TEKS 10 A & B
Digestion
Nutrition/Macromolecules
Enzymes
TAKS Objective 2 – The student will demonstrate an understanding of
living systems and the environment.
TEKS Science Concepts 3 B
The student uses critical thinking and scientific problem solving to make
informed decisions. The student is expected to:
(B) evaluate promotional claims that relate to biological issues such as
product labeling and advertisements;
9A&C
The student knows metabolic processes and energy transfers that occur in
living organisms. The student is expected to:
(A)
compare structures and functions of different types of
biomolecules such as carbohydrates, lipids, proteins, and
nucleic acids;
(B)
compare the energy flow in photosynthesis to the energy flow in
cellular respiration;
(C)
investigate and identify the effects of enzymes on food
molecules; and
(D)
analyze the flow of matter and energy through different tropic
levels and between organisms and the physical environment.
TAKS Objective 2
page 1
Biology
10 A & B
The student knows that, at all level of nature, living systems are found
within other living systems, each with its own boundary and limits. The
student is expected to:
(A) interpret the functions of systems in organisms including
circulatory, digestive, nervous, endocrine, reproductive,
integumentary, skeletal, respiratory, muscular, excretory, and
immune;
(B) compare the interrelationships of organ systems to each other
and to the body as a whole;
11 C
The student knows that organisms maintain homeostasis. The student is
expected to:
(C) analyze the importance of nutrition, environmental conditions, and
physical exercise on health
TAKS Objective 2
page 2
Biology
For Teacher’s Eyes Only
Teacher Background: There are twelve major organ systems in the human body
(i.e., circulatory, skeletal, respiratory, excretory, integumentary, nervous,
digestive, endocrine, reproductive, immune, lymphatic, and muscular systems). In
this TEKS, we will introduce students to the common structures of each system
and their basic functions. A brief description of these systems follows:
Digestive System – Our digestive system functions to break down our food into
smaller, useful elements that can be absorbed and utilized by our body for energy.
Once absorbed, these fundamental elements can either be used in their immediate
form or transformed and integrated into building molecules that are more
complex.
The vital components of the digestive system include the mouth (saliva), pharynx,
peristaltic motion of the esophageal muscles to work food down to the acidic
digestive juices of the stomach. Once in the stomach the food particles are broken
down into small components and bile produced by the liver and stored in the gall
bladder, emulsify fat and the partially digested food particles. The food then
passes through to the small intestine where other accessory organs release
enzymes to break down the food particles into their most elemental forms to be
absorbed through structures called microvilli. Finally, the waste matter passes
through the large intestine (colon) where fluids and minerals are reabsorbed. The
remaining indigestible matter is then stored in the rectum and excreted from the
anus.
Macromolecules –
Student Prior Knowledge
Students should be familiar with the components associated with body systems
TEKS 6.10 (C) identify how structure complements function at different levels of
organization including organs, organ systems, organisms, and populations and the
functions of these systems.
TAKS Objective 2
page 3
Biology
More than Just a Gut Feeling
5 E’s
ENGAGE
Watch digestive system clip with gold medalist Bonnie Blair from PBS video
Universe Within. Have student complete the film guide while watching this
section of the video. Use the guide to stimulate discussion after this section of the
movie is finished.
EXPLORE
Digestion Simulation
By participating in this simulation, students will learn the structures and the
functions of the digestive system.
The teacher will have to prepare stations that contain digestive structures. At each
station, students will be required to perform a specific task to their “food” before
they move to the next phase in the digestive sequence. Once the simulation is
completed students will answer questions in cooperative groups before class
discussion.
Materials:





3 X 5 index card for each student or pair of students
4 pairs of scissors
Station with digestive structure
Structure/Function Cards
Student Instruction Cards
TAKS Objective 2
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Biology
Stations:
Digestive
Structure
Construction
Picture of Mouth
with tongue that
lifts
Written Function
Food digestion begins
Physical and Chemical
Mouth
4” dryer exhaust
vent hose
Esophagus
Hot water bottle
with ends
removed. Have
scissors inside
Digests Starch
w/Enzyme
SALVARY AMYLASE
Transports food to
stomach for further
digestion
Liver/Gall
Bladder/Pancreas
Pass food through by
peristaltic motion to finally
pass through the CARDIAC
SPHINCTER which
connects the esophagus to
the stomach
Chemical
Digests Protein
w/PEPSIN
Green balloon
with scissors
attached by string
Digest food by tearing into
2 equal pieces
Continued food
digestion.
Acidic pH from HCl
Stomach
Student Directions
Cut only one piece of your
food into 2 equal pieces to
continue digestion.
GASTRIN - horomone
that causes the secretion
of gastric juices in the
stomach
GALL BLADDER Breaking down of fat by
emulsion. Liver
produces bile, bile is
stored in the gall bladder
Cut the two smaller pieces
that have been digested into
2 equal halves. You should
now have 4 smaller pieces
Digests Fat
that should now pass though
PYLORIC SPHINCTER so
CHOLECYSTOKININ that nutrients can leave the
stomach and enter the next
(CCK)- intestinal wall
step in digestion.
releases this hormone to
signal the gall bladder to
release bile and the
TAKS Objective 2
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Biology
pancreas to release
digestive enzymes
PANCREAS (Endocrine and Exocrine
function) produces
enzymes need to finish
digesting the main
organic foods. It also
produces insulin.
SECRETIN-intestinal
wall releases this
hormone to signal
pancreas to release a
basic solution to
neutralize the acid.
ENTEROGESTRONEintestinal wall secretes
this hormone to slow
down peristalsis
Inside a clear
garbage bag have
a basket ball net
with scissor
inside
Small Intestine
Further digestion of all
nutrients (carbohydrates,
proteins, lipids) and
maximum absorption of
nutrients, vitamins and
minerals into blood
stream.
Cut the 4 smaller pieces into
8 smaller nutrients. Place
all food particles into the
mesh
bag. Push nutrients
1. Duodenum (1st- 25
through the mesh bag into
cm)
the clear garbage bag.
- when acid chyme
ONLY the pieces that fit
enters this area it triggers
without folding or bending
the liver/gall
will remain at this station.
bladder/pancreas to
Take the larger pieces of
secrete their digestive
food to the next station.
juices
2. Jejunum
3. Ileum
VILLI – small finger-
TAKS Objective 2
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Biology
like projections that
increase the surface area
MICROVILLI – even
smaller finger-like
projections on the VILLI
LACTEAL – large
lymph vessel found on
each villus (Absorbs
FAT)
Place a large
paper cylinder
inside a bowl.
Place scissors
inside.
Large Intestine
CAPILLARIES – small
blood vessels found on
each villus (Absorbs all
nutrients EXCEPT Fat)
Absorbs water and
minerals
CECUM – T junction
that connects the colon
to the small intestine
From your remaining food,
cut off one corner and leave
in bowl.
APPENDIX – attached
at the end of the cecum.
Rectum
Anus
A slinky atop a
shoebox
Shoebox with
circle cut in the
lid. Slinky
should be placed
on top.
Stores undigested food.
Undigested or absorbed
food travels to anus.
