Investigation the Factors that Affect Enzyme Controlled Reactions

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Investigation the Factors that Affect Enzyme Controlled Reactions

Planning

In this experiment I am going to try and find out the factors that

affect enzyme controlled reactions by using the Catalase in potato.

Enzymes are non-living and act as biological catalysts, which speed up

reactions. They can change shape if the temperature changes. Enzymes

are made up of active sites (the lock) and only certain shaped

substrates can fit into them to cause a chemical reaction.

To work out this experiment, I am going to use a formula of:

2H2O2-using catalase to become 2H2O+O2

I will use a set of five pH's to get my readings from the collected

oxygen. The amount of oxygen is directly related to the rate of

catalase activity. Factors affecting the rate of an enzyme-controlled

reaction are the independent; pH buffer and the controlled ones;

temperature, substrate concentration, time (rate of reaction), and

enzyme concentration.

The factor I am going to investigate is an investigation into the

effects of pH on the breakdown of H2O2 by catalase. To make the

investigation fair I'm going to control my variables. To control pH I

will use a buffer which will always be 5cm3, the substrate

concentration will stay the same every time, this means the volume of

H2O2 (hydrogen peroxide) will always be 5cm3 each time, the tests will

all be done at room temperature, the tests will be repeated to get an

average and my weight of potato will be the same for each of the

experiments.

Potato is good substance because it contains many active sites to

react with. I will be changing the pH in order to measure the effects

on the rate of catalase activity. In this experiment the five pH's I

will be using are: pH2, pH4, pH6, pH8 and pH 10.

At low pH's the enzymes are denatured because the pH interferes with

the bonding of the amino acids and the shape of the active site is

changed. As you increase the pH, the enzymes and substrates gain more

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