In our biology class, we started studying enzymes. In order to see how the Catalase works, our teacher told us to do an experiment.

AIM: how temperature affects the activity of catalase.

This was the task:

1- Write down the equation of the chemical reaction in words and build a table to record your results.

2- The teacher provides you with:

a- 3 test tubes filled with hydrogen peroxide (substrate)

b- a piece of potato (source of catalase)

3- Cut the potato into 2 cubes of 0.5 cubic centimeters each. The third cube has already been prepared for you.

4- Place one cube and one test tube in the 1st water bath at 5°C for 2 minutes.

5- Place the cube into the test tube and leave it in the water bath for 2 minutes.

6- Measure the height of the foam produced.

7- Record the result in the table.

8- Repeat steps 4 to 7 with the other cubes.

9- Plot the information in a line-graph

a- Why did you leave the potato and the test tube in the water baths before the experiment?

b- State: – the independent variable

The temperature.

– the dependent variable

The height of the foam produced.

– two fixed variables

c- Describe the results shown in the graph.

d- At what temperature the enzyme works best?

At 30ºC.

e- What has happened at 100°C?

No foam is produced. There is no activity because at high temperatures the active site loses its shape, therefore the substrate doesn’t fit into the enzyme. The enzyme is denatured.