharides are monomers.
Disaccharides and polysaccharides are polymers.
Cells link single sugars to form disaccharides
Disaccharides are double sugars. Double sugars are made by
the process of dehydration synthesis.
Examples include maltose and sucrose:
a. glucose + glucose = maltose + water
monomer + monomer = polymer + water
b. glucose + fructose = sucrose + water
monomer + monomer = polymer + water
Polysaccharides are long chains of sugar monomers.
Polysaccharides are polymers of hundreds or thousands of monosaccharides linked
together by dehydration synthesis.
a. Plants store polysaccharides as starch in their roots.
b. Animals store polysaccharides as glycogen in their liver and muscle cells.
c. Plants use a polysaccharide called cellulose to build plant cell walls.
Lipids
Lipids include fats, which are mostly energy-storage molecules.
Lipids consist mainly of carbon and hydrogen linked by non-polar covalent bonds.
Lipids are not attracted to polar water molecules which make lipids hydrophobic.
“Fats” a.k.a. triglycerides are 3 fatty acids attached to the 3 carbons of a glycerol.
Glycerol = 3-carbon chain
Fatty acids = long chains of about 15 carbons
Return to Unit 1 Table of Contents
Lipids are made by the process of dehydration synthesis
Different kinds of fats:
•
Single bonds – saturated fats (usually solids
from animals such as butter)
•
Double or triple bonds – unsaturated fats
(usually liquids from plants such as corn and vegetable oils)
Atherosclerosis is a condition caused by too much saturated fat
in your diet causing lipid deposits (plaque) to accumulate in
your blood vessels, reducing blood flow.
Trans fats are unsaturated fats converted to saturated by adding hydrogens.
Example: usually a softened solid such as margarine.
Trans fats used to be called hydrogenated fats.
Phospholipids, waxes, and steroids are lipids with a variety of functions
Phospholipids - structurally similar to fats but contain phosphorus + 2 fatty acids
(not 3) are used mainly in membranes of the cell.
Waxes – one fatty acid linked to an alcohol (coating for fruits / insects have waxy
coats to prevent dehydration).
Steroids – carbons form rings such as in the case of cholesterol (also found in cell
membranes).
Proteins
Proteins are essential to the structures and activities of life.
Proteins are biological polymers constructed from amino acid monomers.
There are seven major classes of proteins:
1. Structural proteins - include hair, silk of spiders, fibers of
ligaments/tendons, etc.
2. Contractile proteins – the type involved in muscle movement
3. Storage proteins – ovalbumin (egg whites) for developing embryos
4. Defensive proteins – antibodies to fight infection
5. Transport proteins – hemoglobin that transports oxygen in blood stream
6. Signal proteins – hormones that serve as messengers from one cell to
another
7. Enzyme proteins - serve as chemical catalysts in regulating almost all
chemical activity (reactions) in the body
More information about enzymes
• Enzymes are large proteins that act as catalysts.
What is a catalyst?
Catalysts either jump start or speed up the rate of a chemical reaction.
• Catalysts are recycled, they are not used up in the reaction.
• Catalysts lower the amount of energy needed to turn reactants into products.
• Remember:
Return to Unit 1 Table of Contents
Reactants
Products
How does an enzyme work?
A specific enzyme catalyzes each cellular chemical reaction like each lock fits
only one key.
• Each enzyme has a part called the active site where the specific
substrate binds.
• The reactant is called the substrate.
o In the hydrolysis of sucrose, sucrose is the substrate (reactant).
o Sucrase is the name of the enzyme that catalyzes this reaction.
o The enzyme allows hydrolysis (adding a water molecule) to happen.
o The molecule of sucrose is then broken apart into a molecule of glucose
and a molecule of fructose.
o The enzyme sucrase goes on to find other sucrose molecules and repeat
the process.
• At the end of the reaction, the substrate changes into the product and the enzyme
is released.
What are proteins made of? Proteins are made from just 20 kinds
of amino acids.
All amino acids have the same basic structure.
The R group is what varies in the 20 different kinds of amino acids.
How are proteins made?
Proteins are made by the process of dehydration synthesis.
Nucleic Acids
Nucleic acids are information-rich polymers of
nucleotides
Nucleic acids are the blueprints for proteins
There are two types of nucleic acids:
DNA – deoxyribonucleic acid
RNA – ribonucleic acid
Genetic material consists of DNA, and within the DNA are gene. Genes are specific
stretches of the molecule that program the amino acid sequence of proteins. Monomers
that make up nucleic acids are called nucleotides.
