Required practical: Investigating the effect of ph on the rate of reaction of amylase enzyme

Question 1

Method

Answer 1

1) Put on safety glesses.
2) Collect equipment, label 3 test tubes(Starch, Amylase and (specific value) ph).
2) Add 2cm3 of starch solution to the test-tube labelled starch.
4) Add 2cm3 of your specific PH to the test tube labelled PH.
5) Place all of these labelled test tubes with solutions into the water bath(beaker of water from main water bath) and wait until solutions have reached 35C.
6)Put one drop of iodine to each depression/spot on the tile.
7) When the tubes have reached 35C, add the ph contents to the starch test-tube and stir. Then add this to the amylase test tube. Your PH test tube should now contain 2cm3 starch, 2cm3 amylase and 2cm3pH.
8)Start the timer immediately and stir this solution.
9) Use a pipette to remove a few drops of solution every 10 seconds from the test tube, put them in a different well of the spotting tile.
10) The iodine should turn a blue-black colour, repeat until the iodine solution stops turning black(is yellow/orange), which means all of the starch is broken down by amylase.

Question 2

Equipment

Answer 2

10 test tubes
A test tube rack
A water bath
A thermometer
A spotting tile
A 5cm3 measuring cylinder
Pasteur pipettes
A glass rod
A stop clock
Starch solution
Amylase solution
Iodine solution
Labelled buffered solutions at a range of PH values

Question 3

Control variables

Answer 3

Volume of starch
Volume of amylase solution
Volume of PH solution

Question 4

What is used to measure the ph of the solution in the boiling tube

Answer 4

A Ph Meter/indicator paper so it doesn’t interfere with the reaction/change the colour of the solution

Question 5

Why is using a stopwatch more accurate than using a wrist watch?

Answer 5

A stopwatch has a greater resolution than a wrist watch.