Undigested or absorbed
food leaves the body at
this point.
TAKS Objective 2
page 7
Place your name on the
remaining food and place it
inside the rectum
Leave your undigested food
here.
Biology
EXPLAIN
Complete the Digestion PowerPoint presentation with your student with
discussion and the completion of the following answers.
1. When you cut your “food” what did this represent? Physical Digestion
2. What types of nutrients are digested by each structure?
Mouth- Carbohydrates, Stomach- Proteins and Fats, Small Intestine –
Carbohydrates, Proteins and Fats
3. For each digestive structure, tell me if the food was digested physically,
chemically, or both. Mouth – both, Esophagus – physical, Stomach – both,
Small Intestine – both
4. In what digestive structure are the most nutrients absorbed?
Small Intestine
5. Where does undigested food leave the body? Anus
ELABORATE
Elaboration 1
Ask students which type of cloth they think will absorb the most water. The
student should record the prediction in the science journal.
Materials:
Piece of smooth cotton cloth
Graduated cylinder
Piece of terry cloth
Beakers
Water
Timer or watch with second hand
TAKS Objective 2
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Biology
Procedure:
1. Place smooth cotton cloth and terry cloth of equal length and width into a
bowl of water.
2. Let both cloths soak for 30 seconds.
3. Remove cloths and drain for 20 seconds.
4. Wring out each cloth into different containers.
5. Measure the amount of water in each using a graduated cylinder.
6. Record measurements in your data table.
Data Table
Trial 1
Trial 2
Trial 3
Average
Terry cloth
(ml)
Smooth cloth
(ml)
7. Using your data table make a bar graph to illustrate your results.
Remember to label each axis, title your graph, and include a key.
Elaboration 2
Goldfish Swallowing Story
Student will write a creative story describing what happens to a goldfish in three
distinct parts. Part 1: As it passes your lips to the cardiac sphincter. Part 2: As it
passes through the cardiac sphincter until it reaches the place where the
duodenum becomes the jejunum. Part 3: From the jejunum until it exits the
body.
EVALUATE
TAKS Objective 2
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Biology
1. After completing the digestion simulation, the student will have produced
an identical piece of “food” with their name on it in the “anus.” A grade
of pass/fail will be given for correct procedure during the simulation.
2. Using the text, class notes, website information and class discussion the
learner will produce a labeled sketch in his/her journal that describes the
structures and functions of the digestive system. A grade of pass/fail will
be given.
3. Using the text, information from the website, and class notes, the learner
will demonstrate an understanding of the structures and functions of the
digestive system by creating an informational brochure. A minimum
score of 2 on the rubric is required.
TAKS Objective 2
page 10
Biology
TAKS Objective 2
page 11
Biology
The Universe Within
Digestion and Circulation
1. _________ __________ is a five time Olympics speed skater.
2. What does the speed skater eat on a competition day?
3. What is stage of digestion after chewing?
4. The stomach makes ________ quarts of gastric juice each day.
5. What prevents the stomach from being eaten by stomach acids?
6. Things like _________ and ___________ will destroy the mucous
membrane of the stomach.
7. After leaving the stomach, food goes to the _________ __________.
8. Bile breaks fats into small ______ _________ __ ________.
9. The gall bladder stores ________.
10. Eating too much _______ can cause cholesterol, bile salts, and
pigments to form little falls which become gallstones.
11. What accounts for the brown color of human waste?
12. _____% of human waste is made up of friendly bacteria in the colon.
13. The small intestine is lined with tiny fingerlike projections called
________.
TAKS Objective 2
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Biology
14. Each villus is surrounded by blood __________ where tiny molecules
of food diffuse across the cell membrane and enter the blood for
transportation to cells.
15. The ________ is the largest single organ we have.
16. The liver produces about a __________ proteins every minute. About
half of the body’s dry weight is protein.
17. The liver removes cholesterol and converts it to _____ which is stored
in the gall bladder.
TAKS Objective 2
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Biology
Teachers Film Guide Answers
The Universe Within
Digestion and Circulation
1. Bonnie Blair is a five time Olympics speed skater.
2. What does the speed skater eat on a competition day? A peanut butter
and jelly sandwich
3. What is the first stage one of digestion after chewing? Muscle
contraction
4. The stomach makes 3 quarts of gastric juice each day.
5. What prevents the stomach from being eaten by stomach acids?
Mucus membrane
6. Things like salt and alchohol will destroy the mucous membrane of
the stomach.
7. After leaving the stomach, food goes to the small intestine, the
primary site of absorption.
8. Bile breaks fats into small globules of fat.
9. The gall bladder stores bile.
10. Eating too much fat can cause cholesterol, bile salts, and pigments to
form little falls which become gallstones.
11. What accounts for the brown color of human waste? Bile
TAKS Objective 2
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Biology
12. 25% of human waste is made up of friendly bacteria in the colon.
13. The small intestine is lined with tiny fingerlike projections called villi.
14. Each villus is surrounded by blood vessels where tiny molecules of
food diffuse across the cell membrane and enter the blood for
transportation to cells.
15. The liver is the largest single organ we have.
16. The liver produces about a million proteins every minute. About half
of the body’s dry weight is protein.
17. The liver removes cholesterol and converts it to bile which is stored in
the gall bladder.
TAKS Objective 2
page 15
Biology
Digestion Simulation
Teacher Page
Structure/Function Cards: WORK ON THESE…ADD MORE INFORMATION
MOUTH
This is where digestion will begin. Your teeth
grind your food into smaller particles. The saliva
your mouth produces helps to digest complex
carbohydrates (starches) in our diet, moisten and
protect our mouth from abrasion and kills some
bacteria, while our tongue rolls the food into a
ball for us to swallow. Both physical and
chemical digestion occurs here.
Image: www.anothersite.co.uk
ESOPHAGUS
Before food enters into the esophagus, it must pass
through the pharynx and cause the EPIGLOTTIS to
close off the trachea. The esophagus or food tube is
the pathway that food travels to get to the stomach.
Food will move in a rhythmic motion of smooth
muscle contractions called peristalsis. Once food
passes the CARDIAC SPHINCTER, it will enter
into the stomach
TAKS Objective 2
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Biology
GALL BLADDER
The gall bladder is a digestive system
accessory organ. It is a small organ
behind the stomach attached to the
liver. The liver makes bile a chemical
that is stored in the gall bladder. The
gall bladder releases the bile to assist in
the digestion of fat. This process is
called emulsification of fat.
Image: www.smallscars.com
STOMACH
Digestion will continue within the
stomach with an internal acidic
environment of pH 1-2. The acidic
(HCl) stomach will churn with peristaltic
contractions to continue the processing
of proteins by activating the enzyme
PEPSIN. When the chyme reaches the
PYLORIC SPHINCTER it is ready to
enter into the small intestine
Image: www.sciencebob.com
TAKS Objective 2
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Biology
SMALL INTESTINE
Digestion and ABSORPTION occurs within
this structure. The small intestine has many
hormones and enzymes that assist in the
digestion and absorption of carbohydrates,
lipids and proteins. These nutrients can now
be easily absorbed into the blood stream to
be transported throughout the body. Most of
the body’s nutrients are absorbed by this
structure.
