The aim of this experiment is to find out the effect of temperature on catalase or hydrogen peroxide. This will enable us to tell at what temperature hydrogen peroxide is most efficient. This (degradation) reaction will help us determine some of the catalase’s different attributes.
In this experiment it would be safe to hypothesise that no activity would take place at 1 to 20 degrees. It would be probable that a little activity would take place around 40 degrees. When the water gets to around 60+ the oxygen bubbles start to froth.
It is almost certain that this will happen due to the behaviour of the atom. This means that the hotter the water gets the more active the water molecules become. Thus the colder the water gets the less active the water becomes. Another theory is that different things adapt according to their habitat. Therefore, catalase would be most active at around 37 degrees body temperature. This means that in this experiment catalase would be most active in the water bath that is at 40 degrees Celsius.
Before the experiment could be started the following apparatus needed to be obtained:
Water Baths at 3,20,40 and 60 degrees Celsius
Now that all this apparatus has been obtained, it is possible to start the experiment. Eight test tubes will be required because the experiment is being done twice in each water bath.
Use a marker pen to mark the specific temperature on the test tubes so as to make sure that there are no possible errors. Now place these test tubes in a test tube rack. Take the cork borer no. 4, and take a cylinder of potato using the cork borer. Do this until you have eight cylinders. If there are any cylinders that are uneven in size, then take the cylinder again using the cork borer. Now that you have good cylinders, cut them to equal length equal to 1.5cms. cubed. Once this has been done, put each potato cylinder in a test tube. Now it is almost time to start the experiment, so have a stop- watch at the ready. Pour 5cms cubed of hydrogen peroxide (H2O2) into each test tube.
Now go to the first water bath that is 3 degrees Celsius and take a pipette and pour 10 drops of detergent into the first 2 test tubes (the test tubes that are labelled 3 degrees Celsius). Once you have done this, immediately start the stopwatch and simultaneously put the 2 tubes into the water bath. Repeat this process for the next 3 water baths. Although only 1 stopwatch has been used, the time will be fairly accurate since a delay has been created. When 5 minutes is up go to the first water bath with a ruler and measure the amount of froth on each test tube.
Experiment No.Temperature (oC)Height of Froth (cm)Average Height of Froth (cm)
In conclusion to this experiment, it is evident that catalase is most active at 40 degrees Celsius. There is a trend in a graph that shows the froth increases up towards 40 degrees Celsius and dips when reaching 60 degrees Celsius. It is not just a case of the Enzymes activity decreasing it becomes denatured shortly after it reaches it’s optimum level of activity.
In this evaluation, the flaws and the limitations of this experiment will be outlined. The procedures in this experiment were very effective. Unlike many other experiments the control of the variables was without fault, because a machine was controlling them, i.e. the water bath. There were not many limitations of equipment, and the only way the equipment could have been improved would have been to have the experiment monitored by computer. All the sources of error in this experiment were with the non-variables.
Firstly, there was no way of being sure that each potato was the exact same length or mass. A way of improving this would be using a guillotine-type device, meaning that the potatoes were at least the exact same length since they were cut at equal angles all together. Another flaw is the amount of H2O2 poured into each separate test tube. This is cannot be improved upon unless done by machine. Other sources of error that could only have been improved upon by machine are height of
froth, and amount of detergent. A major defect that could have affected the results is the timing. This is because of the delay system used. The only way that the delay system could have worked like clockwork is if it took the exact same time to measure froth as to pour detergent. There are two ways of improving this. The first is to make the experiment last longer. This would mean that it would not matter if there were a few seconds difference in the times, because no more froth could have been produced. The second is that if the experiment was timed separately for each bath.