Housewife A uses warm water to wash her clothes using washing liquid which contains added enzyme. The cleaning is more effective.
Using the same washing liquid as in situation 1, housewife B uses cold water to wash her clothes. The cleaning is less effective.
Based on both situations, design a laboratory experiment to study the effect of temperature on the rate of enzyme reaction.
The planning of your experiment must include the following aspects:
• Problem statement
• Objective of investigation
• List of apparatus and materials
• Technique used
• Experimental procedure
• Presentation of data
1. Aim of investigation
To study the effect of different temperatures on the rate of enzyme reaction on starch.
2. Problem statement
What are the effects of different temperatures on the rate of enzyme reaction on starch?
As the temperature increases, the rate of enzyme reaction on starch increases until the optimum temperature of 37oC.
Manipulated variable: Temperature
Responding variable : Time taken for the hydrolysis of starch to be completed
//Rate of enzyme reaction
Fixed variable : Volume/concentration of the amylase enzyme// Volume/
concentration of cooked starch
Test tube, beakers, thermometer, droppers, stopwatch, and white tile
Starch solution, water bath, salivary amylase, iodine solution (Salivary amylase and starch solution-must have)
6. Technique :
Record the time taken for the iodine solution to stop turning to blue-black colour/for complete hydrolysis of starch using a stop watch.
7. Procedure :
1. Measure 5ml of starch solution into a test tube.
2. Put the test tube containing starch solution in water bath at 37oC for 5 minutes.
3. Put another test tube containing 2 ml of salivary amylase in a water bath at 37oC for 5
4. Pour the salivary amylase into starch solution.
5. Put a drop of the mixture into a drop of iodine solution at interval of 1
6. Fix the volume of starch solution at 5 ml for all the experiments.
7. Fix the volume of salivary amylase at 2 ml for all the experiments.
8. Record the time taken for the iodine solution to remain yellow/ to stop
turning to blue-black colour using a stopwatch.
9. Repeat experiment at different temperature: 20oC, 30oC, 50oC, 60oC.
1. Ensure the temperature is stablised at the fixed temperature before
mixing the enzyme with the substrate.
2. Start the stopwatch immediately after mixing the enzyme with the substrate.
|Temperature(oC)||Time taken for hydrolysis of starch(s)||Rate of reaction (min-1)|
|20||Table Cell||Table Cell|
|30||Table Cell||Table Cell|
|37||Table Cell||Table Cell|
|50||Table Cell||Table Cell|
|60||Table Cell||Table Cell|
Hypothesis is accepted. As the temperature increases, the rate of enzyme reaction on starch increases until the optimum temperature of 37oC.