RNA is a single polynucleotide strand and DNA is a double polynucleotide strand that
twists to form a double helix. Return to Unit 1 Table of Contents
Pictures in Instructional Background Information:
Campbell, Neil. (2000) Biology: Concepts and Connections. San Francisco, Addison
Wesley Longman, Inc.
Return to Unit 1 Table of Contents
Terms and Concepts
ATP
Carbohydrate
Catalyst
Chemical bond
Covalent bonds
DNA
Dehydration synthesis
Element
Enzyme
Hemoglobin
High energy bonds
Hormone
Hydrolysis
Lipid
Nucleic acid
Protein
Polymers
RNA
Substrate
Knowledge and Skills
Student should be able to:
Identify representations of large biological molecules as polymers of simple subunits.
Identify structural formula of amino acids.
Identify the structural relationships formulas of monomers of fats, proteins, carbohydrates (fatty
acids, amino acids, simple sugars).
Identify the between enzymes and substrates.
Identify the role of dehydration synthesis and hydrolysis in the building and breaking down of
macromolecules.
Return to Unit 1 Table of Contents
Instructional Resources:
This website has many hands on biology activities.
http://serendip.brynmawr.edu/sci_edu/waldron
This website has links to biology labs and lectures.
www.explorebiology.com
This website has great interactive simulations.
http://www.explorelearning.com/
Return to Unit 1 Table of Contents
Chemistry and Biochemistry
Activity #1: Who took Jerell’s iPod?
Questions to be investigated: What are the different types of organic compounds? How are
these types of compounds tested for?
Biology HSCE’s addressed:
B2.2 Organic Molecules There are four major categories of organic molecules that make up
living systems: carbohydrates, fats, proteins, and nucleic acids.
B2.2x Proteins Protein molecules are long, usually folded chains composed mostly of amino
acids and are made of C, H, O, and N. Protein molecules assemble fats and carbohydrates; they
function as enzymes, structural components, and hormones. The function of each protein
molecule depends on its specific sequence of amino acids and the shape of the molecule.
B2.2C: Describe the composition of the four major categories of organic molecules
(carbohydrates, lipids, proteins, and nucleic acids).
Materials:
-Containers for testing food such as test tubes, specimen jars, etc.
-Stirrers, such as plastic spoons
-Masking tape for labeling testing containers
-Biuret reagent for protein testing (approximately 4 ml per student lab group)
-Iodine-Potassium Iodide Solution for starch testing (approximately 1 ml per student lab group)
-Glucose test strips (5 per student lab group for the first day and 1 per student lab group for the
second day) – an alternative to the strips is Benedict’s solution
-Brown paper bag for lipid testing (1 per student lab group; half for each day)
-Gloves (1 or 2 per student for each day)
-Samples for testing
Day 1: (approximately 1.5 ml of each per student lab group)
Vegetable oil
Corn starch
Powdered egg whites (can be found in the baking needs aisle)
Glucose (may also be sold as Dextrose, can be found online, in the pharmacy often times
in tablet form, or sometimes, in a cake decorating supply store (e.g. Joann’s))
Day 2: (approximately 3 ml of each per class)
Pretzels
Butter
Jelly (You may want to make sure this tests positive for glucose; we have had success
with strawberry jelly and we believe that any jelly sweetened with high fructose
corn syrup will test positive for glucose.)
Fat-Free or low-fat vanilla or plain yogurt
Beans (canned beans that have been mashed into a paste; e.g. canned white beans)
*Save the labels with nutrition information from all the food packages. These will be useful for
discussing any discrepancies between predictions and observed results.
Return to Unit 1 Table of Contents
Return to Unit 1 Table of Contents
Safety Concerns: Students should at least wear gloves while performing tests for carbohydrate
and proteins; goggles are also recommended. You may also want to keep the Biuret reagent and
iodine solution at your desk and have students come to pick it up when they need it.
Real-World Connections: Students relate study of macromolecules to the nutrients in the food
they eat.
Teacher Notes: This activity reinforces student understanding of different types of organic
compounds and several aspects of scientific method. Before you begin this activity, your
students should be familiar with the basic chemical structures and general properties of
carbohydrates, proteins and lipids. Helpful teacher notes can be found online at
http://serendip.brynmawr.edu/exchange/waldron/organic
You will need to make evidence samples for Day 2. We suggest that you make four different
pairs of dry and liquid evidence samples so different student groups will get different results.
Worker
in break
room
Jose
Ashley
Bruce
Kiara
Lunch/Snack
Bean burrito with
cheese
Fat-free yogurt
Toast with butter and
jelly
Pretzels
Solid
Evidence
Glucose
Liquid
Evidence
Lipid
A
-
+
+
A
+ (oil)
B
+
-
+
B
- (water)
C
+
+
-
A
+ (oil)
D
-
+
-
B
- (water)
Starch Protein
Procedure/Description of Lesson: In the first class period, students learn how to use chemical
indicators to test for different types of organic compounds, and in the second class period each
student group will test one or two types of food or a sample of evidence to figure out who took
Jerell's iPod. You may want to assign each type of food or evidence to two student groups in
order to assess reliability of results.
