Aim: To investigate the effect of PH on the activity of the enzyme catalase
Hypothesis: The enzyme’s optimum PH will be 7.5 as 7.5 is basic.
Changes in pH may not only affect the shape of an enzyme but it may also change the shape or change properties of the substrate so that either the substrate cannot bind to the active site or it cannot undergo catalysis. Extremes in pH can denature enzymes.
Catalase is a common enzyme found in nearly all living organisms that are exposed to oxygen, where it functions to catalyse the decomposition of hydrogen peroxide to water and oxygen. Catalase is made up of four polypeptide chains. The optimum pH for human catalase is ...view middle of the document...
4. Students recorded the volume of 02 collected in the measuring cylinder every minute for five minutes.
5. Students repeated the experiment using the 3 other buffer solutions and using fresh potato each time.
6. Students repeated the experiment using the buffer solution and H2O2 only without any potatoes added as a control.
7. Students repeated the experiment 3-4 times and calculated the average result for each pH value.
Independent variable: pH of the sodium phosphate buffer solution
Dependent: The water level in the 100ml measuring cylinder.
Controlled: ph of hydrogen peroxide solution, amount of hydrogen peroxide solution, diameter and length of the potatoes, temperature of the water.
The largest amount of 02 was produced with buffer solution of pH 7.5. At other pH, O2 production was far less. This suggests that catalase has an optimum pH of 7.5.
1. What is the purpose of the control experiment?
The control experiment is needed to compare the results and show that the results are inky due to the independent variable and nothing else. It ensures the validity of the results.
2. How was the waste material disposed of?
It was put in an inorganic jar
3. Outline the use of destructive/non-destructive test un this experiment
• Hydrogen peroxide
• Test tube
• Measuring cylinder