Name
Date
Group
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TOOTHPICKASE LAB: An Introduction to Enzymes and Rate of Reactions
BACKGROUND INFORMATION
Chemical reactions make life possible. In each individual cell of a human there are many
chemical reactions taking place. These chemical reactions involve the breaking and reforming
of chemical bonds between molecules which are transformed into different molecules. For
example, after you eat food, your body will break down the food to glucose. To get energy
out of the glucose molecule, a series of reactions must take place. Without enzymes theses
reactions would not occur quickly enough and ordinary activities of life would come to a stop.
Enzymes help your body carry out those chemical reactions quickly enough to keep you alive!
1. What do chemical reactions involve?_________ ____________________________________________
2. When you eat, your body breaks down your food to produce the sugar __________________________.
3. Why are enzymes important?___________________________________________________________
Enzymes are special types of proteins that catalyze biochemical reactions. Enzymes increase the rate of reactions but are
not used up in the process because they are reused over and over. Enzymes are referred to as “biological catalysts” since
they help to increase the rate of chemical reactions in living things. Enzymes work by helping to lower the activation energy
of a reaction, which allows the reaction to speed up.
4. Define ENZYME:_______________________________________________________________
5. T or F: Enzymes increase the rate of a reaction.______
6. T or F: Enzymes are not used up because they are reused over and over.____
7. Why are enzymes called Biological Catalysts?_ ______________________________________
8. Enzymes help __________________ the activation energy of a reaction, which allows the reaction to speed up.
Enzymes are specific for each reaction and are reusable. Enzymes have an area called the active site. The active site is where
a specific substrate will bond temporarily while the reaction is taking place. In this activity, you will simulate the reaction of
an enzyme with its substrate. Your hands will represent the enzyme, “Toothpickase,” and your thumb and index fingers are
the active site. The toothpicks are the substrates.
9. Enzymes are ________________for each reaction and are reusable.
10. Define ACTIVE SITE:_______________________________________________________________
11. What will your hands represent?_________________ What is the name of this enzyme?______________
12. What will your thumb and index finger represent?___________________________
13. What do the toothpick represent?________________________________
PURPOSE: To determine the effects of temperature change (room temp. vs. ice bath) on enzyme activity.
HYPOTHESIS:
MATERIALS:
____120 toothpicks per team
____Pencil
____clock/watch with a second hand
PROCEDURE:
Here are the rules of the lab: After you form one neat pile of toothpicks, you are to break as many SINGLE toothpicks you
can using only your thumb and index fingers in a given period of time. Once a toothpick (substrate) is broken, the broken
toothpick must be thrown back into the original pile. Do not break toothpicks already broken!!
STEP 1: Count out 60 toothpicks. Stack them into one neat pile.
STEP 2: Break as many toothpicks as you can in a 10 seconds and record in Table 1. Remember, always throw broken
toothpicks back in the pile, but don’t re-break them!
STEP 3: Do another 20 seconds of breaking and counting. Record the number of toothpicks broken.
STEP 4: Continue breaking toothpick for these time intervals: 30, 60, 120, 180, 360 seconds.
**You may run out of toothpicks and will not be able to finish the longer time intervals.**
STEP 5: Repeat the procedure above, but this time you must lower the temperature of the reaction by soaking the
“Toothpickase” enzyme in ice water for 20 seconds before each trial. Record the data for this step in Data Table 2.
DATA TABLE 1: REACTION AT ROOM TEMPERATURE
Time
Number of
Reaction Rate
seconds Toothpicks Broken
(# broken/seconds)
DATA TABLE 2: COLD TEMPERATURE REACTION
Time
Number of
Reaction Rate
seconds
Toothpicks Broken
(# broken/seconds)
10
10
20
20
30
30
60
60
120
120
180
180
360
360
Graph the Results for Room Temperature and Cold Temperature Reaction Below: Label the X Axis with
Time (sec) and the Y axis with Reaction Rate (# broken/sec). Be sure to give your graph an appropriate title.
LAB ANALYSIS QUESTIONS
***BE SURE TO ANSWER ALL QUESTIONS IN COMPLETE SENTENCES***
1. What are the controls in this lab?
2. What is the dependent variable?
3. What is the independent variable?
4. Write a description of the results from each of the data tables above.
Note any trends or patterns over time.
DATA TABLE 1:_______________________________________________________________________________
DATA TABLE 2:
5. What happens to the reaction rate as the supply of toothpicks runs out?____________________________
6. What would happen to the reaction rate if the toothpicks were not in a neat pile, but instead, spread out over the
lab station?____________________________________________________________________________
7. What would happen to the reaction rate if 300 toothpicks (substrate) were used instead?________________
8. What would happen to the reaction rate if there were 4 toothpickases available (in other words, what if there were
2 people breaking toothpicks instead of one person)?____________________________________
9. What would happen to the reaction rate if you wore bulky gloves over your hands (toothpickase)?_______
10. What do you think would happen to the reaction rate if your thumbs (active site) were taped to your
hands?__________
. WHY?_____________________________________________________________
Conclusion:
Write a paragraph with each of the following parts. (Check off each of the following parts as you finish them.
The paragraph should make sense on its own without reading the directions.
Be sure to include the following:
Restate the purpose,
Restate your hypothesis,
Explain
if your hypothesis was correct or not,
give evidence to support this,
List/Explain any
sources of error (minimum 2),
Explain what you would change to improve your results if you
were to do this experiment again