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Catalase Investigation

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BIOLOGY GCSE PRACTICAL ASSESMENT 1. Our investigation is to find the rate of catalase activity. Catalase is an enzyme, which in this case is used to break down Hydrogen Peroxide. SUBSTRATE ENZYME PRODUCTS 2H�0� Catalase 2H�0 + 0� Enzymes are catalysts, which means that they are used to speed up reactions. They are not changed or used up in reactions at all. They have molecules with a 3-D shape and they work best at about a pH of 7 because, as they are proteins, they are denatured by very acid and alkaline conditions. As they are proteins they are also denatured by high temperatures. They work quickest at their optimum temperatures (the best kind of environment suitable for them). It is the yeast that makes the catalase. Yeast is a living cell (it is a fungi). Inside the yeast hydrogen peroxide is produced and as it is toxic, the yeast also makes the enzyme (catalase) to break down the Hydrogen Peroxide (substrate). Catalase is located in the cytoplasm of cells. In the cytoplasm they control the chemical reactions occurring inside the cell. Enzymes are specific and so only one type of enzyme will only break down one particular type of substrate. ...read more.


3. This is the write up for my preliminary work. The reason for writing this is to give you an idea of what I am going to do and to tell you precisely how to do it. AIM The aim of this experiment is to find out the rate of catalase activity. SAFETY During the whole of this experiment I wore safety glasses for eye protection in case there happened to be a spillage and I got some hydrogen peroxide in my eye. As I was working in the science lab I had to follow the main lab rules, such as Do Not Eat Or Drink In The Lab. I also had to be very careful, as the hydrogen peroxide was corrosive. EQUIPMENT Here is the list of equipment that is needed to carry out this experiment CONICAL FLASK BEAKER SYRINGE BUNG 2 DELIVERY TUBES MEASURING CYLINDER 20 cm� HYDROGEN PEROXIDE 2 ml YEAST SUSPENSION (CATALASE) 200 ml WATER DIAGRAM METHOD I set up the equipment as it is shown in the diagram above. I first got a conical flask and put 20 cm� of hydrogen peroxide in it. The concentration of the hydrogen peroxide was 20 volumes, which was the maximum concentration I was allowed to use. ...read more.


* To vary the variable, which I chose, all I have to do is add twice the amount of water, which is already in the beaker, to the hydrogen peroxide. This will change the concentration of it and so if we add twice the amount of water to 100% concentration of hydrogen peroxide it will change to 50% concentration of hydrogen peroxide. * Each time I vary the variable I will be halving the concentration each time so it will first be 100% and then it will be varied to 50%, 25%, 12.5% and then finally 6.25%. * During the experiment I will be measuring how many seconds it takes for the mixture of catalase (yeast suspension) and hydrogen peroxide to produce oxygen and displace 25 ml of water in a measuring cylinder. * During this experiment I will wear safety glasses for eye protection in case there happens to be a spillage and I get some hydrogen peroxide in my eye. As I am going to work in the science lab I have to follow the main lab rules, such as Do Not Eat Or Drink In The Lab. I also have to be very careful, as the hydrogen peroxide is corrosive. * * * * Nadeem Arshad 1 ...read more.

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