Image: http://www.uen.org
LARGE INTESTINE
The large intestine surrounds the small
intestine. The primary function of the large
intestine is to absorb water and minerals and
transport undigested particles into the rectum.
Image: www.sghhealth4u.com
TAKS Objective 2
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Biology
THE RECTUM
Found at the bottom of the colon (large
intestine). This area of the digestive
tract holds undigested food or waste
until it passes out of the anus.
Image: www.achosp.org
THE ANUS
This is the last structure of
the digestive tract.
Undigested food uses this
opening to exit from the
body.
TAKS Objective 2
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Biology
Student Instruction Cards:
MOUTH:
Place your food under the tongue.
Digest your food by tearing it into 2 equal
pieces.
ESOPHAGUS:
Allow your two pieces of food to pass through
by peristaltic motion.
STOMACH:
Cut only 1 piece of your food into 2 equal pieces
to continue digestion.
TAKS Objective 2
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Biology
GALL BLADDER:
Cut the two smaller pieces that were digested in
the stomach into 2 equal halves. You should
have 4 smaller pieces of food and 1 large piece
of food.
SMALL INTESTINE:
Cut the 4 smaller pieces into 8 smaller nutrients.
Place all food particles into the mesh bag. Push
nutrients through the mesh bag into the clear
garbage bag. ONLY the pieces that fit without
folding, bending or forcing will remain at this
station. Take the larger pieces of food to the
next station.
LARGE INTESTINE:
From your remaining food, cut off one corner
and leave it in the bowl.
TAKS Objective 2
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Biology
RECTUM:
Place your name on the remaining food and
place it inside the rectum.
ANUS:
Leave your undigested food here.
TAKS Objective 2
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Biology
Digestion Simulation
Overview:
You will learn about the structures and functions of the digestive system as you
participate in this simulation. Your teacher has to prepared lab stations that
contain digestive structures. At each station, you will be required to perform a
specific task to your “food” before you can move to the next phase in the
digestive sequence. Once the simulation is completed, you will have an
understanding of the digestive process.
Materials:


3 X 5 index card (food)
Writing utensil
Procedure:
1. Take your piece of “food” to the first station.
2. At each digestive station there are specific directions concerning the digestion
of your food.
3. Carefully follow the directions at each digestion station.
4. Once at the end of the digestive tract answer the questions that follow.
TAKS Objective 2
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Biology
Question:
1. When you cut your “food” what did this represent?
2. What types of nutrients are digested by each structure?
3. For each digestive structure, tell me if the food was digested physically,
chemically, or both.
4. In what digestive structure are the most nutrients absorbed?
5. Where does undigested food leave the body?
TAKS Objective 2
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Biology
Digestion Website Exploration
Directions:

Visit the following website:
http://www.medtropolis.com/VBody.asp

Click on English or Spanish

Now click on “Digestive System”

A new menu will appear and you will need to click on “Guided Tour”

Listen and read along with the narration. While learning the new information,
answer the questions that follow:
1. Where does digestion begin?
2. List four organs of the digestive system.
3. What chemical in the mouth actually begins the process of
digestion?
4. Approximately, how long is the small intestine?
5. What organ of the digestive tract absorbs more nutrients than
any other organ?
6. What nutrient does the mouth begin digesting?
7. What nutrient does the stomach begin digesting?
TAKS Objective 2
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Biology
8. What digestive structure has little or no digestive function?
9. What is another name for the large intestine?
10. What is the overall function of the digestive system?
11. Now see if you can organize your digestive organs. Go back to
the “Organize Your Organs” game and place your digestive
tract in the correct order. When you have it in the correct
order, tell your teacher.
12. Using the text, class notes, website information and class
discussion produce a labeled sketch in your journal that
describes the structures and functions of the digestive system.
TAKS Objective 2
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Biology
Small Intestine Simulation
Which type of cloth do you think will absorb the most water? Record the
prediction in your science journal.
Materials:
Piece of smooth cotton cloth
Graduated cylinder
Piece of terry cloth
Beakers
Water
Timer or watch with second hand
Procedure:
1. Place smooth cotton cloth and terry cloth of equal length and width into a
bowl of water.
2. Let both cloths soak for 30 seconds.
3. Remove cloths and drain for 20 seconds.
4. Wring out each cloth into different containers.
5. Measure the amount of water in each using a graduated cylinder.
6. Record measurements in your data table.
Data Table
Trial 1
Trial 2
Trial 3
Average
Terry cloth
(ml)
Smooth cloth
(ml)
TAKS Objective 2
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Biology
7. Using your data table make a bar graph to illustrate your results.
Remember to label each axis, title your graph, and include a key.
Class Discussion Questions:
1. Which cloth is similar to the inside of the small intestine?
Explain why.
2. How would this help the small intestine in its absorption of food?
3. What similarities can you cite between the villi of the small intestine, the
alveoli of the lungs, and the nephrons of the kidneys?
4. List one limitation of using this model as a comparison to the villi in the
small intestine.
5. Which systems are interacting together in this learning activity? .
TAKS Objective 2
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Biology
Goldfish Swallowing
The year is 1958. The place is “State University.” You are a college
student trying to make your name with the local group. That’s right!!!
It’s goldfish swallowing time. So you grab a scaly orange osteichthyes
and gulp it down.
Part 1: Describe what happens to the fish from the moment it passes
your lips until it reaches the cardiac sphincter.
Part 2: Describe what happens to the fish from the moment it passes
though the cardiac sphincter until it reaches the place where the
duodenum becomes the jejunum.
Part 3: Describe what happens to the fish from the jejunum until it
exits the body.
Notes:







You must describe every structure the fish touches or passes
through.
Every organ or gland associated with digestion must be
described.
Use your creative ability. The more creative the better.
Pick a creative point of view…perhaps, write it as if you are the
fish.
Write a rough draft in pencil and staple it to the back of your
final draft.
PROOFREAD!!!
Your final draft MUST BE TYPED!!!
TAKS Objective 2
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Biology
Nutrition/Macromolecues
5 E’s
ENGAGE
Show student various weight loss ads and claims or show a few clips from the
movie Super Size Me. Discuss that if there were a magic pill that obesity would
not be at epidemic proportions in the US. Our body needs essential nutrients for
growth, health and overall well-being. We cannot deny our body these essentials
and be healthy.
EXPLORE
Exploration 1
Identifying Organic Compounds Lab
Students will test common foods for the presence of carbohydrates,
lipids, proteins and nucleic acids
Exploration 2
Calorimetry Lab
By burning a piece of food, students will determine the amount of
chemical energy (calories) that are present within the tested foods.
Students will study various types of food with different proportions of
protein, fat, and carbohydrates to see how much energy (calories) they
release.
TAKS Objective 2
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Biology
EXPLAIN
Complete the Nutrition/Macromolecules PowerPoint presentation. During the
presentation students should be able to discuss and complete the following
type of questions: REWRITE QUESTIONS
ELABORATE
Elaboration 1
Investigating Carbohydrates, Lipids, Proteins, and Nucleic Acids
Students will investigate the structure and formation of each type of
macromolecule using a hands-on manipulative.