Source: Dr. Jennifer Doherty, Dr. Ingrid Waldron and Dr. Lori Spindler, Department of
Biology,University of Pennsylvania, copyright 2009 1, serendip.com, Adapted from “Identity of
Organic Compounds” from Biology Laboratory Manual A from Prentice-Hall; Also inspired by “Crime Scene
Activity” by Kathy Paris, Bethel High School
Who took Jerell’s iPod? -- An organic compound mystery
Jerell is a 10th grade student at City High School who works at McDonald’s on the weekends.
While on break, Jerell was studying for his biology test and listening to his new iPod. There
were four other workers taking a break at the same time, each having something different for
lunch.
Jerell’s girlfriend stopped by near the end of his break, and he rushed out to see her and forgot
his iPod and biology book in the break room. When he realized he had forgotten it, he hurried
back and found only his biology book and some food crumbs. His iPod was gone!
Return to Unit 1 Table of Contents
Return to Unit 1 Table of Contents
First, Jerell freaked out, but he calmed down when he realized he could use his knowledge of
organic compounds to figure out which of his coworkers left the crumbs on his textbook and who
took his iPod.
What are organic compounds?
Almost all of the food we eat comes from plants and animals. Plants and animals contain mainly
water and organic compounds, which are molecules made by living organisms such as plants or
animals. The table below lists the most common types of organic compounds found in living
organisms. For each type of organic compound, give one or two examples and describe one
characteristic, e.g. whether it is greasy, whether it contains genetic material, whether there is lots
of this type of organic compound in meat or lots in pretzels and potatoes.
DATA TABLE 1:
Type of Organic
Examples of Food That Has
Characteristic of Food That
Compound
Lots of This Type of Organic
Has Lots of This Type of
Compound
Organic Compound
Carbohydrates
Lipids
Nucleic acids
Proteins
Today you will be testing the substances listed in the following table. Predict whether each
substance is an organic compound and if so, what type.
DATA TABLE 2:
Substance
Do you think this substance is a carbohydrate,
lipid, protein, or none of these?
Vegetable oil
Glucose
Starch from corn or potatoes
Powdered egg whites
Water
What are indicators?
An indicator is a substance that changes color in the presence of a particular type of molecule.
Today you will learn how to use several indicators to test for the presence of carbohydrates and
proteins. You will also use a different type of test for lipids. Tomorrow, you will use these tests
to analyze several types of food and the evidence left at the scene of the crime to find out who
left the crumbs on Jerell’s textbook.
Testing for lipids
1. If a food that contains lipids is put on brown paper, it will leave a spot that lets light through.
To test for lipids, divide a piece of a brown paper bag into 5 sections. Label the sections
"vegetable oil", "glucose", "starch", "egg whites", and “water”.
2. In each section, rub a small amount of the substance onto the brown paper.
Return to Unit 1 Table of Contents
Return to Unit 1 Table of Contents
With a paper towel, rub off any excess that may stick to the paper. Set the paper aside until the
spots appear dry—about 10 to 15 minutes.
3. Which section do you expect to test positive for lipids?
4. Which sections do you expect to test negative for lipids?
5. Continue on with the rest of the tests. After all the sections of the brown paper are dry, hold
it up to a bright light or window. You will notice that at least one sample has left a spot that
lets light through on the brown paper. The spot indicates the presence of lipids.
6. Complete the last column of data table 3. Put a plus for any samples which tested positive
for lipids and a minus for the samples which tested negative.
DATA TABLE 3:
Carbohydrate Tests
Sample
Test strip
color
Glucose
present
Iodine
test color
Protein Test
Starch
present
Biuret
test color
Protein
present
Lipid
Test
Lipid
present
Vegetable oil
Glucose
Starch from corn
or potatoes
Powdered
egg whites
Water
Testing for Carbohydrates
1. You must wear gloves to protect yourself.
2. You will use indicators to test for two common types of carbohydrates: glucose (a specific
type of sugar) and starch. Obtain 5 containers and use masking tape to make labels for each
container. Label the containers "vegetable oil", "glucose", "starch", "egg whites", and
“water”.
3. For each container, add a small amount of the substance indicated on the masking-tape label.
Now add about 2 ml of water to each container. Stir the contents of each container to mix the
sample and water.
