MODULE TOPIC:
Manipulating variables to determine optimal function
NAME OF LESSON PLAN:
Enzyme Function
STANDARD(S) & INDICATOR(S):
NGSS
MS-LS1-2. Develop and use a model to describe the unction of a cell as a whole and
ways parts of cells contribute to the function.
CCSS-Mathematics
HSF-IF.B.4. For a function that models a relationship between two quantities, interpret key
features of graphs and tables in terms of the quantities, and sketch graphs showing key features
given a verbal description of the relationship.
LEARNING OBJECTIVE(S): Students will be able to:
Given a set of key variables, design and conduct an experiment that illustrates the optimal
environment for catalase function.
MATERIALS:
Part 1
Lesson/Note Templates
Enzyme /substrate concentration activity (“Toothpick-ase lab”)
Toothpicks
Part 2
Beakers
Thermometers
Catalase source (liver)
pH solutions (2,4,6,8,10,14)
Hydrogen peroxide
Hot plates
Water
Ice
Part 3
Graph paper
Data Analysis templates
Conclusion templates
LIST OF HANDOUTS
Toothpickase lab
“Design an experiment” Template
Scoring Rubric
BACKGROUND INFORMATION:
This lesson is used to place emphasis on using experimental design in order to determine
the outcome of combined variables. Using the concept of enzymes as a mechanism,
students will gain experience in designing data collection and analysis methods in order
to measure specific outcomes. Students have engaged in less extensive versions of this
throughout the year, and are expected to operate completely independently during the
design, conduct, and analyze phases of this lesson. Being that it is centered on
investigation and manipulation of multiple variables on the rate of reaction this lesson
mirrors the major takeaway from my experience in the RET program. Prior to this lesson,
students were also given a demonstration of the work done during the RET program in
which emphasis was placed on experimental design, data collection, and data
organization.
CLASSROOM ACTIVITY DESCRIPTION
(LABORATORY/EXERCISES/PROBLEMS) including detailed procedures:
Part 1:
Lesson begins with introductory information regarding enzymes. This segment of the
course directly follows the unit on molecular transport in which enzymes were mentioned
indirectly. Key concepts in the introductory phase will incorporate enzyme/substrate
interaction, biological function, environmental requirements, and enzyme/substrate
concentration.
Students will then engage in the “Toothpickase” activity. During this activity, students
blindly break toothpicks in one minute intervals. The number of toothpicks per interval
increases exponentially, and students find that, while they can initially break all of the
toothpicks, the number of broken picks becomes stagnant at higher concentrations. The
activity is done in aim of illustrating the point that the enzyme (their hands) has a
productivity ceiling in relation to the enzyme/substrate concentration within the
environment.
Part 2:
Students read pre-lab information regarding the enzyme catalase.
Students are given a set of parameters in which to answer the following question:
“Which conditions will lead to the highest reaction rate in catalase”
The teachers demonstrate that rate is measured in the amount of time it takes for a
catalase soaked disc of filter paper to float when placed in hydrogen peroxide.
Students are then given a list/demo of materials and are provided with the directive
“Design an experiment that will help you answer your question. It is emphasized that,
while each group of two will collect data regarding one set of conditions, the class will be
working as a whole to determine the efficacy of the conditions as a whole.
Students are expected to have developed enough skill in experimental design at
this point to incorporate standard techniques such as: Manipulating temperature through
water baths, altering concentration, measuring/adjusting pH, and general data recording
practices.
The experimental/data collection segment of this phase is completely self-developed by
the students, however, the teachers make it clear that they are completely available and
willing to assist with guidance.
Part 3:
Students organize, graph, and compare data collected during part 2. Using the class data
as a whole, students will communicate and come to a consensus regarding the combined
optimal environmental factors for catalase to function in. At the conclusion of this phase,
students will provide us with their self-made procedures, data records, and the
conclusions gained during their individual experiments. The conclusion/evidence base for
the unified functioning range will be communicated verbally by the class as a whole.
SAMPLE QUESTIONS TO ELICIT CLASS DISCUSSION:
Why does the body stop working if specific (temperature, pH, hydration, etc…) is not
maintained?
Why is it true to say that knowledge can rarely exist in the absence of experimentation?
How does an imbalance in pH impact enzyme reaction rate?
How does increase in temperature impact enzyme reaction rate?
How does temperature decrease impact enzyme reaction rate AND why is this impact
different from the two described above?
Would digestion be able to take place without enzymes present?
HOMEWORK ACTIVITY/EXERCISES/PROBLEMS:
Students are not expected to finish the question portions associated with part 1, part 2, or
part 3 of this lesson in class. These questions will be assigned as homework or tutoring
session assignments.
PARAMETERS TO EVALUATE STUDENT WORK PRODUCTS:
Assessment of the design of the experiment illustrating the optimal environment for
catalase function. (See rubric)
ACKNOWLEDGEMENT
This material is based upon work supported by the National Science Foundation under
Grant No. 1301071
Copyright © 2016 by the Center for Pre-College Programs, of the New Jersey Institute of
Technology. All Rights Reserved.
Supporting Program: Center for Pre-College Programs, at the New Jersey Institute of
Technology
Contributors
Owen Ambrose, Montclair High School, Montclair, NJ, Primary Author
Howard Kimmel, Levelle Burr-Alexander - Center for pre-College Programs, NJIT.
