As amylase is created in the mouth it normally works at body temperature, 37 degrees C. Also because the enzyme is created in the mouth it works normally at the pH of the mouth, which is neutral (7).
Before I can carry out the investigation there is still one more thing that must be carried out. The Preliminary Investigation
Preliminary Investigation
The reason I must carry out a preliminary investigation is to:
- Help understand what we have to do in the full investigation
- And how to do it.
As the variable I am to change is temperature the other variables, such as pH, must be kept constant throughout the investigation to ensure the experiment is kept a fair test. For the preliminary investigation I used the same volume of starch and amylase as the full investigation, 10cm3 of starch solution and 2cm3 of amylase. As it is a preliminary investigation I tested for only one temperature, 40 degrees (about body temperature). I heated up a water bath to 40 degrees, and placed the two separate test tubes of starch and amylase to the beaker when the water was the right temperature and the Bunsen burner turned off. Waiting until each test tube had reached the required temperature I added the amylase to the starch. Then every minute a sample of the mixture was taken using a pipette, placed into a spotting tile and a drop of iodine added.
Using the information collected form the preliminary investigation I found that waiting 1 minute between taking samples of the mixture was too long and the colour change happened too quickly. Therefore I shall shorten the gap between taking samples to 30 seconds, hopefully giving sufficient examples of the colour change.
Full Investigation
Apparatus
-
10cm3 of Starch solution
-
2cm3 of Amylase
- 2 Test tubes
- Test tube rack
- Test tube holder
- Stop watch
- Beaker
-
125cm3 of water
- Iodine
- Spotting tiles
- Pipette
- 2 Syringes
- Benedict Solution
- Thermometer
- Goggles
- Ice
- Bunsen burner
- Tripod
- Heating Mat
- Splint
Plan
- Collect apparatus on list and set up as in diagram.
- Light the Bunsen burner and heat up the water until it reaches the required temperature.
- While the temperature is rising use a syringe to collect the starch and amylase.
- Add two drops of Iodine to each well of the spotting tile.
- When 40 degrees is reached shut off the Bunsen burner.
- Add the starch to the amylase and start a stopwatch at the very same time.
- Every 30 seconds add a drop or two of the solution to the Iodine in the spotting tile, using a pipette.
- Between each sample is taken, wash out the pipette to avoid contamination.
- Stop taking samples when the colour of Iodine stays orange-brown.
- To prove that a new substance is made add the remaining solution to a clean test tube, and add Benedict solution.
- Turn the Bunsen burner back on and place the new test tube in the water bath.
- Using the test tube holder to hold the test tube, heat the water bath to boiling point.
- If the solution turns brick red it means that glucose has formed.
- Repeat the experiment 2 more times to check the reliability of the results.
- The experiment should then be repeated at different temperatures. 0,10,20,30,50,60,70 and 80 degrees C. Including room temperature.
- Throughout the experiment change only the temperature and keep all other variables the same.
Variables to change Variables to keep the same
pH of the Starch and Amylase
Temperature Concentration
Amount of Starch and Amylase
Prediction
I predict that the amylase would break down the starch most effectively at 40oC, and with decreasing efficiency towards 0oC, at which the amylase would be unable to break down the starch at all. This is because body temperature is around 40oC, and enzymes are designed to work at this optimal temperature. At temperatures over 40oC, I predict, the amylase would begin to denature.
I predict the enzymes would denature at a high temperature because as the temperature increases the enzymes gain more energy, as heat is a form of energy. The atoms inside of the enzyme vibrate more because they have gained lots of energy, eventually they break the bonds holding them together and changing the shape of the enzyme. Causing it to be unable to fit the specific shape of the starch molecule.
Results
Graph
Conclusion
The results I have collected from my investigation backs up the prediction I made earlier. The optimum temperature for enzyme to work the most efficiently is 40 degrees C which is about body temperature, and that the further away you get from this temperature the longer the reaction takes until eventually the enzyme is unable to function properly at all.
Evaluation
The experiment worked well overall proving that optimum temperature for amylase is body temperature, round 40 degrees C. Ultimately the results turned out pretty well showing that 40 degrees is definitely the most efficient temperature as the starch is broken down the quickest.
I found one area that could be improved on but would not really be very cost-efficient. There would still be some solution left in the pipette even though I tried to wash it out to solve this I could have used a new pipette each time, but once again its not very cost- efficient.