Return to Unit 1 Table of Contents
Return to Unit 1 Table of Contents
To test for glucose you will use a test strip with an indicator pad that changes color in the
presence of glucose. Prepare a piece of paper with the name of each substance and a place to put
the glucose test strip used to test that substance. Dip one test strip into each sample for 1-2
seconds. Remove the strip, put it in the appropriate spot on your labeled paper, and wait 3
minutes.
4. Which substance do you expect to test positive for glucose?
5. Which substances do you expect to test negative for glucose?
6. After 3 minutes, record the color for each glucose test strip in the data table 3. Put a plus
next to those samples testing positive for glucose and a minus for those testing negative.
7. To test for starch you will use iodine as an indicator. In the presence of starch, iodine will
change color from yellow-brown to blue-black. Add 5 drops of iodine solution to each
container. Stir the contents of each container.
CAUTION: Be careful when handling iodine; it can stain hands and clothing.
8. In data table 3, record the color of the iodine solutions. Put a plus next to those samples
testing positive for starch and a minus for those testing negative.
Testing for Proteins
1. Label five clean containers "vegetable oil", "glucose", "starch", "egg whites", and “water”.
Add a small amount of the substance indicated on the label to each container. Add about 2
ml of water to each container. Stir the contents of each container to mix the food and water.
2. To test for protein you will use Biuret reagent as an indicator. Biuret reagent turns from blue
to purple in the presence of protein. Add 20 drops of biuret reagent to each container. Stir
the contents of each container.
CAUTION: Biuret reagent contains sodium hydroxide, a strong base. Be very careful not
to splash or spill any. If you splash any reagent on yourself, wash it off immediately with
water. Call your teacher for assistance.
3. Record the color of each Biuret solution in data table 3. Put a plus next to those samples
testing positive for protein and a minus for those testing negative.
4. Rinse all ten containers thoroughly.
Questions
1. Compare your predictions from data table 2 with your test results in data table 3. Were there
any differences between your test results and your predictions for what type of organic
compound each test substance is?
Return to Unit 1 Table of Contents
Return to Unit 1 Table of Contents
If you found any differences between your predictions and your results, what do you think is the
reason for these differences? You may want to check with your teacher, your textbook, or the
nutrition information in the label on each food package to help you interpret your results.
Did your test for glucose indicate there was glucose in the starch sample?
Does that mean that there is no glucose in starch? (Hint: Check your textbook or other
reliable source if you do not already know the chemical structure of starch.)
This result shows that the glucose indicator is quite specific. It reacts with glucose dissolved in
water, but it does not react with glucose molecules that are combined into a large organic
compound like starch.
2. Suppose that for the container containing water you found a positive test for one of the organic
compounds. How would you interpret this result?
Testing Different Types of Food and Testing the Evidence
Today you will perform all four organic compound tests on one or two of the types of food listed
below or on the evidence that Jerell found at the crime scene (your teacher will assign you
samples to test). Begin by predicting which types of compounds you expect to find in each type
of food you will be testing.
DATA TABLE 4
Food
Do you expect this food to contain
Glucose?
Starch?
Protein?
Lipid?
Pretzel
Butter
Jelly
Fat-free yogurt
Beans
Record your positive and negative test results using plus and minus signs in the data table below.
The evidence that Jerell found has been separated into a liquid and a solid in two separate bottles.
After you perform the tests, your teacher will collect your data to share with the rest of the class.
Complete the table below using data from your classmates.
DATA TABLE 5
Lipid
Carbohydrate Tests
Protein Test
Test
Food
Test strip
Glucose
Iodine
Starch
Biuret
Protein
Lipid
color
present
test color
present
test color present
present
Pretzel
(crumble into
the container)
Butter
Jelly
Fat-free yogurt
Beans (mash
into
a paste)
Return to Unit 1 Table of Contents
Dry part of
Jerell’s
evidence
Liquid part of
Jerell’s
evidence
Who took Jerell’s iPod?
The workers in the break room are listed below with the type of lunch they were eating while
Jerell was studying. As preparation for interpreting the evidence, complete the chart below to
indicate what kinds of organic compounds are found in each type of food and what kinds of
organic compounds were found in the combined liquid + dry evidence.
Worker
in break
Lunch/Snack
Glucose Starch Protein Lipid
room
Jose
Bean burrito with cheese
Ashley
Fat-Free Yogurt
Bruce
Toast with butter and jelly
Kiara
Pretzel
Thief
Combined liquid + dry evidence
Complete the following table to summarize the evidence and your interpretation of the evidence.
Did he/she
Worker
take
How do you know?
in break
Jerell’s
Describe the evidence that supports your conclusion.
room
ipod?
