Biology Essay Research Paper Investigation on factors

Biology Essay, Research Paper

Investigation on factors affecting the enzyme Amylase

Aim: An investigation into the factors affecting the activity of the enzyme Amylase – Planning

Prediction:

I predict that as the temperature increases, the speed of the reaction will increase. When a particular temperature is reached, I believe the rate of reaction will dramatically decrease. I believe this because most chemical reaction happens faster when the temperature is higher. At higher temperatures molecules mover around faster, which makes it easier for them to react together. Usually, a rise of 10 degrees celius will double the rate of reaction. This is true for enzymes up to about 40 degrees celius. However at 40 degrees celius the enzyme begins to be damaged, so the reaction slows. By 60 degrees celius, the enzyme is completely denatured. I predict that the same will happen the further away the pH is from pH 7. I believe this because the optimum temperature for most enzymes is about pH 7 therefore the further away from pH 7 (either more alkaline or more acidic) the less affective the enzyme.

Pilot Experiment:

To investigate the factors affecting the activity of the enzyme Amylase, I will adapt a pilot experiment, which investigates if the enzyme amylase breaks down starch. The pilot experiment was:

1. Pour amylase solution into a test tube to a depth of 2cm.

2. Half fill another test tube with a 4% starch solution.

3. With a pipette, place a drop of iodine into each dimple in a dimple tray.

4. With a glass rod lift a drop of the starch solution from the test tube and mix it with the first drop of iodine in the first dimple in the tray. A blue/black colour should develop; this will be used as the control.

5. Rinse the glass rod.

6. Pour amylase solution into the test tube of starch and shake quickly.

7. Repeat steps 4 & 5 (for the amylase & starch solution mixture) every 30 seconds until a blue/black colour no longer develops.

8. When there is no further change in the colour of the iodine, take the starch-amylase test tube, add Benedict s reagent, and place in the water bath for 1 minute.

Adapted Experiment:

I will modify and expand the pilot experiment in a number of ways. Firstly, I must decide what I am going to investigate. I am going to investigate the effect of pH and temperature on the activity of the enzyme amylase. Therefore, I have developed two similar experiments (one for each factor I am investigating).

To investigate the effect of pH on the activity of the enzyme amylase:

1. Pour amylase solution into a test tube to a depth of 2cm.

2. Half fill another test tube with a 4% starch solution.

3. With a pipette, place a drop of iodine into each dimple in a dimple tray.

4. With a glass rod lift a drop of the starch solution from the test tube and mix it with the first drop of iodine in the first dimple in the tray. A blue/black colour should develop; this will be used as the control.

5. Rinse the glass rod.

6. Add 2cm3 of the appropriate pH buffer to the starch solution and shake.

7. Pour amylase solution into the test tube of starch and shake quickly.

8. Repeat steps 4 & 5 (for the amylase, starch & pH buffer mixture) every 30 seconds until a blue/black colour no longer develops.

9. Record the results in a table. Repeat steps 1-8 for each pH buffer range until all the provided pH buffers have been used.

Temperature: To investigate the effect of temperature on the activity of the enzyme amylase:

1. Pour amylase solution into a test tube to a depth of 2cm.

2. Half fill another test tube with a 4% starch solution.

3. Cool both test tubes and maintain at 10 degrees celius

4. With a pipette, place a drop of iodine into each dimple in a dimple tray.

5. With a glass rod lift a drop of the starch solution from the test tube and mix it with the first drop of iodine in the first dimple in the tray. A blue/black colour should develop; this will be used as the control.

6. Rinse the glass rod.

7. Add 2cm3 of water to starch solution (see below).

8. Pour amylase solution into the test tube of starch and shake quickly (measure temperature, try to maintain at 10 degrees celius).

9. Repeat steps 4 & 5 (for the amylase & starch solution mixture) every 30 seconds until a blue/black colour no longer develops.

10. Record the results in a table. Repeat steps 1-9 increasing the temperature by 5 degrees celius each time until the enzyme is denatured, this should be around 40 degrees celius (see part 6 on enzymes.)

To ensure that the test is fair I will only vary two factors (at different stages of the experiment not simultaneously). All the quantities will have to be carefully measured since small variations in the amount of enzyme used can make significant variations in the results. In the section where temperature is investigated, 2cm3 of water is added. This is because the starch solution is neutral and in the previous investigation (for pH) 2cm3 of the appropriate buffer was added. If the 2cm3 of water was not added then it would not be a fair test since the volumes used in each part of the investigation would be di

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