Enzyme Activity Ia

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  • Topic: Enzyme, Test tube, Fat
  • Pages : 6 (1524 words )
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  • Published : June 11, 2011
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Year 11 IB Biology IA Report
2011

5/31/2011

Enzyme Activity Experiment
Introduction3
AIM3
Materials3
Method4
Result5
Table 1:5
Table 2:5
Graph 16
Discussion6
Conclusion8
Bibliography9
Appendix 1 (Test tube 3- 45 degrees)9
Appendix 2 (Test tube 1- 5 degrees)9
Appendix 3 (Test tube 2- 20 degrees)9

Introduction

Phenolphthalein is an indicator that is pink in alkaline solutions of about pH10. When the pH drops below pH 8.3 phenolphthalein will go colourless. Here, an alkaline solution of milk, lipase and phenolphthalein will change from pink to colourless as the fat in milk is broken down to form fatty acids (and glycerol) thus reducing the pH to below 8.3. The time taken for this reaction to occur is affected by temperature. AIM

To investigate the effects of increasing temperature on the activity of enzyme Lipase. Materials
* Milk, full-fat or semi-skimmed, 5 cm3 per student per temperature assessed * Phenolphthalein in a dropper bottle (see note 1)
* 5% lipase solution, 1 cm3 per student per temperature assessed * Sodium carbonate solution, 0.05 mol dm-3, 7 cm3 per student per temperature assessed * Electric hot water baths set to a range of temperatures, each containing a thermometer, a test-tube rack and a beaker of lipase solution. * Ice

* Marker pen
* Test tube rack
* Measuring cylinder (or syringe), 10 cm3, 2
* Beaker, 100 cm3, 2 (for milk and sodium carbonate solution) * Beaker, 250 cm3, 2 (to act as water baths for temperatures below room temperature) * Thermometer
* Test tube
* Glass rod
* Syringe, 2 cm3
* Stop clock/stopwatch
Method
1. Label a test tube with the temperature to be investigated. 2. Add 5 drops of phenolphthalein to the test tube.
3. Measure out 5 cm3 of milk using a measuring cylinder (or syringe) and add this to the test tube. 4. Measure out 7 cm3 of sodium carbonate solution using another measuring cylinder (or syringe) and add this to the test tube. The solution should be pink. 5. Place a thermometer in the test tube. Take care as the equipment could topple over. 6. Place the test tube in a water bath and leave until the contents reach the same temperature as the water bath. 7. Remove the thermometer from the test tube and replace it with a glass rod. 8. Use the 2 cm3 syringe to measure out 1 cm3 of lipase from the beaker in the water bath for the temperature you are investigating. 9. Add the lipase to the test tube and start the stopclock/ stopwatch. 10. Stir the contents of the test tube until the solution loses its pink colour. 11. Stop the clock/ watch and note the time in a suitable table of results.

Result
Table 1:
| Test tube 1 5 degrees| Test tube 220 degrees| Test tube 345 degrees| Test tube 465 degrees| Time (min: sec: usec)| 31:04:86 ()| 16:26:17| 2:09:03| 32:20:74 ()| Notes| The test tube was breakdown before the liquid (milk) turns white| Complete| Complete| The liquid didn’t turn white, and colour of the liquid (Milk) was light pink| Table 2:

Time (Min)| Test Tube 15 degrees| Test tube 220 degrees| Test tube 345 degrees| Test tube 465 degrees| 00:00:00| | | Light pink| |
02:00:00| | Pink | Completed| |
04:00:00| | | | Turn light pink|
06:00:00| | Light pink| | |
08:00:00| Turned light pink| | | |
10:00:00| | | | lighter|
12:00:00| | White with Pink| | |
14:00:00| Lighter| | | White with pink|
16:00:00| | Completed| | |
18:00:00| | | | |
20:00:00| | | | |
22:00:00| | | | |
24:00:00| | | | |
26:00:00| Really Light pink| | | |
28:00:00| White with pink| | | |
30:00:00| | | | |
Graph 1
Discussion
As the introduction of this report shown that the phenolphthalein is an indicator that is pink solution of about pH10, and when the pH drops below pH8.3 phenolphthalein goes colourless. Through this...
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