Honors Biology Enzymes and Enzymes Lab Study Guide
Definitions:
Enzyme: Regulators of chemical reactions
Activation Energy: The amount of energy that reactants must absorb before a chemical reaction
begins
Substrate: Specific reactant an enzyme acts on
Active Site: Pocket or groove where substrate fits on an enzyme
Induced Fit: Slight change in active shite’s shape to better fit the substrate
Inhibitor: Reduces enzyme productivity
Denature: Changes enzyme so is less effective
Catalase Lab Procedure:
1) Part 1: Enzyme Concentration
a. With catalase concentration A, soak disc for 10 seconds
b. Place disc in hydrogen peroxide and time trip from bottom to top
c. Repeat a and b twice more and find average
d. Repeat steps a, b, and c using concentrations B and C
2) Part 2: pH
a. Soak disc in catalase for 10 seconds
b. Place in pH 3 hydrogen peroxide mixture and time trip from bottom to top
c. Repeat a and b twice more and find average
d. Repeat steps a, b, and c using hydrogen peroxide mixtures with pH 7 and pH 11
3) Part 3: Temperature
a. Soak disc in catalase for 10 seconds
b. Place in 32oF hydrogen peroxide and time trip from bottom to top
c. Repeat a and b twice more and find average
d. Repeat steps a, b, and c using hydrogen peroxide at 98.6oF and 105oF
Lab Graph Conclusions:
Enzyme Concentration
40
35
30
25
20
15
10
5
0
Enzyme Concentration
pH
12
10
8
6
4
2
0
1
4
7.4
10
14
pH
Temperature
12
10
8
6
4
2
0
0
25
50
75
Temperature
98.6
105
Enzyme Inhibition:
There are two main types of inhibitors, competitive and noncompetitive. Competitive inhibitors
stop enzymes from acting by binding to the active site in competition with the substrate. This is
akin to a car competing with a shopping cart for a parking space in a parking lot. The second
type is a noncompetitive inhibitor. This binds to another part of the enzyme and slightly
changes the shape of the active site so the substrate won’t fit. This is like when people do a
really bad parking job, so you can’t park in a parking space, even though they aren’t competing
for your space.