1. Required practical 5 Investigate the effect of pH on the rate of reaction of amylase

3. Syllabus

4. 5
1.Hypothesis
2. Equipment list
3. Method
4. Results table
5. Graph
6. Conclusion
7. Evaluation

6. Class Results (pool data – do not copy)
pH of solution
Time taken for amylase to completely break down the starch in minutes (m)
Rate of reaction
(m-1) 2 4 5 6 7 9
You can wash out the dimple tile and keep going if it fills up

7. Questions 1. What were the independent and dependent variables?
2. Name as many things kept constant (controlled) in the experiment as you can.
3. What was the optimum pH for amylase?
4. Is this what you expected for optimum pH?
5. The enzyme used in the experiment was from a fungus. Does this change your opinion of the optimum pH?
Annotate onto your graph why the reaction is slower at pH lower than and higher than the optimum pH.
The best answers will include a diagram of the shape of the active site in 3 places on your work.(WS2.1)
7. Evaluation – what could you improve in this investigation? Try to give at least 3 things. (WS 2.5)

8. 10T Class Results
pH of solution
Time taken for amylase to completely break down the starch in minutes (m)
Rate of reaction
(m-1) 2
Black after 10 mins = 0 4
1.5
0.66 5
0.5 6 7
2.5
0.4 9
You can wash out the dimple tile and keep going if it fills up

9. 10W Class Results
pH of solution
Time taken for amylase to completely break down the starch in minutes (min)
Rate of reaction
(min-1) 2
Black after 10 mins = 0 4 1 5
0.5 6 7
3.5
0.29 9
You can wash out the dimple tile and keep going if it fills up

10. What is missing?

11. Questions 1. What were the independent and dependent variables?
2. Name as many things kept constant (controlled) in the experiment as you can.
3. What was the optimum pH for amylase?
4. Is this what you expected for optimum pH?
5. The enzyme used in the experiment was from a fungus. Does this change your opinion of the optimum pH?
Annotate onto your graph why the reaction is slower at pH lower than and higher than the optimum pH.
The best answers will include a diagram of the shape of the active site in 3 places on your work.(WS2.1)
7. Evaluation – what could you improve in this investigation? Try to give at least 3 things. (WS 2.5)

12. Risk assessment All solutions, once made up, are low hazard.
Refer to Hazcard 33 for amylase.
Iodine solution may irritate the eyes so safety goggles should be worn. Refer to Hazcards 54A and 54B.
Universal buffer solution is an irritant. Refer to Hazcards 9, 14, 72, and 91.
Safety goggles should be worn in the presence of hot water in water baths.
Care should be taken with the use of naked flames in this experiment if students are using Bunsen burners to make water baths.
Care should be taken with the presence of water and electrical equipment, if electrical water baths are being used.
Note that some people are allergic to enzymes.

16. Keywords
Amylase Carbohydrase Starch Iodine solution Continuous sampling technique