Name: Simon Sohn Enzyme Experiment

Name: Simon Sohn Group members: Misaki, Hiroki Date of experiment: Dec. 6th 2010

Factors affecting the speed of a catalase reaction <Concentration of the substrate>

Aim: To see if the concentration of the hydrogen peroxide can affect the speed of the catalase reaction Hypothesis: The higher concentration of the hydrogen peroxide, the faster the speed of the catalase reaction. Thus, more oxygen will be produced during the reaction. This will happen because more substrates will be there in higher concentration of hydrogen peroxide, which are to be broken down by the enzyme in liver. Variables: Input variable: The concentration of the hydrogen peroxide. I will change it by using 0.5%, 1% and 1.5% hydrogen peroxide in the experiment. Output variable: The amount of oxygen produced in the catalase reaction. I will measure the total amount of the solution (H202+liver+foam). Control variables:

Control variable 1: The amount of liver. I will keep it the same by using the exact same amount of liver by measuring its weight.

Control variable 2: The temperature of the hydrogen peroxide. I will keep it the same by keeping the same temperature in the place where the experiment is conducted.

Control variable 3: The type of liver. I will keep it the same by using the same type of liver. (Chicken liver)

Control variable 4: The length of time needed for measuring the catalase reaction. I will keep it the same by measuring every reaction for 1 minute.

Control variable 5: The amount of the hydrogen peroxide. I will keep it same by using the exact same amount of hydrogen peroxide in each trial. (20ml)

Materials:

• 150ml of 0.5% hydrogen peroxide • 150ml of 1.0% hydrogen peroxide • 150ml of 1.5% hydrogen peroxide • 45g of liver • 100ml Measuring Cylinder (x1) • Stopwatch (x1) • Electronic Balance (x1) • Tweezer (x1) • Scalpel (x1) • Dissecting Dish (x1) • Lab coat (x1)

Method:

1. Cut the liver into smaller pieces with scalpel and dissecting dish. 2. Measure 5g of liver by using electronic balance. 3. Pour 50ml of 0.5% hydrogen peroxide to cylinder. 4. Put 5g of liver into the cylinder. 5. Measure and record the total amount of solution (H202+liver+foam) after 1

minute by using a stopwatch. 6. Repeat the method 1-5 twice. 7. Repeat the method 1-5 three times using 1% hydrogen peroxide instead of 0.5%

hydrogen peroxide. 8. Repeat the method 1-5 three times using 1.5% hydrogen peroxide instead of

0.5% hydrogen peroxide.   Data Table: Total amount of the solution (H2O2+liver+foam) (ml)

H2O2 Concentration (%) Trial 1 Trial 2 Trial 3 Average

0.5 29.0 30.0 30.0 29.7 1.0 35.0 37.0 35.0 35.7 1.5 45.0 40.0 38.0 41.0

Graph:

Conclusion: As it can be seen in the table above, the higher concentration of H202 resulted in more total amount of solution including H202, liver and foam. My data is reliable because all the trials in each concentration show increasing total amount, as the concentration of hydrogen peroxide gets higher. Moreover, the difference between average values of all three concentrations is 6. Thus, my hypothesis “The higher concentration of the hydrogen peroxide, the faster the speed of the catalase reaction” was correct. The higher concentration results in the faster the speed of the catalase reaction because increasing concentration of substrate in higher concentration of H2O2 increases the chances of substrates to join with enzyme. Thereby, in my case, more oxygen foam is created in the reaction. Evaluation: Errors/Weaknesses in Your Method

Specific Effect on Your Data

Improvement to your method

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0.0  0.5  1.0  1.5  2.0 Total amou

nt of the

 solu.

on 

(H2O

2+liver+foa

m) (ml)  

H2O2 Concentra.on (%) 

H202 Concentra.on .vs. Amount of Oxygen Produced (Average) 

1. In the beginning of the experiment, we used 50ml of hydrogen peroxide for each trial. However, 50ml of hydrogen peroxide was too much to see the definite difference between each concentration.

The difference between each concentration didn’t vary much. Therefore, we couldn’t get any pattern or trend.

We used 20ml of hydrogen peroxide instead of 50ml of hydrogen peroxide and this gave the obvious difference of amount of oxygen produced between each concentration.

2. Livers were cut into different size of pieces. This created more surface area of liver in certain trials. In the certain trials, the speed of catalase reaction could get faster.

Some trials, in which comparatively small pieces of liver were put into H2O2, would result in more oxygen produced. In our case, the total amount of solution would be higher.

Cutting the liver into as same size of pieces as possible in order to create same surface area of the liver.

3. Livers often stuck to the cylinder. It took more time for liver to be sunk into H202.

When livers stuck to the cylinder, it often resulted in less oxygen produced in that trial. This error reduced the reliability of the data.

Waiting till liver completely sinks into H2O2, and then starting the timing.

Other areas of investigation: If I get to do this experiment over, I want to change the input variable to different type of organ. This is because if I use different type of organ as my input variable, this experiment will give entirely different hypothesis and pattern from previous experiment with different concentration of hydrogen peroxide. Therefore, I would obtain entirely new scientific information.