Md Mahbubur Rahman, Dr. Ecevit Bilgili, Dr. Rajesh Dave - C-SOPS, NJIT
Catalase Lab Scoring Rubric
Group Members
names:________________________________________
Score Earned:_____________________________
Area
0
Point
Not
done
1 Point
3 Points
5 Points
7 Points
10 Points
Does not
address
question or
variables
Inaccurately
reflects
question but
shows clear
thought
Accurately
reflects
question but
misses some
variables
Experiment
Not
done
Did not
follow
procedure
Shows
lack of
effort in
aligning
question
with
procedure
Followed
procedure
poorly
Followed
procedure
with errors
Data
Not
done
incomplete
Mostly
complete
Organization
Not
done
Most
elements
missing
Some
elements
missing
Conclusion
Not
done
Fully
inaccurate
Mostly
inaccurate
Complete
with
mistakes
Elements
present but
with many
mistakes
Partially
accurate
Followed
procedure but
lacked
understanding
of why
Complete with
few mistakes
Accurately
reflects
question
and
considers
all
variables
Accurately
followed
procedure
with
purpose
Perfect
Procedure
Elements
Elements
present bit with present
few mistakes
with no
mistakes
Mostly
Fully
Accurate
accurate
Name _______________________________________ Date ______________
Introduction to Catalase
Go to:
http://pdb101-test.rcsb.org/teach/tests/enzymes-pre-test
Take the pre test use class code DCPT0022
Next read the following and answer these questions.
http://pdb101.rcsb.org/motm/57
1. Why is oxygen dangerous?
2. What are riboflavin and niacin?
3. Why is hydrogen peroxide dangerous?
4. Why is it bad if DNA mutates?
5. What two enzymes fight against oxygen damage?
6. How fast does Catalase work?
7. Why is it important that catalase be unusually stable?
8. Explain the 2 steps that catalase does to break up H2O2 (hydrogen peroxide).
The Toothpickase Activity
Introduction:
Organisms on every level, from elephants and blue whales down to amoebas and lowly
bacteria, can be described as being simply bags of chemical reactions. If left to their own,
most of these reactions would either not happen at all or cause the organism to basically
explode. Just as matches won’t light on their own, these reactions need to be helped along
so that they can be controlled.
Biologists are very interested in enzymes – protein catalysts that control many of the
reactions that occur in living organisms. Enzymes are used in all metabolic reactions (and
that’s a LOT of reactions) to control the rate of reactions (so you don’t burn up) and
decrease the amount of activation energy necessary for the reaction to take place.
Enzymes are specific for each reaction and are reusable. Enzymes have an area called the
active site to which a specific substrate will bond temporarily while the reaction is taking
place.
We know that conditions that change the shape of the active site (denaturation) such as
heat and pH dramatically change the speed at which the enzyme can work. In this
activity, you will actually become an enzyme of sorts (you’re not actually a protein) and
cause a reaction to take place. Toothpicks can’t break on their own! More specifically, we
will model as a class how changes in substrate concentration (number of toothpicks
available) affect reaction rate (number of toothpicks broken per second).
Procedure:
In this activity, the toothpicks are the substrate and you are now the enzyme
toothpickase. When you break a toothpick, the place where the toothpick fits between
your fingers is the active site of the enzyme.
1. Each team of two will split the jobs. One student will be the enzyme and you
break toothpicks one at a time as fast as you can. The other student will keep
count of how many toothpicks get broken.
2. For each trial, each team will count out a pile of toothpicks and then be given 10
seconds to break as many toothpicks from that pile as possible. The person
breaking the substrate CANNOT look at the toothpicks.
3. In reality, the products of the reaction do not necessarily go away so we need to
model this. BE SURE TO PUT BROKEN TOOTHPICK BACK INTO YOUR
PILE AS YOU BREAK THEM
4. Record the data in the table.
Name ________________________________ Date _____________________
Data Table:
Starting toothpick count Number of toothpicks broken Enzyme rate (t-pix/sec)
1
5
10
20
30
40
Graph your data:
Analysis & Conclusions:
1. What do you think your team’s reaction rate would be if given a pile of 1000
toothpicks? 10,000? Explain why.
2. At what substrate concentration (starting toothpick count) did your team’s
reaction rate stop increasing?
3. Why is this [the answer to previous question] called the “saturation point”?
4. What happens if the enzymes wore bulky gloves when picking up toothpicks?
Explain
5. What does wearing the gloves represent?
6. What would happen to the rate of reaction if the enzymes (your fingers) were
soaked in ice water for five minutes before breaking the toothpicks? And as the
enzymes warmed up again would the rate eventually return to normal?
7. What if the enzymes (your fingers) were put into boiling water for five minutes
(denatured)? Would the reaction rate return to normal after the active site cooled
down? Why is this a different result than putting the enzyme in ice water?
8. Which causes a more permanent change in the enzyme, cooling or heating?
Conclusion Template Sheet
When Writing your conclusion consider the following:
How was your question addressed?
What form of data was collected?
What did the data show?
What answer did you arrive at?
How does the data work as evidence for that answer?
What questions remain even after the experiment?
What would you do differently?