Reports

Practical 7 Investigation of the Enzymatic Effects of Materials on Hydrogen Peroxide Solution  __________________________________________________________________________ Objective: To investigates the enzymatic effect of various materials in the hydrogen peroxide solution. Apparatus & Equipment: Beaker Water bath Glass rod

Boiling tubes Pen knife Parafilm

Materials: Fresh Liver Manganese dioxide Wood splints **Caution: **Caution:

Potato cubes Hydrogen peroxide**

Hydrogen peroxide perox ide is formed continuou s sly ly as a by by-produc -produc t of chemical reac reactions tions in liv living ing cells; it is a very toxic (pois onous ) substance. substanc e.

Procedures: Wear gloves when handling liver tissue. One pair of gloves per group to prevent wastage. 1.

Label six fresh empty boiling tubes 1, 2, 3, 4, 5, 6.

2.

Cut the liver provided into three pieces of roughly 0.8 cm x 0.8 cm x 0.5 cm.

3.

Place one piece of liver into tube tube 1.

4.

Place the second piece of liver into the tube 2. Place tube 2 in the boiling hot water for about five minutes. Remove from boiling water and let cool.

5.

Put the third piece of liver into test tube. Mash it gently into a pulp with glass rod.

6.

Cut potato cubes of roughly 0.8 cm x 0.8 cm x 0.5 cm. Place one cube into a tube 4.

7.

Measure two portions portions of 0.5 g of manganese dioxide powder. Pour each portion into tube 5 and tube 6.

8.

Put tube 6 in boiling water for five minutes. Remove from boiling water and let cool.

9.

Prepare another six fresh empty test tubes. Put 5 cm of hydrogen peroxide into each of them.

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10. Quickly add hydrogen peroxide into the test tubes 1, 2, 3, 4, 5, and 6. 11. Using the parafilm provided, stretch it quickly and seal the mouth of the test tubes. 12. Leave for 20 minutes or till you see quite a lot of gas being produced in some test tubes as evidenced by the bulging of parafilm from the test tube mouths. 13. Insert a glowing splint (flame extinguished but glow remains) into each tube one at a time by just penetrating the parafilm with it.

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Why is it important to test each test tube at about the same time or at least without too much difference in the duration of sealing among the tubes? 14. Record all your observations in the table. Record your observations on each tube immediately after the reaction has started. Table 1:

Tube 1 2 3

Contents with 5 cm hydrogen peroxide

3

Before using wood splint

After  using wood splint

Fresh liver Boiled liver (cooled) Pulped liver

4

Potato cube

5

Manganese dioxide (untreated)

6

Observations

Boiled manganese dioxide (cooled after heating)

Washing up Thoroughly wash and scrubbed all apparatus containing liver pieces with Dettol® solution provided to rid it of unpleasant odours. Results and discussions: In your report, be sure to address the following: 1.

What is the equation of the reaction observed?

2.

What plant or animal organelle is involved?

3.

What effect does pulping the liver have upon the reaction? Account for this.

4.

What effect does boiling the liver have upon the reaction? Account for this.

5.

What were the differences between the reactions with fresh liver and with fresh potato cubes?  Account for these differences.

6.

What were the differences between the effects on the reaction of boiling the liver and heating the manganese dioxide? Account for these differences.

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