The Effect of Temperature On the Enzyme Catalase

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THE EFFECT OF TEMPERATURE ON THE ENZYME CATALASE

PLAN

AIM

My input variable for this investigation is the temperature of the hydrogen peroxide solution. My output variable will be the rate of reaction of the enzyme catalase in the potato, i.e. the amount of oxygen given off. I will investigate how the rate of reaction of catalase varies as its temperature is varied. This will be shown by the amount of oxygen given off within a certain time.

PREDICTION

I predict that as you increase the temperature of the enzyme catalase the amount of oxygen given off will increase (i.e. the rate of reaction of catalase will increase). This is because catalase speeds up the chemical reaction H202 - - - -H20+02. Therefore, as you increase the temperature, catalase will gain more and more activation energy and so the speed of reaction will increase.

As the temperature of catalase is increased by 10?C I predict that the rate of reaction will roughly double, i.e. double the amount of O2 will be produced.

When a solution is heated, the particles move around quicker because they have more energy. Because they travel faster, they collide more often. At low temperatures, the particles do not always crash hard enough together to start a reaction. However, at higher temperatures, the particles crash much harder and therefore more reactions are started.

Above a certain temperature, I predict that the amount of oxygen given off will decrease rapidly and then eventually stop altogether. This temperature will be just over 40?C. At a temperature above 40?C, enzymes stop working as well and eventually at a temperature of around 50? - 60?C, stop working completely. This is because they become denatured. Catalase speeds up the reaction because it has special receptors with a certain shape on its surface. The hydrogen peroxide molecules are able to fit into them and then become broken. If the temperature gets to high then the shape of these receptors become deformed. Once deformed the hydrogen peroxide molecules can no longer fit into them and can therefore not be broken. Therefore, any oxygen given off at a very high temperature when the enzyme is denatured will be the natural breaking up of hydrogen peroxide. Not the cause of catalase!

A FAIR TEST

Other variables than temperature that could affect the outcome variable could be

I. The concentration of the enzyme.

II. The concentration and volume of the reactant.
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III. The surface area, type and the mass of the potato.

IV. The method of collecting the oxygen given off.

In order to insure that my investigation is a fair test I will make sure that each of the above variables are constant each time I carry out the experiment.

METHOD AND SAFETY

Cut out a few pieces of potato using a 10mm cork borer. Using a knife and ruler to measure and cut these pieces into 12 smaller pieces, with a length of 30mm each.

Get twelve test tubes and two test ...

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