Jose
Ashley
Bruce
Kiara
Return to Unit 1 Table of Contents
Analysis Questions:
1. Who took Jerell’s iPod? Do you have any doubts about your conclusion? Explain.
2. Our bodies are made up of the same types of organic compounds as all other living organisms.
Complete the following sentences by filling in each blank to indicate the function of each type of
molecule in different parts of our body.
Our muscles contain lots of protein. This protein enables the muscles to _____________.
Glucose is carried by our blood to all the cells in our body. Our cells use the glucose for
_______________.
Lipids are found in fat cells in our bodies. The fat cells store fat molecules to be used for
______________ if a person cannot get enough food.
Our bodies do not make starch, but we often eat plant foods which contain starch which
we digest to _____________, the building block that is used to make starch.
DNA is a nucleic acid that is found in every cell. DNA carries the ____________
information.
3. To show your understanding of organic compounds, identify the type of organic compound
shown in each diagram and complete the first three columns of the table.
4. Many large organic compounds are made of multiple repeats of smaller building block
compounds. Starch, proteins, and nucleic acids are examples of this type of organic compound.
Circle a building block in the starch, protein, and nucleic acid figures, and write the name of the
building block in the fourth column.
Which test is used to
Type of
Name of
Diagram of Structure of Organic
detect this compound
Functions
Organic
building
Compound
or type of
Compound
block
compound?
Return to Unit 1 Table of Contents
Not tested for
Return to Unit 1 Table of Contents
Return to Unit 1 Table of Contents
Chemistry and Biochemistry
Activity #2: Analyzing Food Labels
Questions to be investigated: What types of organic compounds are in the food we eat? Is
high fructose corn syrup worse for you than sugar?
Biology HSCE’s addressed: B2.2C: Describe the composition of the four major categories of
organic molecules (carbohydrates, lipids, proteins, and nucleic acids).
Materials: Food Labels
Safety Concerns: N/A
Real-World Connections: Students relate study of macromolecules to the nutrients in the food
they eat by studying sugar and HFCS.
Teacher Notes:. Students collect food labels from home showing products both with and
without hfcs. You can introduce this activity by showing one of the commercials discussing high
fructose corn syrup. Student understanding can be assessed through by having students conduct
research on the opposing viewpoints of high fructose corn syrup and conduct a debate in class.
Procedure/Description of Lesson: Students will find food labels at home that have different
sweeteners. They will then research the different sweeteners and have a debate.
Instructions:
1. Looking in your pantry or cupboards at home, read the labels to find out which foods contain
high fructose corn syrup, glucose (also known as dextrose), or no high fructose corn syrup.
2. Staple or tape each label in the appropriate space below.
You must highlight or underline the label where the type and
amount of the sugar is identified.
High Fructose Corn Syrup (HFCS) label including the
ingredients:
Staple label here and highlight or underline high fructose corn
syrup (HFCS)!
Glucose (also known as dextrose) label including the ingredients:
Return to Unit 1 Table of Contents
Return to Unit 1 Table of Contents
Staple label here and highlight or underline glucose/dextrose!
A label with NO High Fructose Corn Syrup (HFCS):
Staple label here that has NO high fructose corn syrup (HFCS)!
Assessment Ideas:
Student understanding can be assessed through class discussion at the conclusion of the activity
as well as completion of the assignment and article extension. Also, you can follow up this
activity by having students conduct research on the pros/cons of high fructose corn syrup and
conduct a debate in class. The debate could be done as a ‘silent debate.’ This is a writing
strategy where each student must pick a side. The first student writes down a statement to
support their position, passes the paper to the second student who debates that statement with
their own argument. This continues for a set amount of time (~7 minutes). Opposing viewpoints
can be found at the following links:
McLaughlin, Lisa. “Is High-Fructose Corn Syrup Really Good for You?” Time.com.
September 17, 2008
Zeratsky, Katherine. “High-fructose corn syrup seems to be a common ingredient in many
foods. What are the concerns about high-fructose corn syrup?” Mayoclinic.com
Princeton University. "High-Fructose Corn Syrup Prompts Considerably More Weight Gain,
Researchers Find." ScienceDaily 22 March 2010. 25 June 2010 <http://www.sciencedaily.com
/releases/2010/03/100322121115.htm
Return to Unit 1 Table of Contents
Return to Unit 1 Table of Contents
Chemistry and Biochemistry
Activity #3: Pineapple Enzymes and Protein Lab
Questions to be investigated: How do enzymes and substrates work?
Biology HSCE’s addressed: B2.2f: Explain the role of enzymes and other proteins in
biochemical functions (e.g., the protein hemoglobin carries oxygen in some organisms, digestive
enzymes, and hormones).
