P10 CATALASA

INTRODUCTION

Catalase is an enzyme that has the function of destroying the peroxide of hydrogen, which is a product of biological oxidation, to be become in water and oxygen.

The peroxide of hydrogen protects us from microorganisms, like anaerobic microorganisms. But because of the peroxide of hydrogen is toxic, the catalase has to act.

OBJECTIVE

• To know the quantity of catalase that there is in meat, in this experiment a liver, or in a vegetable, in this case a potato. 
• To observe the reaction of catalase and what happens if we boil the meat and potato.

MATERIAL

• Peroxide of hydrogen ( H₂O₂)
• Distilled water
• Bunsen burner
• A piece of a liver and a piece of potato
• A beaker (250 mL)
• 4 beakers (100 mL)
• A knife, scissors
• Latex gloves 
• 2 Test tubes with cork stopper.

PROCEDURE
We have done three different experiments.

PROCEDURE OF THE FIRST

• We cut into pieces of liver and potato.
• We take a 250 mL Beaker and we add the pieces, then we put in distilled water until it recovers all the pieces.
• Finally, we boil the beaker in a Bunsen burner. We observe the reaction.

RESULTS:  It has been a reaction, with effervescence when the water has boiled. 

CONCLUSIONS: The catalase of this tissues has denaturated, because of the change in the temperature, it has left with a primary structure and with no function. 


PROCEDURE OF THE SECOND 

We take four 100mL Beakers and then we put inside:

• In the first: we put a piece of the liver with 5 mL of H₂O₂.
• In the second: we put a piece of the potato with 5 mL of H₂O₂.
• In the third: we put a piece of the boiled potato with 5 ml of H₂O₂.
• In the fourth: we put a piece of the boiled liver with 5 ml of H₂O₂.

RESULTS: in the beakers that have been boiled , there is no action by the catalase, no effervescence. 

CONCLUSIONS: in the tissues that have been denatured, they don't have a reaction with the oxygenate water, because the catalase has lost the function. 


PROCEDURE OF THE THIRD 

• ·   First we take two test tubes with a cork stopper, with two perforations  in each of them, one to put a thermometer and the other to let the oxygen pass. And we put them in a beaker.
• ·   We add in a tube a piece of potato and in the other a piece of the liver.
• ·   Finally, we pour distilled water.
• ·   We close the test tubes and we observe the reactions. 

RESULTS: in the test tube with a piece of liver, the temperature has increased 10 degrees, but in the test with a piece of a potato, the temperature has almost increased nothing. 

CONCLUSIONS : the tissues from the animals have more catalose than the vegetables. In the vegetables the catalose produces a little efervescence, but the exothermic reaction is not as in the animals. 

QUESTIONS 

1.    What happens when the tissues are boiled? 
The tissues will lose the quaternary, the tertiary and secondary structure,
so the proteins are left with a primary structure, without function. That is 
called denaturation and it’s caused because of changes in thetemperature,
in the pH...

2.    What happens with the temperature?

The reaction of catalase is exothermal. In animals the temperature in the previous experiment (the third), in the liver has increased ten degrees and in the potato almost nothing; when it acts with oxygenate water. 

3.    Why the peroxide of hydrogen (oxygenated water) is a good disinfectant?

The oxygenate water is used to cure wounds because is a strong oxidant; it acts on the microorganisms, as anaerobes or aerobics, it destroys the extern membranes of them, therefore, their existence. The oxygen gets free when it acts with organic material and it produces effervescence.

4.    Do a graphic with the results of the third experiment.

5. Which tissue has more catalase? The liver has more catalase
because it has produced more effervescence and temperature has
increased much more than in the potato, the exothermic reaction is
stronger too. 

 

P9 BIURET TEST

OBJECTIVES

We want to observe the quantity of proteins of eggs and milk, and of its different types and parts.

MATERIAL

·         Tube rack

·         5 test tubes

·         5 beakers 250 mL

·         Pipette

·         Distilled water

·         An egg

·         Milk: skimmed and whole milk

·         Soy juice

·         CuCo₄

·         NaOH

·         Weighing machine

·         Spatula

·         Glass stirring

·         Dropper

PROCEDURE

I will divide this experiment in two parts, to make it strictly.

PART 1

1.    We take 5 beakers and we indicate which substance we are going to add on it, and we put 100 mL of distilled water in every beaker.

2.    After that, we add 10 mL of one of those substances (soy milk, skimmed milk, whole milk, egg yolk, the egg white) in every beaker, with the help of a pipette.

3.    Then we remove it with the help of a glass stirring.

PART 2

1.    We take five test tubes and we indicate again which substance we are going to add on it, the content of each beaker.

2.    We add in every test tube 2 mL of one of the beakers, different in each tube.

3.    We put 2 mL of Na OH dissolution 20% (20 g of NaOH and 80 g of distilled water).

4.    Finally, we add 5 drops of CuCO4 1% dissolution (1 g of CuCO4 and 99 g of distilled water).

RESULTS  

If we observe the results are:

1.    Egg yolk. (colour dark purple)

2.    Soy juice. (colour purple)

3.    The white egg.  (colour dark blue)

4.    The whole milk.(colour blue)

5.    The skimmed milk. (colour blue- grey)

CONCLUSIONS

Biuret Test is used to reveal the quantity of proteins that a substance has, depending on the result colour.

The substance that has more quantity of proteins is which is close to the colour black, then the colour purple, blue. The substance with the less quantity of proteins is close to the colour grey. 

In the results is already arranged from which has more proteins to which has minus quantity of proteins.