Hypothesis: I think at 0 C the amylase will be defective because there is no energy for it to function. When the temperature is increased the amylase will begin to breakdown the starch but very slowly. At its optimum temperature (40°C). It will work at a very high rate and almost all starch will be broken down. When the temperature is increased to 50°C or above the amylase will become deformed and cease to function.
Scientific Explanation:
Safety: Working with a temperature of 60°C if you are not careful this can scold you.
Working with a water bath be careful the water and electricity do not mix.
Working with glassware – do not break and leave injuries can occur.
Variables:
Independent – Temperature
Dependent - Rate of Enzyme
Controlled - Amount of amylase
- Concentration of amylase
- Amount of starch
- Concentration of starch
- Water level in bath
- Amount of iodine (3 drops)
- pH level in water bath
Fair Test - Do not experiment three times and find an
average from results.
- See variables: Controlled
Measurement - Range of measurements – 0 to 60°C
- Interval – Rise by 10°C
Equipment List - Thermometer (measures temperature)
- Measuring Cylinder (measures volume)
- Stop watches (measures time)
- Water Bath
- Iodine
- Pipits
- Test Tube
- Amylase
- Starch
- Iodine
- White Tile
- Universal Indicator
PLAN
Preliminary Work:
This is an experiment I have done previous experiment:-
I am not using 10ml of starch to 1ml amylase because it takes far too long to breakdown.
I am not using 3ml of starch to 1ml of amylase because it breaks down too quick.
The best choice would be to use 5ml of starch to 1ml of amylase, however because I am taking drops out to test whether the solution has starch I am going to double this to 10ml starch and 2ml amylase so it does not run out.
Two different measuring cylinders will be used for measuring starch and amylase.
Method
Step 1 Gather all equipment (see equipment list)
Step 2 Put 3 drops of iodine in each groove of white tile.
Step 3 Put 10mls of starch in one test tube and 2 mils of amylase in another.
Step 4 Put both in a water bath till they have reached a required temperature.
Step 5 Mix the amylase and starch in one test tube.
Step 6 Take a sample of the mixture using the pipit and drop in iodine every 20 seconds checking to see whether starch is present.
Step 7 Do experiment (steps 1-6) three times for this particular temperature.
Step 8 Do steps 1 – 7 for each temperature.
Table of Results
CONCLUSION
In my results table, it is noted that when the temperature rises, the rate of reaction increases very quickly but when the temperature gets beyond
40°C (optimum temperature), the rate of reaction declines rapidly. At 0°C no reaction takes place after 15 minutes. Due to past knowledge of enzymes I know they cease to function so it is assumed there is not reaction. At 40°C the rate of reaction is at its best with a reaction rate of 0.5000. It then drops dramatically to 0.0167 at a temperature of 50°C. At 60°C the same result as 0°C has occurred due to the deformation by the high temperature. On my graph the line of best fit has a gradually rising slope at 40°C plus. The rate of reaction decline and a steep fall is seen from 40°C (0.800) to 60°C (0.0000).
This is because:
- The benefic energy allows enzymes and substrates in the ‘lock and key’ sequence.
- 40°C is the optimum temperature because it is closed to body temperature (37°C) where amylase is found. This is why the rate of reaction is at its peak.
- Though more heat gives more energy any temperature above 40°C (optimum) causes the amylase to become deformed.
Also see scientific explanation.
EVALUATION
My experiment went exactly to plan and I had not real problem with it. I feel my best results were at 0°C, 10°C, 40°C and 60°C because all three results were the same so I presume they were most accurate e.g. 0°C results were 00, 00, 00 and 40°C results were 20, 20, 20. The results of 0°C and 60°C were assumed infinite (00) after 15 minutes however, I am not sure if it was enough to assume infinite. May be another 15 minutes would have helped me to confirm the results. I still believe they were correct because at 0°C there is no energy and t 60°C the enzyme active site is denatured disabling the substrate from fitting.
A high percentage of the points on my graph was close to the line of best fit. The anomalous result was 20°C. It is rear room temperature yet the results from this water both were very unstable. Reasons for this may include contaminations to solution. pH may have changed or an inaccurate amount of substance (amylase and starch).
