To investigate the effect of pH on the rate of enzyme activity

Question 1

What is catalase?

Answer 1

It is an enzyme found in celery and liver.

Question 2

What does the enzyme catalase convert into what?

Answer 2

It converts the toxic substance hydrogen peroxide (H2O2) into water and oxygen.

Question 3

What happens when catalase is used with oxygen and washing up liquid?

Answer 3

It creates foam

Question 4

What does the volume of the foam indicate?

Answer 4

It indicates the activity of the enzyme

Question 5

Name the 14 steps required in the experiment to investigate the effect of pH on the rate of enzyme activity

Answer 5

1. Place pH buffer solution 4 in a graduated cylinder.
2. Add one drop of washing-up liquid to graduated cylinder.
3. Blend celery in water for under 6 seconds (any more and enzymes will be destroyed). Filter using coffee filter paper.
4. Add some of the filtrate to the graduated cylinder.
5. Add some hydrogen peroxide to a smaller graduated cylinder.
6. Put both graduated cylinders in a water bath of 25 degrees C for a few minutes.
7. Remove and pour hydrogen peroxide into the graduated cylinder containing the blended celery.
8. Note and record the volume at the top of the foam after 2 minutes.
9. Calculate the volume of the foam produced.
10. Repeat past steps using pH buffers 7, 10 and 13.
11. record the results for all and make a table showing them.
12. Draw a graph of the results.
13. Note that catalase has its maximum activity at pH 9 or 10.
14. As controls, repeat each procedure but do not add the blended celery or add blended celery that has been boiled (enzyme denatured)