4.4 (a) To investigate the effect of temperature on the rate of
amylase activity
Teacher Notes
Apparatus required per class group of 24 students
Enzyme source eg. amylase
Starch
Buffer solution pH 7
Boiling tubes
60
Water baths
4
Thermometers
4
Droppers
12
Boiling-tube holder
12
Disposable gloves
Timer
12
Boiling tube rack
12
The apparatus for this experiment lends itself to being pre-prepared in a ‘box of
equipment’ – see Section 1.
Advance preparation
o Prepare solutions
Advance chemical preparation
(a) Starch solution:
o Shake 1 g of soluble starch (Analar) on to100 ml of water and bring to boiling point to
obtain a clear solution. Cool.
o Make up to100 ml with water.
o Starch solution should be freshly prepared every time it is used.
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(b) Amylase solution
o Add 1g of amylase solution to a little distilled water.
o Make up to 100 ml with distilled water.
Safety precautions
o See MSDS for further information.
Expected outcome of experiment
o The enzyme, Amylase, works best at 37oC
Disposal and post-experiment work
o Amylase – mix solids with excess sand (100 g:5 L) and put in refuse. Flush solutions
with excess water to foul drain
o Buffers – dissolve small quantities (50 g) in 5 L of water and flush to foul drain
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4.4 (a) To investigate the effect of temperature on the rate of
amylase activity
Student Notes
Apparatus required per group
o Amylase solution
o Starch solution
o Buffer solution, pH 7
o 6 x Boiling tubes
o 1 x Dropper
o 1 x Timer
o 1 x Boiling tube holder
o 1 x Boiling tube rack
o Disposable gloves
Assembled apparatus
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Method
1. Set up 5 water baths at different temperatures e.g. 0OC, 20OC, 35OC, 55OC,
80OC.
2. Into each of 5 boiling tubes put 5 ml of starch and 3 drops of iodine (each turns
blue/black).
3. Into each of 5 more boiling tubes put 2 ml of amylase solution.
4. Place a pair of boiling tubes (one starch and one amylase) into each water bath
and leave for 5 minutes.
5. Pour the amylase into the starch/iodine tube. Gently shake each tube to mix the
contents.
6. Replace the tube in the water bath and measure the time taken for the solution to
go colourless ( the blue/black colour should fade as the amylase changes the
starch into sugar).
7. Test for sugar by adding Benedict’s solution and heat for 5 minutes – a brick red
brick colour indicates the presence of sugar.
8. Graph your results.
9. Repeat the above experiment with boiled amylase – this will act as the control.
10. At the end of the experiment, clean all of the equipment and replace it in its
correct place.
Results:
Temperature (OC)
Time taken for solution to
turn colourless
Test for sugar
Conclusion/Comment
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