Introduction
In biological scenes, enzymes are of import in order to excite reactions that usually would n’t go on as rapidly by catalysing reactions so that they require less activation energy than without the enzyme nowadays. In an enzyme-catalyzed reaction, the substrate binds to the active site of the enzyme, doing a impermanent bead in the energy required to trip the reaction of the molecule so that the merchandise of the reaction is formed.2 After the enzyme has completed it ‘s undertaking, it is so recycled to be used once more in another reaction. However, enzymes are specific to peculiar reactions, because of its structure.2 In beings, catalase stimulates the reaction where H peroxide is decomposed into H2O and oxygen.1 This procedure is measured by the equation 2 H2O2 2 H2O+O2 ( gas ) .3 This enzyme is found specifically in mammalian tissues to forestall a build-up of the peroxide in tissues, hence doing damage.1 In this experiment, H peroxide was placed into beakers with sulphuric acid and so titrated to make a basal line for the experiment. After this was established, the catalase will be placed into the mixture at for different times, and so titrated. Therefore, the mixture with the catalase in it for the most sum of clip should demo a alteration in colour faster when titrated than that of the base line or mixtures that held the catalase in them for shorter sums of clip.
Materials and Methods
100 milliliter of 1.5 % H2O2
Distilled Water
55 milliliter of KMnO4
70 milliliter H2SO4
7 milliliter of Catalase
Pipets labeled H2O2, KMnO4, H2SO4 and Titrate
12 beakers
Stop Watch
Labels for the cups
Establishing a Base Line
Topographic point 10 milliliter of the 1.5 % H2O2 solution into a clean cup
Add 1mL of H2O to the cup, this will subsequently be replaced by the catalase
With utmost attention, add 10mL of H2SO4 to the cup
Mix the solution good
Remove a 5mL sample of the solution and topographic point into another cup to be titrated
Using a 5mL pipette, add the KMnO4 one bead at a clip, until a pink or brown colour is achieved and sustained.
Record readings
Uncatalyzed Rate of H2O2 Decomposition2
Topographic point 15mL of 1.5 % H2O2 into a beaker
Store the solution, exposed, for 24 hours at room temperature
Repeat stairss 2-5 from the “ Establishing a Base Line ” to reason the sum of H2O2 staying in the beaker.
Record findings
Enzyme-Catalyzed H2O2 Decomposition
Label 7 beakers with 10, 30, 60, 90, 180, and 360. This will be the sum of seconds the catalase will be in the H2O2 solution.
Add 10mL of the solution into each of the beakers
Add 1mL of the catalase and utilize the halt ticker to clip the reaction
Gently whirl for the sum of clip listed ( ex. If 10s, whirl for 10s etc. )
At the right clip, add 10 milliliter of H2SO4
Once this has been completed for each of the times, titrate with the KMnO4, adding merely one bead at a clip, so entering the findings.
Consequences
Table 1 Base Line Calculation
Concluding reading of Pipette
8.5mL
Initial Reading of Pipette
5mL
Base Line ( Final-Initial )
3.5 milliliter KMnO4
Table 2 Uncatalyzed Rate of H2O2 Decomposition2
Concluding Reading of Pipette
4mL
Initial Reading of Pipette
10mL
Sum of Titrate
6mL
Sum of H2O2spontaneously decomposed
2.5 milliliter
Percentage of H2O2spontaneously decomposed
22 %
Table 3 Enzyme-Catalyzed Chemical reaction
KMnO4 ( milliliter )
10
30
60
90
120
180
360
Base Line
3.5
3.5
3.5
3.5
3.5
3.5
3.5
Final Reading
8.2
8
7.4
7.4
7
6.8
6.4
Initial Reading
5
5
5
5
5
5
5
Sum of KMnO4Consumed
3.2
3
2.4
2.4
2
1.8
1.4
Sum of H2O2Used
.3
.5
1.1
1.1
1.5
1.7
2.1
Discussion
Once the experiment was conducted, the consequences were as followed, the sum of H2O2 in the beakers decreased as the sum of clip the catalase was in the solution increased. This information proves the hypothesis to be true, and is represented by Table 3, and is validated by the constitution of a basal line in Table 1 and Table 2. Tables 2 shows that without the presence of catalase, the H2O2 decomposes easy, as the sum of H2O2 did n’t alter dramatically after 24 hours as compared to the base line established on the twenty-four hours of the experiment. However, when the catalase was added, the sum of H2O2 decreased much faster than without the added catalase.
Table 1 Base Line Calculation
Concluding reading of Pipette
8.5mL
Initial Reading of Pipette
5mL
Base Line ( Final-Initial )
3.5 milliliter KMnO4
Table 2 Uncatalyzed Rate of H2O2 Decomposition2
Concluding Reading of Pipette
4mL
Initial Reading of Pipette
10mL
Sum of Titrate
6mL
Sum of H2O2spontaneously decomposed
2.5 milliliter
Percentage of H2O2spontaneously decomposed
22 %
Table 3 Enzyme-Catalyzed Chemical reaction
KMnO4 ( milliliter )
10
30
60
90
120
180
360
Base Line
3.5
3.5
3.5
3.5
3.5
3.5
3.5
Final Reading
8.2
8
7.4
7.4
7
6.8
6.4
Initial Reading
5
5
5
5
5
5
5
Sum of KMnO4Consumed
3.2
3
2.4
2.4
2
1.8
1.4
Sum of H2O2Used
.3
.5
1.1
1.1
1.5
1.7
2.1
Citations
1. Britannica, Encyclopedia. “ Catalase ” . Encyclopedia Britannica, 9 Nov. 2009. Web. 9 Nov. 2009. hypertext transfer protocol: //www.britannica.com/EBchecked/topic/99062/catalase
2. College, Board. AP Biology Lab Manual. New York: College Board, 2001. Print.
3. Pack, Phillip E. Cliffs AP AP Biology 3rd Edition. 111 River Street, Hoboken, NJ: Wiley Publishing Inc. , 2007. Print.