Materials:
Fresh pineapple
Boiling & ice water
Canned pineapple
Test tubes & rack
Frozen pineapple
Spoons, stirring rods
Jell-O
Knife for chopping pineapple
Beakers
Safety Concerns: Goggles are recommended.
Real-World Connections: Students relate study of macromolecules to the nutrients in the food
they eat by studying sugar and HFCS.
Teacher Notes: Students will need to be familiar with the scientific method and have an
understanding of macromolecules. Gelatin is made from the protein collagen (from the joints of
animals). To make Jell-O, gelatin is dissolved in hot water, then allowed to cool. When the
dissolved gelatin cools, collagen makes a matrix, trapping the water. This is what results in the
jiggly texture of Jell-O. Bromelain(found in fresh pineapple) breaks down collagen, this enzyme
is denatured in canned pineapple. In this lab, pineapple contains the enzyme bromelain, jello is
the substrate and the processing of pineapple denatures the enzyme bromeain.
Procedure/Description of Lesson: Students will create a lab to study the affect of pineapple
on gelatin.
Source: adapted from a lab by Kim Foglia, explorebiology.com
Background information:
If you have ever made Jell-O by cooking the powder that comes in a box, you may have noticed
the warning on the instructions that tell you not to add fresh or frozen pineapple to the gelatin.
Have you ever wondered why? In this lab, you will be designing an experiment to test what is
really happening when you add pineapple to gelatin. You know enough organic chemistry now
to figure this out. First, you need a little background about gelatin… and it may be more than
you ever wanted to know. Do you know what Jell-O is really made out of? Are you ready? That
sweet colorful treat is actually made out of hides, bones, and inedible connecting tissue from
animals butchered for meat. No? Yup! All gelatin (including those made for photographic and
laboratory use, as well as for desserts) is made out of discarded animal parts — the tough parts:
bone and skin. And all these tough parts are made of proteins. In fact, the extracted gelatin is a
protein. So, why do you think gelatin gets thick and jelly-like when you cook it? (We’ll come
back to that later.) Gelatin can be extracted from any kind of animal, but cows are most common.
If your Mom or Dad have ever made a batch of chicken soup from scratch, you've probably seen
how it gets stiff and Jell-O like after it sits in the fridge… that's because boiling the chicken in
water extracts the gelatin from the carcass (bones & cartilage), just like a miniature version of
the commercial gelatin factories! Commercial gelatin making starts by grinding up bones. The
crushed bones are then soaked in a strong base (high pH) to soften them, and then passed through
Return to Unit 1 Table of Contents
progressively stronger acid (low pH) solutions, until the end result isn't recognizable as bones at
Return to Unit 1 Table of Contents
all! Then the whole mess is boiled for hours to extract the gelatin… and this part really makes a
stink! Finally, the gelatin layer is skimmed off the boiling pot, and dried into a powder. With
added sugar, flavorings, and artificial color, it's ready to become a jiggly dessert! And now that
you know what Jell-O's made from, why don't you put some on the table tonight? Your guests
will be delighted when you share your new knowledge with them in the middle of a luscious
spoonful of dessert! By the way, this whole process of extracting gelatin from bone was
originally developed in 1845 by an engineer, Peter Cooper — the man who Cooper Union (in
NYC) is named after. Sometime later (1895), Pearl B. Wait, a cough syrup manufacturer, bought
the patent from Peter Cooper and adapted Cooper's gelatin dessert into an entirely prepackaged
form, which his wife, May David Wait, named "Jell-O." The rest is history...
Made from bone… made from protein… so it must be tough stuff! So why can’t you put fresh
pineapple in it?
Let’s learn a bit about pineapple. The pineapple plant (Ananas comosus) is a monocot, or
grass-like plant, that belongs to the bromeliad family. It is thought to have originated in Brazil.
In the 1950s, pineapple became the United State’s second most important fruit and Hawaii led
the world in both quantity and quality of pineapples. However, times have changed and now, all
canned pineapple comes from overseas, largely from the Philippines. As with some other
tropical fruits, the pineapple fruit contains an enzyme that breaks down, or digests, protein. This
protease (protein-digesting) enzyme in pineapple is called bromelain, which is extracted and
sold in such products as Schilling's Meat Tenderizer. Papaya, another tropical fruit, also contains
an enzyme, called papain, that digests protein. It can be found in Accent Meat Tenderizer.
Procedure:
In this lab, you will be given an array of materials and you will be asked to design your own
experiment to test the effect of pineapple on gelatin. The goal is to understand what is actually
going on in the pineapple-gelatin mix at a chemical level as well as understanding what affects
the function of enzymes.
Design a controlled experiment that shows the effect of raw pineapple on gelatin.