Elaboration 2
Food Label Analysis
Have students bring in various types of food items in their original
containers. Students will view these various food labels and analyze
the nutritional value of various food items.
EVALUATE
1. Using the provided handout, students will correctly identify 3 of 4
macromolecules found in various common foods.
2. Using a hand-on manipulative, students will investigate the structure and
correctly construct each of the four types of macromolecules.
3. After identifying essential nutrients, students will analyze nutrition labels
and make judgments on the overall nutritional value of the products. A
grade of pass/fail will the given.
TAKS Objective 2
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Biology
TAKS Objective 2
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Biology
Identifying Organic Compounds
Introduction:
The most common organic compounds found in living organisms are lipids,
carbohydrates, proteins, and nucleic acids. Common foods, which often consist
of plant materials or substances, derived from animals, are also combinations of
these organic compounds. Substances called indicators can be used to test for the
presence of organic compounds. An indicator is a substance that changes color in
the presence of a particular compound. In this investigation, you will use several
indicators o test for the presence of lipids, carbohydrates, and protein in various
everyday foods.
Read the entire investigation and complete the following questions. Before
you can begin the lab experience your teacher must verify that the pre-lab
discussion questions have been completed and answered accurately.
Pre-Lab Discussion Questions:
What is an indicator? How are indicators used in this experiment?
What is the purpose of using distilled water as one of your test substances?
What is the controlled variable in Part C?
What is the purpose of washing the test tubes thoroughly?
You have added Sudan III stain to each of the test tubes. What change indicates
the presence of lipids?
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Biology
Materials
10 test tubes
Test-tube rack
Test-tube holder
Masking tape
Bunsen burner or hot plate
Iodine solution
20 mL honey solution
20 mL egg white and water mixture
20 mL corn oil
20 mL lettuce and water mixture
20 mL gelatin and water mixture
20 mL melted butter
20 mL potato and water mixture
20 mL apple juice and water mixture
20 mL distilled water
20 mL unknown substance
paper towels
600-mL beaker
brown paper bag
Sudan III stain
Biuret reagent
Benedict’s solution
plastic gloves
glass-marking pen
10 dropper pipettes
10 mL graduated cylinder
Procedures:
1. Obtain 9 test tubes and place them in a test tub rack. Use masking tape to
make labels for each test tube. As shown in Figure 1, write the name of
different food samples on each making tape label. Label the ninth test tube
“distilled water,” this will act as your control group.
2. Use the graduated cylinder to transfer 5 mL of distilled water into the test tube
labeled “distilled water.” Use a glass-marking pen to mark the test tube at the
level of the water. Mark the other test tubes in the test-tube rack at the same
level.
3. Use a separate dropper pipette to fill each of the other test tubes with 5 mL of
the substance indicated on the masking-tape label. Add 5 drops of Sudan III
stain to each test tube. Sudan III stain will dissolve in lipids and stain them
red.
4. Gently shake the contents of each test tube. CAUTION: Use extreme care
when handing Sudan III to avoid staining hands and clothing. In the Data
Table, record the color changes and place a check mark next to those
substances testing positively for lipids.
5. Wash the test tubes thoroughly.
TAKS Objective 2
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Biology
Honey
Egg White
Corn Oil
Lettuce
Gelatin
Butter
Potato
Apple Juice
Distilled
Water
Unknown
Figure 2
6. For another test for lipids, divide a piece of brown paper bag into 10 equal
sections. In each section, write the name of one test-substance, as shown in
Figure 2.
7. In each section, place a small drop of the identified food on to the brown
paper. With a paper towel, wipe off any excess pieces of ood that may stick to
the paper. Set the paper aside until the spots appear dry – about 10 to 15
minutes.
8. Hold the piece of brown paper up to a bright light or window. You will notice
that some foods leave a translucent spot on the brown paper. The translucent
spot indicates the presence of lipids.
TAKS Objective 2
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Biology
Part B. Testing for Carbohydrates
1. Sugars and starches are two common types of carbohydrates. To test for
starch (polysaccharides), use the same dropper pipettes to refill each
cleaned test tube with 5 mL of the substance indicated on the maskingtape label. Add 6 drops of iodine solution to each test tube. Iodine will
change color from yellow-brown to blue-black in the presence of starch.
2. Again using extreme CAUTION, gently shake the contents of the test
tube. In the Data Table, record any color changes and place a check mark
next to those substances testing positive for starch.
3. Wash the test tubes thoroughly.
4. For a simple sugar (monosaccharide) test, set up a hot-water bath. Half
fill the beaker with tap water. Heat the water to a gentle boil. CAUTION:
Use extreme care when working with hot water. Do not let the water
splash onto your hands.
5. While the water bath is heating, fill each cleaned test tube with 5 mL of
the substance indicated o the masking-tape label. Add 10 drops of
Benedict’s solution to each test tube. When heated, Benedict’s solution
will change color from blue to green, yellow, orange, or red in the
presence of a simple sugar, or monosaccharide.
6. Using CAUTION, gently shake the contents of each test tube.
7. Place the test tubes in the hot-water bath. Heat the test tubes for 3-5
minutes. With the test tube holder, remove the test tubes form the hotwater bath and place them back in the test tube rack. CAUTION: Never
touch hot test tubes with your bare hands. Always use a test tube holder to
handle hot test tubes. In the Data Table, record any color changes and
place a check mark next to any substances that test positive for a simple
sugar.
8. After they have cooled, wash the test tubes thoroughly.
TAKS Objective 2
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Biology
Part C. Test for Proteins
1. Put 5 mL of the appropriate substances in each labeled test tube. Add 5
drops of biuret reagent to teach test tube. CAUTION: Biuret reagent
contains sodium hydroxide, a strong base. If you splash any reagent on
yourself, wash it off immediately with water. Call your teacher for
assistance.
2. Gently shake the contents of each test tube. Biuret reagent changes color
from yellow to blue-violet in the presence of protein. In the Data Table,
record any changes in color and place a check mark next to any substances
that test positively for proteins.
3. Wash test tubes thoroughly.
Part D. Testing an Unknown Substance for Organic Compounds
1. Obtain a sample of an unknown substance from your teacher and pour it
into the remaining test tube. Repeat the test described in Parts A, B, and C
of the procedure to determine the main organic compounds in your
sample. Record your results in the Data Table.
2. Wash the test tube thoroughly.
TAKS Objective 2
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Biology
Data Table
Lipid Test
Substance
Sudan
Color
Lipids
Present
(X)
Carbohydrate Test
Iodine
Color
Starches
Present
Benedicts’s
Color
(X)
Protein Test
Sugars
Present
Biuret Proteins
Color Present
(X)
(X)
Honey
Egg
White
Corn Oil
Lettuce
Gelatin
Butter
Potato
Apple
Juice
Distilled
Water
Unknown
TAKS Objective 2
page 38
Biology
Analysis and Conclusions
1. Which test substances contain lipids?
2. Which test substances contain starch (polysaccharides)?
3. Which test substances contain simple sugars (monosaccharides)?
4. Which test substances contain protein?
5. Which test substances did not test positive for any of the organic
compounds?
