The aim of this investigation is to find out and prove the temperature in which the enzyme amylase works best at.

                                                         

 

    

I predict that as the temperature increases, the starch will get broken into glucose; and when tested with iodine, the solution will stay the same colour due to the sugar being formed and the reaction taking place quicker

with more heat. On the other hand, when the temperature of the water is above 40°  (after the body temperature) the amylase will stop breaking the

starch down, due to the high temperature denaturing the amylase molecules that will not fit into the starch molecules, and therefore, turning the solution into a blue/black colour when tested with iodine.

        

Apparatus:

• 10ml measuring cylinder

• Thermometer
• Stop clock
• Iodine solution
• Starch
• Amylase
• Spotting tile
• Two pipettes
• Two test tubes
• Goggles
• Water at 20°, 30°, 40° and 50°. 

Diagram:

 

Method:

First of all, I will make sure my goggles are on at all times throughout the experiment. In order to carry out the experiment, firstly collect the equipment listed above. Then, set it up as shown in the above diagram. I will add 5ml of starch into the amylase solution and also start the stop clock when doing this. I will take a drop out of the test tube, using a pipette and put it into the dropping tile. Every 30 minutes, until 180

seconds. I will record my results in the table shown below; by putting either a tick or a cross in the table. I will repeat the experiment 4 more times, with the following temperatures of water: 30°, 40°, 50°, and 60° (because this is the control of the experiment), recording my results as I go along.

Fair test

In order to make my experiment a fair one, I will have to keep the following factors constant:

• The amount of starch (10ml)
• Amount of amylase (5ml)
• Time for recording

Accuracy:

In order for my experiment to be an accurate one, I will make sure that I measure everything correctly, using a small cylinder. When measuring the solutions, I will make sure that I measure the solution from the meniscus, so that it is accurate.

Reliability:

In order for my experiment to be a reliable one, I will make sure that I repeat the experiment 2 times; by doing this, I will be able to spot any anomalous results immediately.

Results:

1st reading:

2nd reading:

3rd reading:

Conclusion:

I found out that the temperature of the water does affect the rate of reaction. My prediction was correct. From my readings, I found out that the enzyme amylase does work best at 40° because this is the closest temperature to 37° (body temperature). I found that my amylase sometimes reacted with the starch to make glucose at 50°. This was probably because the water had cooled down by the time I got to do the experiment; and therefore, the starch reacted with amylase at a temperature less than 50°.

To make this experiment more accurate, I will have to make sure that the temperature stays the same throughout the experiment, so that I have more accurate results.

Evaluation:

If I had to study this practical again, I could change the temperature of the amylase or the starch and study how this affects the rate of reaction.

In my results, I would note down the colour of the solution when tested with iodine so that I can analyse how much starch has been broken down yet. I would be able to tell by the lightness/darkness of the colour of the solution.