Biology Experiment report

THE EFFECT OF CHANGE IN pH ON THE ACTIVITY OF ENZYMES

Introduction:
Enzymes are catalysts that speed up, and control chemical reactions within a cell and break down complex molecules into smaller ones. Some of the chemical reactions that take place in the body produce toxic by-products which need to be converted. The liver produces hydrogen peroxide, which is extremely poisonous. When the catalase comes in contact with the hydrogen peroxide, it is broken down into water and oxygen.

Aim:

The aim is to investigate and determine the effect of change in pH on the activity of the enzymes catalase.

Equipment:

Test tubes
Test tube rack
Pipettes
Stopwatch
Ruler
Pen
Safety goggles
Gloves

Materials:
Liver pureed
3% of hydrogen peroxide (H2O2) with few drops of detergent

Safety:
Hydrogen peroxide is corrosive therefore you should wear gloves and safety goggles when handling it

Table of Variables

Dependent
Independent
Controlled
Amount of bubbles produced pH of substrate
Amount of liver (pureed)
Temperature (37 degrees celcius)
Amount of detergent concentration of H2O2

Method:

Part 1 – setting up control

1. Add 3mL of pureed liver to test a tube
2. Add 3mL of hydrogen peroxide (H2O2) to the liver and start stop watch
3. Time how long it takes for the bubbles to reach the top of the test tube – control (3.95 seconds)

Part 2 -

1 2 3 4

Test tube Test tube rack Liver pureed

1. Set up approach as shown above
2. To test tube 1, add 3mL of hydrogen peroxide (H2O2) start stop watch
3. Measure height that the bubbles reached with a ruler and record it with a pen
4. Repeat steps 1-3 for the remainder of the test tubes
5.