6. People with diabetes are instructed to avoid foods that are rich in
carbohydrates. How could you observations in this investigation help you
decide whether a food should be served to a person with diabetes?
7. Your brown lunch bag has a large, translucent spot on the bottom. What
explanation could you give for this occurrence?
TAKS Objective 2
page 39
Biology
Calorimetry
Introduction:
Plants have evolved processes that convert light energy into the chemical bonds of
complex molecules. The chemical bonds in carbohydrates, fats, and proteins store
energy until needed by the plant. The plant can then release by breaking the
appropriate chemical bonds. Every animal maintain its life processes by
consuming complex molecules that store energy. The processes plants and
animals we eat as foods contain varying amounts of energy; these foods will
release varying amounts of energy when they are used by cells. Within our
bodies the energy is released slowly by a series of chemical reactions.
Read the entire investigation and complete the following questions. Before
you can begin the lab experience your teacher must verify that the prelab
discussion questions have been completed and answered accurately.
Pre-Lab Discussion Questions:
1. The calorie is a measurement of ___________________ and light.
2. Define calorie:
3. True or False: Foods with few calories produce the most heat.
4. In this investigation, why did we choose to use distilled water?
5. Why should you take the initial temperature of the water?
6. The test tube should be raised how many cm above the food sample?
7. When is the mass of the food sample taken?
8. When is the temperature of the water taken?
TAKS Objective 2
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Biology
Pre-Lab Preparation:
By burning pieces of food, the chemical energy stored in molecular bonds is
released as heat and light. The heat can be measured in units called calories. A
calorie is the amount of heat (energy) required to increase the temperature of one
gram of water by one degree C. This process is the basis of the technique of
calorimetry.
The more calories a food contains, the more heat is given off when burned. Foods
high in calories will release large amounts of energy. One gram of a protein will
release far fewer calories than one gram of fat. You will study foods with
different proportions of proteins, fats, and carbohydrates to see how much energy
(calories) they release.
Materials:
Test Foods
Test Tube (18 X 150mm)
Balance
25mL Graduated Cylinder
Utility Clamp
Large cork with pin
Ring Stand
Matches
Thermometer
Distilled Water
Figure 1
Procedure:
1. Assemble the ring stand and clamp so that a test tube placed in the clamp will
be one cm above the food sample (Figure 1)
2. Place 15.0 mL of distilled water in the test tube and put the test tube in the
clamp. Place the thermometer in the test tube.
3. Obtain a 1 to 3 g sample of test food number 1. Find the mass of the test food
sample to the nearest 0.01 g (two decimal places), and record its name and
mass in the Data Table.
4. Measure the temperature of the water in the test tube to the nearest 0.5 degrees
C and record in the Data Table as initial water temperature.
5. Use the pin to affix the sample to the cork. Place the cork on the table away
from the test tube. Then strike a match and set the food on fire. Immediately
move the sample under the test tube. Gently stir the water with the
thermometer, using an up and down motion.
TAKS Objective 2
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Biology
6. After the food sample is completely burned, measure the temperature of the
water again to the nearest 0.5 degrees C, and record in the Data Table as final
water temperature. Be sure to watch the thermometer carefully, to catch
the highest temperature reached.
7. Find the mass of the sample remaining to the nearest 0.01 g and record in the
Data Table as mass of sample after burning (ash weight).
Test
food
#
Food Name
Mass of
Sample
BEFORE
Burning
GRAMS
Mass of
Sample
AFTER
Burning in
GRAMS
TAKS Objective 2
Initial Water
Temperature
°C
page 42
Final Water
Temperature
°C
Biology
Kilocalories
per gram of
sample
Kcal/g
Calculations:
1. Subtract the mass of the sample after burning (ash weight) from the mass of
the sample before burning. This is the change in mass.
Change in mass =
________________ g
2. Calculate the change in temperature for the water by subtracting the initial
water temperature from the final water temperature.
Change in water temperature =
______°C
3. To estimate the calories in the food sample you will need the mass of the
water you heated. By definition the density of water is 1g/mL, so 1 mL of
water has a mass of 1g. The 15.0 mL of water you used would be 15.0 g.
Mass of water = 15.0 g
The following formula will calculate Kilocalories (Kcal). Once kilocalorie =
1000 calories.
The specific heat of water is 1 kilocalorie/Kg deg C. So the formula would
look like this.
You will see that all units of measurement except kilocalorie cancel each other
out of the equation. Everything is already in the equation except your change
in temperature for the water. Put in our change in temperature and work the
calculation. You now have the total kilocalories of energy given off by the
food sample.
Energy given off by sample
= ____________Kcal
4. Calculate the kilocalories per gram of the food sample. This is the total
kilocalories divided by the change in mass of the sample. The unit will be
Kilocalories/gram.
Kilocalories per gram of
sample = __________Kcal/g
TAKS Objective 2
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Biology
Now repeat the procedure with the next food sample. You may collect the
data for all the samples, and then do the calculations. Use a clean test tube
each time.
Compare the answer to step 11 for all the food samples.
Conclusion: Write a brief overview of your findings.
TAKS Objective 2
page 44
Biology
Investigating Carbohydrates
Introduction: Carbohydrates contain carbon (C), hydrogen (H), and oxygen (O).
They are referred to as sugars or saccharides. The many different types of sugars
haven grouped into three main categories: monosaccharides, disaccharides, and
polysaccharides. During this lab investigation, you will be investigating the
structure and formation of carbohydrates.
Materials:
Paper carbohydrate models
construction paper
Scissors
glue
Pencil
Procedure:
Part I: Monosaccharides
Examine the structural formulas and corresponding models on your model
sheet. We will use these paper models to illustrate the various types of
carbohydrates and the chemical reactions necessary to join them together.
1. What three elements are present in monosaccharides?
2. How many atoms of carbon are present in monosaccharides?
3. Write the molecular formula for glucose, putting the elements in this order:
carbon, hydrogen, and then oxygen.
4. Write the molecular formula for fructose.
5. Write the molecular formula for galactose.
TAKS Objective 2
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Biology
6. Compare the number of hydrogen atoms to the number of oxygen atoms in
each of the monosaccharides. What is the ratio of hydrogen to oxygen to
glucose?
In fructose?
In galactose?
7. How do the ratios of hydrogen to oxygen compare in the three
monosaccharides compare to each other?
8. Is the arrangement of carbon, hydrogen, and oxygen atoms the same in the
three monosaccharides?
Part II: Disaccharides
Two monosaccharide molecules can join chemically to form a disaccharide.
By joining a glucose molecule with another glucose molecule, a disaccharide
called maltose is formed. By joining a glucose molecule with a fructose
molecule, a different disaccharide called sucrose is formed.
Cut out a glucose and a fructose paper model from the sheet provided. CUT
ALONG SOLID LINES ONLY! Attempt to join the molecules together like
the pieces of a puzzle.
