Method
- Set up apparatus as shown below
- put catalyse extract into a syringe and put in water at set temperature for about 5 minutes for catalyse extract to heat up/cool down to correct temperature
- put 10cm3³ of the hydrogen peroxide into the conical flask
- put 10cm3³ of catalyse extract in with the hydrogen peroxide
- Time for one and a half minutes then take tube out of beehive shelf
- The oxygen produced by the reaction will pass through the tube into the measuring cylinder giving a measure of the rate of reaction
- Record the volume of the oxygen released
- Repeat three times for six different temperatures
Diagrams
Preliminary Work
Using results from preliminary experiments I have decided to use the temperatures 10˚C, 20˚C, 30˚C, 40˚C and 50˚C because that way I will be able to get a wide range of results from the temperatures that will be too cold for the catalyse and too hot so I can get the complete range. Using preliminary results I am using 10V hydrogen peroxide and 10cm3³ of potato puree to get results that will not exceed 100cm3³ and will be large enough to get more accurate and easy to measure results.
Fair Test
To make sure that the experiment is a fair test I will keep the same:
- Volume of Potato puree
- Volume of hydrogen peroxide
- Time reaction is allowed to run on for
- The same starting volume of oxygen in the measuring cylinder
- Same length of tube
I will also keep all the syringes in the water bath for 5mins to give the catalyse time to de-nature if it will do so.
Results
Conclusion
The fastest rate of reaction occurred at 20˚C. This is as I predicted because the enzyme works at this temperature in the potato under the ground in its natural environment and so work at its best at this temperature. By 60˚C it is clear that the reaction has stopped, this is because at this temperature the enzyme has denatured because of all the energy it has distorted the active site of it and the lock and key action of Catalyse can no longer occur.
Evaluation
In general the results I obtained were very reliable and kept with a distinct pattern. The only result that was an anomaly was at 60˚C on the second test which gave 10 cm3; it crosses in to the 50˚C results.
To improve on my experiment I could have left the syringes in the water bath for longer to provide far more reliable results and make sure that the enzyme was de natured. I could also have done a test at just over 0˚C to discover at what temperature the Catalyse denatures.
To extend my results I could try different temperatures between 50˚C and 60˚C to find the exact temperature it denatures from at the higher temperatures. I could also see how the pH effects the reaction or how the concentration of hydrogen peroxide effect the rate of reaction.
