The diagram above shows the effect of amylase as the temperature differentiates. The grey box represents the starch and the ‘C’ shaped object represents the amylase. The starch bonds with the amylase at an area called the Active site. Once it has bonded with the enzyme the starch is broken up into glucose. The active site only allows starch to bond nothing else will fit! (Diagram A). When the temperature is increased to around 45-550c the enzyme becomes denatured. As a result the active site changes shape and no longer allows the starch to bond with it, as the starch molecule can’t fit into the amylase (Diagram B). This results in a lower rate of reaction.
EQUIPMENT
- 2% amylase
- 2% starch
-
Water baths (20, 30, 40, 500c)
- Syringes (to measure quantity of starch/amylase)
- Iodine
- Pitted tiles
- Stop-clock
- Pipette
METHOD
- Collect The Apparatus
- Place 5ml Of Starch And 5 Ml Of Amylase Into Two Test-Tubes. Place the Test Tubes Into A Water Bath.
- Leave The Test Tubes There For 2 Minutes, And then Mix Them Together. (Start The Timer)
- Place A Few Drops Of Iodine Into Each Pit Of The Tile.
- After 30 Seconds Take A Sample Of The Starch And Amylase And Place it In The First Pit. Each Pit Will Represent 30 Seconds.
- Keep Taking Samples Every 30 Seconds Until The Sample Goes Brown.
- Make A Note Of The Time.
- Repeat Using A Different Temperature.
SAFETY
To make sure I kept this experiment hazard free I used important safety procedures. The main one was to wear safety goggles to protect my eyes from the chemicals as they can damage your eyes. In addition to this I also made sure that my skin did not come into contact with the amylase, as this is an irritant. I made sure not to get any water onto the electrical equipment as we were using water baths that were run on electricity. The final but still important point is to locate the eye treatment in case of an emergency.
FAIRTEST
To obtain the best results I had to make sure that I did a fair test. I did this simply by making sure that I used the same amount of starch as I did amylase throughout the experiment, also I didn’t mix the starch and amylase until they acclimatised to the temperature of the water. I did this by leaving the starch and amylase in different test tubes in the same temperature for the same amount of time, and then mixed them into the same test-tube. I also made sure that the water bath stayed at the same constant temperature.
RESULTS
ANALYSING
In total I done this experiment six times all at different temperatures, these were at 0,10,20,30,40,50 and 60 degrees. The first sets of tests were done at a temperature of 0 degrees, this took 12.6 minutes, but as the temperature rose the time it took to react quickened. At 30 degrees the time to react only took 5 minutes this time kept rising until it reached its optimum temperature/point. This temperature was at 40 degrees Celsius. Once it reached this point the time that the enzyme took to react steadily declined from 3.2 minutes at 40 degrees, until 9.6 minutes at 60 degrees. I also predict that the time would of kept falling until no reaction took place, but we had to stop our experiment at 60 degrees. There are some trends in the data as it is a curved graph; all results went as planed apart from one anomaly. This anomaly occurred at 20 degrees, but other than this the experiment went without a problem, the way I expected. What i predicted to happen in my hypothesis was correct, the time the reaction took to react decreased, when the heat rose then when it got to 40 degrees (Body temperature) it started to take longer periods of time to react.
My results are simple the hotter the temperature the quicker the rate of reaction`
EVALUATING
My original hypothesis was correct, ‘I believe that the heat will affect the enzyme as the temperature is changed. I fell that the breakdown of starch will be quicker as the heat is increased. I think that the optimal temperature level will be 30-40 degrees, which is around body temperature.’ I knew that this would be a rough guide to what would happen, as this reaction takes place inside the human body and the human body is around 40 degrees hot, it made sense that this reaction would work better in the environment that it has to work in. My experiment didn’t go without and problems, I recorded an anomaly in my set of results At 20 degrees. I fell that this anomaly occurred because to see if the reaction had finished we had to see if the mixture turned brown when mixed with iodine, but there are many shades of brown. This didn’t help the fact that we had to use just are eye to try and judge when the mixture did turn brown, which is not very accurate. There are many was that we could have improved this experiment and made it more accurate, the main thing we could have done is used a light sensor instead of human eyes. The spectrometer would have been 100% accurate in defining the shade of brown and ultimately told us when the amylase and starch had truly mixed, this is the only way that this experiment could have been done with such a degree of accuracy. I could take this experiment to a greater depth by different means. I could test the effect of amylase in a cold-blooded reptile and see if the rate of reaction differs from that of the rate of reaction in us humans. But this will only reinforce my knowledge of the optimum temperature the amylase will react at.