9. Will the two molecules fit together to form a sucrose molecule?_________
In order to join these together like puzzle pieces, you must remove an OH- from
one molecule and an H+ from the other. Cut along the dotted lines to do this,
keeping the OH- and H+ pieces for later. Now that there are “tabs”, the pieces will
fit together like puzzle pieces.
Now try to fit the OH- and the H+ together. Do they fit? ____________
Glue these pieces to construction paper and label each with the appropriate name
and molecular formula.
10. What molecule is formed when the OH- and the H+ are fit together?
Remember that you removed the OH- and the H+ from the molecules in order to
get them to fit together. In fact, whenever saccharides combine, water molecules
must be removed. This type of reaction is there called, dehydration synthesis.
11. Why is “dehydration synthesis” a fitting name for this process?
TAKS Objective 2
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Biology
12. Write the molecular formula for maltose:________________________
13. Is the ratio of hydrogen to oxygen the same in sucrose and
maltose?______________
14. Is the ratio the same in glucose and fructose?_________________
15. How many monosaccharides are needed to construct a disaccharide
molecule?____________
16. What groups must you remove to form the “bonds” of the puzzle pieces?
17. Is this the same reaction used to form the disaccharides?_____________
18. Compare the ratio of hydrogen to oxygen in monosaccharides, disaccharides,
and polysaccharides:
19. Break apart your sucrose molecule into glucose and fructose. Replace the
missing OH- and H+ groups. What molecule did you have to split apart to
give the OH- and H+ groups? _________________
20. When carbohydrates are broken down, water molecules must be broken down,
or split, into OH- and H+. Thus, the process of breaking down carbohydrates
into simple sugars is called “hydrolysis” – “Hydro” = water, “lysis” = to split.
Interpreting:
1. Write the molecular formula for glucose. _____________________
2. Write the molecular formula for galactose. ____________________
3. Write the molecular formula for fructose______________________
4. How do glucose, galactose, and fructose differ?
5. What is a monosaccharide?
TAKS Objective 2
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Biology
6. What is a disaccharide?
7. Maltose is a disaccharide. Describe how it is formed:
8. Why is water produced in the formation of a disaccharide?
9. How is maltose broken down?
10. What is a polysaccharide?
TAKS Objective 2
page 48
Biology
Carbohydrates
TAKS Objective 2
page 49
Biology
Investigating Lipids
Introduction:
Another important source of energy for life is the fats and lipids. Like
carbohydrates, fats are made up of simpler units or monomers. The monomers of
lipids are called glycerol, a type of alcohol, and fatty acids. The properties of
different fats depend on the types of fatty acids that make them up. A fat may
contain fatty acids that are all the same or all different. The smaller the fatty acid
molecules, the easier the fat will melt. During digestion with the help of bile, an
enzyme called lipase which comes from the pancreas, splits fats into fatty acids
and glycerol. Food is often stored in animals and plant seeds as fat, because they
can store more energy more efficiently than carbohydrates and proteins. This is
due to their high number of carbon-hydrogen bonds which store more energy than
carbon-oxygen bonds. In this laboratory investigation, you will examine the
structural characteristics of lipids and relate this structure to chemical and
physical properties.
Materials:
Graphic of fatty acids and models
glue
Scissors
construction paper
Procedure:
1. Examine the structural formula of glycerol. What elements are present in
glycerol?
2. Are there any elements in glycerol that are not in carbohydrates? If so, which
elements?
3. Write the molecular formula for glycerol:
4. Are there twice as many hydrogen atoms as oxygen atoms?
5. Examine the structural formulas for the three fatty acids. Lauric Acid, Butyric
Acid, and Caproic Acid. What elements are present in all fatty acids?
6. Write the molecular formula for Butyric Acid:
For Caproic Acid:
For Lauric Acid:
TAKS Objective 2
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Biology
7. How do the number of hydrogen atoms compare to the number of oxygen
atoms in Butyric Acid:
In Caproic Acid:
In Lauric Acid:
8. How many oxygen atoms are present in each fatty acid?
9. Note the end of the Butyric Acid containing the oxygen atoms. This special
arrangement of carbon, hydrogen, and oxygen is called an organic acid. Its
name is carboxylic acid or a “carboxyl group” for short. Notice the double
bond between the C and O. Is the carboxyl group present in all three fatty
acids?____________ Circle the carboxyl groups.
10. Describe a similarity between glycerol and fatty acids:
11. Do fatty acids and glycerol both contain a carboxyl group?
12. Remove and save the three OH- ends from the glycerol molecule and the three
H- ends from the fatty acid models at the bottom of the page for formulas.
Now join the molecules to form a triglyceride. Will the molecules fit together
like pieces of a puzzle?_________
13. How many glycerol molecules are needed to form a triglyceride?
14. How many fatty acid molecules are needed to form a triglyceride?
15. Why is this molecule called a triglyceride?
16. Join the left over OH- and H+ ends from the models. How many water
molecules are formed?
17. Write a word equation telling what happens:
18. What is this type of reaction called?
19. Look at the structural formula for Linolenic Acid. How does it differ from the
other three fatty acids you have investigated in this activity?
20. Linolenic Acid is called an unsaturated fatty acid. What do you think this
means?
TAKS Objective 2
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Biology
Interpreting:
1. Which type of fatty acid would you find in saturated fats?
2. Which type of fats, saturated or unsaturated, are considered a health
hazard?
3. What do they cause?
4. Which type of organisms produce saturated fats?
5. Which types of organisms produce unsaturated fats?
6. Which type of fat is liquid at room temperature?
7. Which type of fat is solid at room temperature?
8. When digestion of fats occurs, they are broken down into fatty acids and
glycerol. Besides the enzymes needed to start this reaction, what other
substance must be present?
9. Suggest a reason why seeds might need to sore energy as fats rather than
as carbohydrates:
10. Suggest a reason why carbon-hydrogen bonds can store more energy than
carbon-oxygen bonds:
11. If you were to chemically analyze a fatty acid molecule in the lab, what
element would you find in the greatest abundance?
In the least abundance?
TAKS Objective 2
page 52
Biology
Lipids
TAKS Objective 2
page 53
Biology
Investigating Proteins
Introduction:
What organic compounds were formed on earth before life emerged? How did
life on earth begin? Scientists used to wonder whether the primitive conditions of
early earth could have supported the formation of the organic building blocks of
life. To test their hypothesis, they created what they thought to be a close
approximation to the earth’s primordial atmospheric conditions. These conditions
included methane, hydrogen, and ammonia gases, heat, rain, and flashes of
lightning. They circulated these together for about a week, then analyzed the
contents and found that some of the atoms had recombined to form amino acids.
Today we know that amino acids are the building blocs, or monomers, of proteins.
Scientists believe that as these simple organic compounds accumulated in the
oceans, some combined to form larger and more complex molecules, namely, the
proteins.
Proteins are the most abundant organic compounds found in every living cell.
They are complex molecules composed of different combinations of 20 different
amino acids. Even though there are only 20 amino acids, they can combine in
many ways to form thousands of different types of proteins. In this lab
investigation you will examine the structure of amino acids.
