Investigate the effect of changing the temperature of amalayse on the breakdown of starch to glucose.

 

                                                                     

                                                          ACTIVE SITE

                                                           

                         

                                 

The substance on which the enzyme works is called the subtrate, in this case, starch particles.

The enzyme I am going to use in my experiment is amalyse. This is found in saliva and catalyses the breakdown of starch to glucose, which is exactly ehat I need for this experiment.

To help me plan for my investigation, idid some preliminary work using a computer program called ‘Science Investigation One’. This is what my preliminary work told me:

 

 

 

Apparatus:

• Test tube
• Measuring cylinder
• Dimple tray
• Two pipettes
• Iodine
• Starch solution
• Amalayse
• Water bath
• Supply of hot water (kettle)
• Ice cubes
• Thermometer
• Stopwatch
• Stirring rod

Method:

1. Put 5cm  of starch solution into a test tube, using a measuring cylinder.
2. Add 5cm  of amalayse solution and mix with a stirring rod.
3. Get the solution to 10 c by putting the test tube in a water bath at 10 c. Put ice cubes in the water bath to bring the temperature down.
4. Check the temperature with a thermometer. Once it is 10 c leave it for one minute.
5. Using a pipette, remove a sample from the test tube and put one drop into the dimple tray.
6. Add one drop of iodine to the sample.
7. If the sample goes brown, move onto the next temp.
8. If the sample goes blue/black, repeat steps 5 & 6 every minute until the sample stays brown.
9. Repeat at temperatures 20 c, 30 c, 40 c, 50 c & 60 c.

10.Use a water bath and a kettle to get the solution to  

    each temperature.

Fair test table:

Results:

Average:

Conclusion:

As the temperature got higher, the time taken for the starch to break down got faster, until it past the optimum and denatured. To start off the starch particles have no energy at 10 c, but as the temperature increases, the breakdown gets quicker because the particles have more energy. This theory works because the particles dissolve quicker when they collide, and collide more when they have the most energy to move around. When the amalayse reaches the optimum temperature of around 50 c it starts to denature, so the starch takes longer to break down, until eventually it denatures fully and doesn’t breakdown the starch at all. I think this conclusion matches up pretty well with my prediction.

Evaluation:

 This was a fair test because I used the same amount of starch, amalayse and iodine in every test and at every temperature. I also made sure I took each sample exactly on the minute. I think my experiment went quite well and although each of my three readings show a different pattern, they all seem to have more or less the same difference of time between each temperature so there are not any odd or stray results. They are all pretty accurate.

I think one way I could improve my method is to lay out the dimple trays and put iodine in each one ready. That way I wouldn’t have to worry about adding the iodine between each sample, leaving me more time to concentrate on my observations. But otherwise I found the method easy to follow and quite organised. I was happy with my results because they support my prediction and conclusion because the readings went gradually up until it stopped because the amalayse denatured and this worked with all three readings.