Make sure your experiment description includes the following:
A hypothesis
A detailed experimental design which will include:
The effect of fresh pineapple on gelatin.
The effect of frozen pineapple on gelatin.
The effect of canned pineapple on gelatin.
The effect of freshly cooked pineapple on gelatin.
A data table
You will be able to perform your experiment once you receive approval of your
experimental design from your teacher.
Return to Unit 1 Table of Contents
Return to Unit 1 Table of Contents
Experimental Design Guide
Teacher Approval_________
Title:
Hypothesis:
Independent Variable:
Measurement of Independent Variable:
Number of Trials:
Dependent Variable:
Measurement of Dependent Variable:
Control:
Other Controlled Factors (At Least 5):
Questions:
1. Clearly describe the results of your experiment. In which test tubes did the gelatin jell,
which did not.
2. Clearly explain the results of your experiment. Why did some test tubes of gelatin jell,
why did others not. Be specific!
3. What is the enzyme in your experiment?
4. What is the substrate in your experiment?
5. What is (are) the product(s) in your experiment?
6. What type of organic molecule is gelatin?
7. What type of organic molecule is bromelain?
8. Write a “word equation” to describe the chemical reaction that occurs when pineapple is
mixed with the gelatin.
9. Is the reaction of bromelain and gelatin dehydration synthesis or hydrolysis? Explain.
10. Why were the results of the freshly cooked pineapple different than the results of the
fresh, raw pineapple? Be specific!
11. What is meat tenderizer and what does it do?
Assessment Ideas: On the accompanying sheet of paper, design an experiment to test at what
specific temperature the pineapple enzyme denatures.
Title:
Hypothesis:
Independent Variable:
Measurement of Independent Variable:
Number of Trials:
Dependent Variable:
Measurement of Dependent Variable:
Control:
Other Controlled Factors (At Least 5):
Return to Unit 1 Table of Contents
Return to Unit 1 Table of Contents
Chemistry and Biochemistry
Activity #4: Dehydration Synthesis and Hydrolysis Virtual Simulation
Questions to be investigated: How do the processes of dehydration synthesis and hydrolysis
work to build and break organic molecules?
Biology HSCE’s addressed: B2.2E: Describe how dehydration and hydrolysis relate to organic
molecules.
Materials: Computers with internet access
Safety Concerns: N/A
Real-World Connections: Students will use a virtual simulation to visualize dehydration
synthesis and hydrolysis.
Teacher Notes: This lesson would fit best after students have obtained a solid understanding of
macromolecule structure and dehydration synthesis and hydrolysis. The simulation is found on
the site ‘explorelearning.com.’ The name of the ‘gizmo’ is ‘dehydration synthesis.’ If your
school does not have access to this website, you can sign up for a free 30 day trial.
Procedure/Description of Lesson: Students build on prior knowledge and view simulation of
dehydration synthesis and hydrolysis.
Source: ExploreLearning Gizmos™
Dehydration Synthesis
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. If you exercise on a hot day, you need to worry about dehydration. In this context, what do you
think dehydration means?
2. Astronauts and backpackers often bring dehydrated food. What do you think dehydrated food is?
Gizmo Warm-up
What do rice, potatoes, and sugar have in common? They
are all foods rich in carbohydrates. Carbohydrates are an
important energy source for your body. The basic building
block of most carbohydrate compounds is the molecule
glucose. Using the Dehydration Synthesis Gizmo™, you
will learn about the structure of a glucose molecule and
how glucose molecules can be joined together to make
larger carbohydrate molecules.
To begin, select the CREATE GLUCOSE tab.
1.
Look at the chemical formula for glucose. How many
carbon (C), hydrogen (H), and oxygen (O) atoms are found in a molecule of glucose?
C:_______ H:_______ O:_______
2. Turn on Show chemical structure. Each black sphere represents a carbon, hydrogen, or oxygen
atom. The lines connecting the spheres represent chemical bonds.
How many black spheres are in the diagram? _______
Return to Unit 1 Table of Contents
Return to Unit 1 Table of Contents
A.
How does this relate to the number of carbon, hydrogen, and oxygen atoms in the
chemical formula for glucose? ___________________________________________
Activity A:
Get the Gizmo ready:
Be sure the CREATE GLUCOSE tab is still
Build a glucose
selected.
molecule
Introduction: Each element tends to form a certain number of chemical bonds. This value is the
valence of the element. For example, a carbon atom has a valence of four.
Goal: Construct a molecule of glucose.
1.
Identify: The structure of a water molecule (H2O) can be written as H-O-H, which
each dash representing a chemical bond. Count the number of bonds the oxygen and
hydrogen atoms form in a water molecule.
A. What is the valence of oxygen? _______
_______
2.
