Human Physiology ISA – ISA 1 Amylase Action

Enzyme Reactions

Variables

• Independent– Temperature

• Dependent – Time it takes to digest starch

• Control Variables– Volume of starch/iodine/water/amylase– Concentration of starch/amylase

Apparatus

• 1% amylase• 0.5% starch• Strong iodine • Thermometers• Spotting tiles• Tin foil• Pipettes

Investigation- Independent Variable – Temperature. Dependent Variable- time

taken for starch to digest1. To one test tube add 4cm3 of starch solution2. To another test tubes add 1cm3 of amylase3. Set up a water bath to your required temperature

(20,30,40,50,60)4. Place both test tubes in the water bath for 5 minutes.5. During the 5 minutes set up a white tile with a drop of

iodine in each well – each well represents 30 seconds.6. After 5 minutes pour the starch in to the amylase test

tube.7. Start timing8. Take a small sample and place in the first well9. Place back in the water bath10. Take a sample from the test tube every 30 seconds and

add to an iodine drop in the well.11. Continue until the colour no longer changes12. Repeat for different temperatures

e

Results – Plot a graph

Temperature © Time taken to digest starch (s)

20 210

25 150

30 90

35 30

40 30

45 180

50 330

55 600

Investigation

• What was the Control Investigation and why?

• Reliability

• Conclusion – include figures

Design an Investigation

• Think about variables• Think about what you are changing –

the temperature• Think about what you need to keep

the same• Think about how you will know which

one has worked• Think about repeats