Investigation 5: PART I
Action of the enzyme catalase

Group:_________ Arrival date: 17th March
The members: ________ _______ ________ _________

INTRODUCTION:

The enzyme catalase – present in peroksisome- breaks down hydrogen
peroxide (H

2

O

2

) into water and oxygen: 2H

2

O

2

–2H

2

O + O

2

Hydrogen peroxide is formed in our organisms as a by-product of various
chemical reactions in living cells. It is toxic, and it were not immediately
broken down by the cells it would destroy them. This investigation presents
the action of catalase in a test tube. Liver that neutralizes toxins in the
organism is a rich source of this enzyme.

REQUIREMENTS
fresh liver
heart
pear

hydrogen peroxide (3%)
demineralized water

scale
mortar
test tubes
wooden spatulas
burner

Caution:
Be careful with hydrogen peroxide; it’s corrosive and may
burn the skin

PROCEDURE
(1) Take a piece of liver (10g), place it in a mortar along with
a little sand and grind it up.
Add 100 ml of water.
Pour into the test tube 1 ml of the above mixture
Add some drops (1 ml) of hydrogen peroxide and observe
prospective reaction. Check if temperature of the
dilution has changed (touch the testube with your hand
or use termometer).
After all put burning wooden spatule inside the test tube
(2) Repeat the steps for heart and pear. This will help you to
determine if catalase occurs in other organs and tissues
besides liver

1) Construct research problem for the first part of the expriment.
2) Construct hypothesis for the second part
3) Present your observations:
(a) Has the temperature of the dilution changed during the experiment.
if yes, answer the question if it decreased or increased.
(b) What has happend when you put the burning stick into the test tube
(c) Answer the following questions:
Why the temperature of the solution has changed?
Why the intensity of burning has changed after putting the wooden
spatule inside the test tube?
Is the enzyme specific? Did you observe an differences in catalase
action? If yes, explain why.

4) Fill in the table

Organs / tissues

How it reacts
with
hydrogen
peroxide

liver

chicken heart

pear

(5) Draw conclusions