Materials:
Protein graphic
Construction paper
Scissors
Glue
Procedure:
1. Examine the structural formulas of the four representative amino acids. Name
the four elements found in all amino acids:
2. Write the molecular formulas for the following, listing C, H, O, then N:
Glycine:_______________
Alanine:_______________
Valine:________________
TAKS Objective 2
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Biology
3. How do the molecular formulas for all the amino acids differ?
4. What group do you find in the amino acids that was also present in the fatty
acids?_______ What is its name?_______________
In each of the amino acids, circle this group in red.
5. Find the carbon atom that is directly to the left of the carboxyl group.
Locating this central carbon will help you to identify the other components of
an amino acid. The amino group is composed of a nitrogen atom bonded to
two hydrogen atoms. The nitrogen atom will always be connected directly to
the central carbon. Find the amino groups in each of the amino acids and
circle them in blue.
6. Do fatty acids have an amino group?
7. Do carbohydrates have an amino group?
8. Do carbohydrates have a carboxylic acid group?
9. What element is found in amino acid that is not found in carbohydrates or
lipids?
10. Locate the central carbon atom in each amino acid. Bonded directly on top of
it is a hydrogen atom. Circle the hydrogen atoms in each of the amino acids
in green. All amino acids then, contain the same three basic parts arranged
around a central carbon. Name these three parts:
11. The central carbon still has one more bond to be used up. Look at the models
of the amino acids. List the remaining components attached to the central
carbon atoms in each (List C, then H):
Glycine:________________
Alanine:________________
Valine:_________________
Threonine:______________
In each case, this last group is called the “R” group. It is different for each of
the amino acids. How many different “R” groups can there be?___________
TAKS Objective 2
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Biology
12. Cut out the models of the amino acids by cutting along the solid lines. Can
the amino acid model fit together like the pieces of a puzzle?________ (Your
teacher may want you to paste these molecules on construction paper for
notes.)
13. What other groups of atoms must be removed to allow the molecules to join?
14. Remove as many of these as necessary, saving the pieces, to join the three
amino acids and join these together. What molecule do they form?
15. How many of these molecules are formed?
16. What is this type of reaction called?
17. All proteins are composed of only the 20 amino acids, yet there are thousands
of different kinds of proteins. How do these proteins differ from one another?
TAKS Objective 2
page 56
Biology
AMINO ACIDS
TAKS Objective 2
page 57
Biology
Investigating Nucleic Acids
Introduction:
You will continue to investigate and identify the components of nucleic acids.
Procedure:
1. Color each part of the nucleotide according to the following key:
a. Deoxyribose:
red
b. Ribose:
blue
c. Adenine:
pink
d. Thymine:
purple
e. Uracil:
brown
f. Cytosine:
yellow
g. Guanine:
orange
h. Phosphoric acid:
green
2. Cut out the nucleotide models along the solid lines
3. Complete right side of DNA molecule by matching the bases of the
nucleotides in the following order:
DNA
Left Side
G-?
A-?
C-?
T-?
A-?
Tape these together so they make a ladder
TAKS Objective 2
page 58
Biology
TAKS Objective 2
page 59
Biology
TAKS Objective 2
page 60
Biology
Food Label Analysis
Image: http://www.nhlbi.nih.gov/chd/Tipsheets/images/nutrition.jpg
TAKS Objective 2
page 61
Biology
Enzymes
5 E’s
ENGAGE
What do you think would happen to digestion if the gall bladder is blocked?
Can you live without a gall bladder?
What do you think would happen to the digestive process if your stomach had a
neutral pH?
What if your stomach had a basic pH?
If you have an abnormal body temperature, what do you think the overall affect to
digestion would be?
EXPLORE
Exploration 1
A Study of Biochemical Reactions
Student will observe the activity of catalase in two substances, both of which
break down hydrogen peroxide. One of these is a plant, potato. The other is
animal tissue, liver. Both organic sources of the enzyme, catalase, an organic
compound.
TAKS Objective 2
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Biology
Exploration 2
Hands on Enzyme Manipulative
Toying with Enzyme Catalysis: The learner will be able to identify the
components of a typical catalytic cycle and describe the relationship among the
enzyme, substrate, and active site.
Sandra Gonzales (John Jay High School), Barbara Larger (O’Connor High School), and Debbie
Richards (Bryan High School)
EXPLAIN
Complete the Enzyme PowerPoint presentation. During the presentation,
students should be able to discuss and complete the following type of
questions: WRITE QUESTIONS
ELABORATE
Investigating Digestive Process
Science Kit and Boreal www.sciencekit.com SKU - WW4705200
Use this Science Kit and Boreal lab kit to help students understand that during the
digestive process, certain enzymes in various parts of the body work to break
down food into a form the body can use. In this lab, students re-create this
process, gaining a valuable understanding of the actions of different enzymes in
their own bodies. They also manipulate such variables as pH and temperature to
see how these features affect the enzymes. In addition, they determine where in
the body starches, proteins and fats are digested; and test for digestion byproducts.
TAKS Objective 2
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Biology
EVALUATE
See blackline masters.
TAKS Objective 2
page 64
Biology
TAKS Objective 2
page 65
Biology
Enzyme Catalysis
Introduction:
Hydrogen peroxide (H2O2) is a highly active chemical often used for bleaching. It
is sold as a 3% solution in water. Within cells hydrogen peroxide is formed
continually as a by-product of biochemical processes. Because H2O2 is toxic
(poisonous) to cells, it would soon kill them if not immediately removed or
broken down.
In this investigation you will observe the activity of two substances, both of which
break down hydrogen peroxide. One of these is manganese dioxide, an inorganic
catalyst. The other is an enzyme, catalase, an organic compound.
Materials:
3 pieces fresh liver, each about 6 mm in diameter
Beaker
Fresh potato
Scalpel
100 mL 3% hydrogen peroxide solution (H2O2)
Forceps
Manganese dioxide powder (MgO2)
Test-tube rack
Fine sand
Mortar and pestle
10 test tubes, 13 x 100 mm
Hot Plate
Graduated cylinder, 10 mL
Glass-marking crayon
Procedure:
1. Arrange the test tubes in the rack and number them from 1 to 10. Pour 2 mL
water into each of Tubes 1 and 2.
2. Pour 2 mL hydrogen peroxide (H2O2) solution into each of the other tubes
(DO NOT place H2O2 into Tubes 1 and 2). After each of the following steps,
record your observations. Compare observations on different tubes
frequently.
3. Into Tube 1 sprinkle a small amount (about half a scalpel bladeful) of
manganese dioxide (MnO2) powder.
4. Repeat for Tubes 2 and 3.
TAKS Objective 2
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Biology
5. Place Tube 1 in boiling water for a few minutes. Then pour its contents into
Tube 4.
6. Using forceps, select a small piece of fresh liver and drop it into Tube 5.
7. Place another piece of fresh liver (the same size) into a mortar. Add a little
fine sand and grind the liver. Transfer the resulting mixture to Tube 6. Wash
the mortar thoroughly.
8. Place a 3rd piece of liver in boiling water for a few minutes. Drop the boiled
liver into Tube 7.
