Toothpickase Activity
Background information
Enzymes are agents that change the rate of a reaction without being changed themselves. In this activity, your
hand becomes the functional part of an enzyme that we will call toothpickase. You will be called toothpickase
since you will be breaking toothpicks and every enzyme ends in –“ase.” Your substrate is the toothpick. When you
find a toothpick, you react with it and break it into two pieces. Your goal is to break toothpicks quickly and
efficiently (without damaging the toothpickase in the process).
Procedures
Part 1
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Groups of 3 people
a. 1 person will be breaking toothpicks.
b. Another person will be keeping track of how many toothpicks are broken.
c. Last person will be keeping time and recording data.
Select approximately 250 toothpicks and divide them into 6 equal piles.
You will be breaking toothpicks by holding the toothpick between your fingers and thumb of one hand.
There will be NO breaks in timing.
Since you will be breaking toothpicks, make sure that the toothpick piles are conveniently located as
speed is the main measurement.
RULES
a. You can only BREAK ONE (1) toothpick at a time
b. You must BREAK the toothpick CLEANLY – if there is any attachment, it does not count.
RECORD the total number of toothpicks broken at 0 sec. 10 sec. 30 sec. 60sec. 120 sec. 180 sec.
Part 2
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Same RULES as in Part 1.
Select approximately 250 toothpicks and divide them into 6 equal sized piles.
Tape a popsicle stick to the middle finger of the student breaking toothpicks. (They should not be able to
bend their finger.)
RECORD the total number of toothpicks broken at the same time intervals as in the previous part.
Part 3
1. Same RULES as in Part 1 and 2.
2. Select approximately 150 toothpicks and divide them into 6 equal sized piles.
3. Select approximately 100 round toothpicks and divide them into the existing 6 piles.
4. NOW: There are 2 types of toothpicks in each pile: round and flat toothpicks. If the breaker selects a
ROUND toothpick, they must try to break it but eventually fail. The ROUND toothpicks must NOT be broken.
They will be placed in a separate pile at the end of the table.
5. RECORD the total number of toothpicks broken at the same time intervals as in the previous parts – DO NOT
RECORD THE NUMBER OF ROUND TOOTHPICKS.
Data Collection Tables
Toothpick Metabolism Data
Time (seconds)
Toothpicks metabolized
PART 1
Toothpicks metabolized
PART 2
Toothpicks metabolized
PART 3
0
10
30
60
120
180
Reaction Rates
For each of the following time intervals, calculate the rate of reaction of the toothpickase enzyme using
the following formula for the slope of the line graphed above. Note: Guidelines for graphing are on the next page.
Reaction Rate Calculation = M2 – M1
T2 – T1
M = number of toothpicks metabolized by a given point in time
T = time
Reaction Rate Data
Time Period (seconds)
0 – 10
10 – 30
30 – 60
60 – 120
120 – 180
Rate of Reaction
PART 1
Rate of Reaction
PART 2
Rate of Reaction
PART 3
GRAPHING
1. Graph the Toothpick Metabolism data in PART 1.
2. Graph the Toothpick Metabolism data in PART 2.
3. Graph the Toothpick Metabolism data in PART 3.
NOTE:
 You should plot the three sets of data on one graph.
 Don’t forget to label the axes, provide a title and a key.
 You will use Microsoft Excel or Google docs to graph your data. Please show the data
tables next to your graphs.
ASSESSMENT QUESTIONS – Please type your answers in complete sentences.
1. In the toothpickase activity, identify the following:
a. Substrate
b. Enzyme
c. Active site
d. Product
2. What would happen to reaction rate if more toothpicks (substrate) were added?
Indicate what would happen initially and then what would happen over an extended
period of time.
3. What would happen to reaction rate if there were two “breakers” (more enzymes)?
4. Explain what would happen to an enzyme facilitated reaction if temperature were
increased. Be sure to include the effect if temperature were increased to 100 ⁰C.
5. What is the optimal temperature (⁰C) for enzymes functioning in the human body?
6. Explain how the Toothpickase activity modeled competitive inhibition. Be specific.
7. Explain how the Toothpickase activity modeled allosteric (noncompetitive) inhibition?
Be specific.
Assessment Questions
1. In the toothpickase activity, identify the following:
a. Substrate:
c. Active Site:
b. Enzyme:
d. Product:
2. In part 1 what would happen to the reaction rate if more toothpicks (substrates) were added? Why?
3. In part 1 what would happen to the reaction rate if there were two “breakers” (more enzymes)?
4. If you hold a tennis ball in the palm of your hand and try to break toothpicks, are you able to do so?
Why or why not?
5. In terms of enzyme action the tennis ball would represent a __________ because it is preventing the
action of the enzyme. The palm of your hand would represent the __________ the place where the
_______ binds to the enzyme.
6. Explain how the Toothpickase activity modeled allosteric (non-competitive) inhibition?
7. Explain how the Toothpickase activity modeled competitive inhibition?