Name:
Date:
Period:
Toothpickase Activity
INTRODUCTION
This is a “hands-on” lesson in enzyme action, demonstrating the natural increase in reaction
rate, the leveling off of the reaction and the subsequent drop in products produced as the substrate
is used up. You are to pretend that toothpicks are the substrate to be broken down and your hands
are an enzyme, complete with an “active site” (between your fingers and thumb.) Notice that the
enzyme (your hand) is much larger than the substrate (toothpicks.) As you will be performing the
activity with your eyes closed, this simulates the random contact made between substrate and
enzyme. The object of the activity is to break as many toothpicks in half as possible in two
minutes to test the “enzyme”.
During the activity, you will also notice that the substrate will not break unless you find just the right
spot (the bonding site) and that you will naturally find a maximum rate of reaction, the top speed at
which your hands can find and break an enzyme. This speed may lower during the activity as your
hands become tired, the pieces are all too small to break and the substrates get more and more
scattered in the “solution” (your playing field.) Throughout the activity, notice that the enzyme
(your hands) remains unchanged throughout the reaction.
Consider that your hands are like an enzyme called toothpickase. Your
hands (the enzyme) can split toothpicks (your substrate) in half.
Part 1: How fast toothpickase works
Directions: Break as many toothpicks as you can without looking. Record
how many toothpicks are broken in 10 second intervals.
Time (seconds)
0
10
20
30
40
50
60
70
80
90
Number of toothpicks broken
Name:
Date:
Period:
1. How does the number of toothpicks broken change over time?
Part 2: Adding another substrate into the mix
Directions: Mix some macaroni in with your toothpicks. Break as many
toothpicks as you can without looking. Record how many toothpicks are
broken in 10 second intervals.
Time (seconds)
0
10
20
30
40
50
60
70
80
90
Number of toothpicks broken
1. How does mixing in a “wrong” substrate affect how many
toothpicks are broken by toothpickase?
Name:
Date:
Period:
Part 3: How temperature affects how fast toothpickase works
Directions: Time how long it takes you to break 10 toothpicks without
looking. Then, hold your hands under running water for a few minutes.
Try breaking the 10 toothpicks again while timing yourself.
Temperature
Time to break 10
toothpicks (seconds)
Room temperature
toothpickase
Cold toothpickase
1. How does temperature affect the time in which toothpicks are broken
by toothpickase?
Conclusions
1. What is an enzyme? What is the enzyme is this activity?
2. What is a substrate? What is the substrate in this activity?
3. Write a sentence to describe how mixing in another substrate
affects how fast an enzyme works.
4. Write a sentence to describe how temperature affects how fast
an enzyme works.
Name:
Date:
Period:
Part 1: How fast toothpickase works
Time (seconds)
0
10
20
30
40
50
60
70
80
90
Number of toothpicks broken
Part 2: Adding another substrate into the mix
Time (seconds)
0
10
20
30
40
50
60
70
80
90
Number of toothpicks broken
How does adding in a second substrate affect the enzyme? Use the graph to
support your answer.
Name:
Date:
Period:
Graph your data from Part 1 and connect the dots to make a line. Then, graph your
data from Part 2 and connect the dots to make a line. Use different colors for each
line and make a key to the graph. Finally, answer the question.
Number of toothpicks broken
Toothpickase Efficiency
Time (seconds)
KEY
Name:
Date:
Period:
DISCUSSION (answer on a separate sheet of paper)
1.
Predict what would happen if we used 100 toothpicks/student?
2.
Predict what would happen if the toothpicks were more spread out on bigger table?
3.
Predict what would happen if two pairs of hands acted as enzymes at table?
4.
Predict what would happen if your hands were very cold?
5.
Predict what would happen if the teacher had added some plastic toothpicks to your
desk?
6.
Predict what would happen your thumbs had been taped to your "pointee” (index) finger?