B. What is the valence of hydrogen?
Build a model: Use the carbon, oxygen, and hydrogen atoms from the Atoms box to
build a glucose molecule on the empty hexagon in the building region. Use the chemical
structure in the lower right as a guide, and pay attention to the valence of each atom as
you build.
Once you think you have correctly constructed the glucose molecule, click Check. If
necessary, continue to modify your molecule until it is correct.
3. Make a diagram: Congratulations, you have completed a molecule of glucose! Click
the COPY SCREEN button to take a snapshot of your completed molecule. Paste the
image into a blank document and label the image “Glucose.”
4. Explain: How did the valence of each element help you determine the structure of the
glucose molecule?
5.
Make connections: Carbon forms the backbone of every major type of biological
molecule, including carbohydrates, fats, proteins, and nucleic acids. How does
carbon’s high valence relate to its ability to form these large and complex
biomolecules?
Activity B:
Dehydration
synthesis
Get the Gizmo ready:
• Select the DEHYDRATION tab.
Return to Unit 1 Table of Contents
Return to Unit 1 Table of Contents
Question: What occurs when two glucose molecules bond?
1. Infer: Glucose is an example of a monosaccharide, the simplest type of carbohydrate.
A disaccharide is made from bonding two monosaccharides together.
A. What do you think the prefixes mono- and di- mean? Mono-: __________ Di-:
__________
2. Predict: Turn on Show description. Drag both glucose molecules into the building
region. Observe the highlighted region. What do you think will happen to the atoms in
this region when the glucose molecules bond?
3. Run Gizmo: Click Continue and watch the animation.
A.What happened?
B.What was removed from the glucose molecules when they bonded to form maltose?
4. Infer: Based on what you have seen, create a balanced equation for the dehydration
synthesis reaction. (Recall that the formula for glucose is C6H12O6.) You will have to
determine the formula of maltose yourself.
5.Turn on Show current formula/equation to check your answer.
6.Summarize: Use what you have observed to explain what occurs during a dehydration
synthesis reaction.
7.Apply: A trisaccharide is a carbohydrate made of three monosaccharides. What do you
think would be the chemical formula of a trisaccharide made of three bonded glucose
molecules?
Get the Gizmo ready:
Activity C:
• Select the Hydrolysis tab.
• Turn on Show description and Show current
Hydrolysis
formula/equation.
Introduction: Carbohydrates made up of three or more bonded monosaccharides are
known as polysaccharides. In a reaction known as hydrolysis, your body breaks down
polysaccharides into individual monosaccharides that can be used by your cells for
energy.
1. Predict: Examine the polysaccharide in the building region and its chemical formula.
A. How many monosaccharides can form if this polysaccharide breaks up?
B. Recall the formula of glucose is C6H12O6. How many carbon, oxygen, and hydrogen
atoms will you need for three glucose molecules?
Return to Unit 1 Table of Contents
C. What must be added to the polysaccharide in the Gizmo to get three glucose
molecules?
2.
Observe: Turn off Show current formula/equation. Drag a water molecule into the
building region. Click Continue. What happened?
3. Infer: Create a balanced equation for the hydrolysis reaction that just occurred.
Turn on Show current formula/equation to check your answer.
4.
Observe: Turn off Show current formula/equation. Drag the second water
molecule into the building region. Click Continue. What happened?
5.
Summarize: Now create a balanced equation that shows the entire hydrolysis
reaction. (In other words, the equation should show how the polysaccharide broke up
into three separate glucose molecules.)
Turn on Show current formula/equation to check your answer.
6. Compare: How do hydrolysis reactions compare to dehydration synthesis reactions?
7. Apply: Amylose is a polysaccharide made from the synthesis of four glucose
molecules.
A. How many water molecules are produced when amylose forms?
B. What do you think is the chemical formula for amylose?
C. How many water molecules would be needed to break amylose down into four
glucose molecules?
8. Extend your thinking: Hydrolysis of the carbohydrates you eat begins in your mouth
as you chew. How do you think this process might be affected if a person’s salivary
glands were unable to produce saliva, which is mostly composed of water?
Assessment Ideas: Gum Drop Chemistry
Have students use their diagrams of a glucose molecule from activity A of the Student
Exploration sheet to build a model of glucose using toothpicks and gum drops (or mini
marshmallows). Make sure all students use the same color of gum drops to represent
each type of atom. Write the color key on the board as a reminder for students. After each
student builds their gum drop model, have students form pairs. The students should
model how two glucose molecules can bond to form a molecule of maltose and a
molecule of water. Next, have students model hydrolysis by reversing the reaction. This
can also be done with molecular kits.
Return to Unit 1 Table of Contents