9. Into Tube 8 sprinkle the same amount of sand as of the manganese dioxide
used in Tubes 1, 2, and 3.
10. Using the scalpel, cut 2 cubes of fresh potato, each the size of the liver used.
Place 1 potato cube in Tube 9.
11. Grind the other potato cube in the mortar with sand. Place the potato-sand
mixture in Tube 10.
Place in a test tube graphic
TAKS Objective 2
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Biology
Data Table:
Reactions of Organic and Inorganic enzymes and Hydrogen Peroxide
TEST TUBE #
Reactants
Reactions
1
MnO2 + H2O
2
MnO2 + H20
3
MnO2 + H2O2
4
TT #1 Boiled + H2O2
5
Liver + H2O2
6
Ground Liver + H2O2
7
Boiled Liver + H2O2
8
Sand + H2O2
9
Potato + H2O2
10
Ground Potato + H2O2
Discussion:
1. What was the purpose of Tube 2?
2. Do you have any evidence that manganese dioxide catalyzes the breakdown of
hydrogen peroxide instead of reacting with it?
3. What additional steps in the procedure would be needed to confirm this?
TAKS Objective 2
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Biology
Biochemists have obtained experimental evidence that manganese dioxide is
indeed a catalyst in this reaction. Consider the formula of hydrogen peroxide
and the kind of reaction you observed in Tube 3.
4. What are the most likely products of the breakdown of hydrogen peroxide?
5. How might you confirm your answer?
6. What caused the reaction when you put the liver into Tubes 5 and 6?
7. How do you explain the difference in activity resulting from the whole piece
of liver and from the ground liver?
8. Why is Tube 8 necessary for this explanation?
9. How do you explain the difference in activity resulting from fresh and boiled
liver?
Suppose that someone compared Tubes 3 and 5 and concluded that liver
contains manganese dioxide.
10. What evidence do you have either for or against this conclusion? (Consider
the reaction in Tube 4.)
11. What additional information do the results from Tube 9 and 10 provide?
TAKS Objective 2
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Biology
A Simple Enzyme Model
Sandra Gonzales (John Jay High School), Barbara Larger (O’Connor High School), and Debbie
Richards (Bryan High School)
Introduction:
Biology teachers know the value of inexpensive models to demonstrate abstract
biological concepts. Today’s biology students are highly visual and tactile
learners. Hands on models and manipulatives allow the learner to engage multiple
senses during the learning cycle and are therefore useful teaching tools. The
model described here can be prepared in about 30 minutes using inexpensive, yet
colorful, craft foam.
Teaching Objective:
The learner will be able to identify the components of a typical catalytic cycle and
describe the relationship among the enzyme, substrate, and active site.
Materials Needed: (for a class of 28 students)
28 pieces of 5x7 craft foam
1 piece of 8x11 craft foam
2 3cm strips of self-stick magnetic tape
1 roll of masking tape
1 pair of scissors
1 gallon sized resealable storage bag
TAKS Objective 2
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Biology
Preparation Instructions:
Obtain two different colored 5 x 7 pieces of craft foam. Place both piece on top of
each other lining up the edges. Cut out a random shape along one side of the craft
foam pieces. This cut will produce the substrate and active site shape for two
model sets. See Fig. 1 below.
Fig. 1
As you are preparing the model sets, be sure to use random shapes for the active
sites. See Fig. 2 below. This will allow you to clearly demonstrate enzyme
specificity as you explain the catalytic cycle.
Fig. 2 Examples of
random shapes
Remove the small piece from each color of foam and cut it in half. Tape one of
the ½ pieces to the other colored ½ piece producing a new, two-colored piece that
will represent the substrate. Repeat with the two remaining halves.
TAKS Objective 2
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Biology
Fig. 2
Use the 8x11 sheet of craft foam to prepare an oversized model to use as a teacher
demonstration model. Write the labels enzyme and substrate on your teacher
model. Attach the self-stick magnetic tape to the back of your model so that you
can place the model on your white board.
Suggestions for using the model during an introductory lesson on enzymes:
1. Distribute an enzyme model and a non-matching substrate model to each
student upon arrival. Make sure that you do not give a matching enzyme
and substrate to the same student.
2. Instruct the students to stand up and move around the room to locate the
classmate that is holding the craft foam piece that fits with their large
piece. Although the students are not aware of the terminology at this
point, what you are really asking them to do is to match their enzyme with
its substrate. Once they find their mate, the one holding the larger piece
should keep both pieces. (This way at the end of the matching episode,
each student has a complete enzyme/substrate set.)
3. When they have located a mate, the partnership should come up with three
observations about the pieces. Instruct them to list their observations on
the board or be ready to share their observations aloud.
4. As students return to their seats, have them state their observations aloud.
Encourage those who have made detailed observations.
5. Explain the role and action of enzymes in biological systems using your
large teacher demonstration model.
6. Have students use their models to demonstrate their understanding of the
vocabulary terms. For example, ask the students to hold up the part of
their model that represents the enzyme. Practice identifying the
components until you are confident that students understand the terms.
7. Revisit the model using specific enzyme, substrate and product names. For
instance, using catalase’s cycle as an example, show the students which
model components would represent the catalase, hydrogen peroxide,
oxygen and water.
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8. Write the terms sucrose, glucose, fructose, and sucrase on the board and
ask the students to discuss with their partner which model piece represents
each term.
9. In closure, have the students use small labels and use them to identify the
components of their model. Alternately, students could use post it notes to
label their model pieces by placing the labels directly on the surface of the
model. In addition to labeling the components, the students could write a
paragraph describing enzymes and the catalytic cycle three things they
know about enzymes.
Closure Labels:
Enzyme
Substrate
Product
Product
Lactase
Lactose
Glucose
Galactose
This lesson idea is the result of collaborative efforts of Sandra Gonzales (John Jay High School),
Barbara Larger (O’Connor High School), and Debbie Richards (Bryan High School) during
James Madison Technology Summer Institute.
TAKS Objective 2
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Biology
Enzyme Model
Partner Performance
Use the enzyme model as you work in pairs to demonstrate your
understanding of the following:
Part I. Show your partner the model component that represents:
_____Enzyme
_____Substrate
_____Product
_____Enzyme/Substrate complex
_____Competitive inhibition
_____Non-competitive inhibition
Part II. Label the diagram below to show the breakdown of
sucrose by sucrase.
Word Bank
Sucrase
Sucrose
Sucrase/Sucrose Complex
Glucose
Fructose
Sucrose
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Biology
Name:
Biology Enzyme Quiz
1. Label the enzyme diagram below using the following general terms:
product, substrate complex, enzyme, substrate
2. Label the diagram above using these specific terms: catalase,
catalase/hydrogen peroxide complex, water and oxygen, hydrogen
peroxide
Circle the correct choice:
3. Enzymes (raise/lower) the activation energy of a reaction.
4. Enzymes are (proteins/carbohydrates).
5. Enzymes are (used up/not used up) in the reactions they catalyze.
6. Circle all of the enzymes in the list below:
Sucrose,maltase, amylose, maltose, lactase, amylase, lactose, sucrase,
TAKS Objective 2
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Biology