4.4 Preparatory Questions – Effect of temperature on enzyme activity
1. Aim:
a) State clearly the aim of this experiment.
_________________________________________________________________
_________________________________________________________________
2. Background:
a) What is an enzyme?
_________________________________________________________________
_________________________________________________________________
b) What is the substance an enzyme works on called?
_________________________________________________________________
c) What are enzymes made of?
_________________________________________________________________
d) Where in a cell are enzymes made?
_________________________________________________________________
e) Draw a labelled diagram to explain how an enzyme works.
f) List the factors that affect enzyme activity.
_________________________________________________________________
_________________________________________________________________
g) What is meant by optimum temperature?
_________________________________________________________________
_________________________________________________________________
h) Do all enzymes have the same optimum temperature? Give a reason for your
answer.
_________________________________________________________________
_________________________________________________________________
Biology JH
1
3. Apparatus:
a) Draw a labelled diagram of the apparatus you will use in this experiment.
b) List the solutions you will use in this investigation and explain the purpose of each
solution.
_________________________________________________________________
_________________________________________________________________
_________________________________________________________________
_________________________________________________________________
4. Procedure:
a) What enzyme will you use in this experiment? ____________________________
b) What is the source of this enzyme? _____________________________________
c) What factors will you keep constant during this experiment?
(i)_______________________________________________________________
(ii)_______________________________________________________________
d) How will you keep each factor constant?
(i)_______________________________________________________________
(ii)_______________________________________________________________
e) How will you measure enzyme activity?
_________________________________________________________________
_________________________________________________________________
f) Name the products produced in this experiment.
Biology JH
2
_________________________________________________________________
g) In performing an investigation what is the function of a control?
_________________________________________________________________
_________________________________________________________________
h) Suggest a control for this experiment.
_________________________________________________________________
i) Predict the result of this experiment.
_________________________________________________________________
_________________________________________________________________
j) Name two skills you would expect to learn while carrying out this experiment.
(i)_______________________________________________________________
(ii)_______________________________________________________________
k) State two precautions you should consider before carrying out this experiment.
(i)_______________________________________________________________
(ii)_______________________________________________________________
4.4 Post-experiment questions – Effect of temperature on enzyme
activity
1. (a) Name an enzyme you used during the above experiment. __________________
(b) Name the substrate you used and the product formed. _____________________
____________________________________________________________________
2. What was varied was varied during the experiment? __________________________
How was it varied? ____________________________________________________
____________________________________________________________________
4. Name three factors that were kept constant during the experiment.
(a) __________________ (b) ____________________ (c) _____________________
How were each kept constant?
(a) __________________ (b) ____________________ (c) _____________________
5. What control was used in this experiment? _________________________________
Explain why a control is used.
____________________________________________________________________
____________________________________________________________________
6. How does heat effect the activity of the enzyme?
Biology JH
3
____________________________________________________________________
____________________________________________________________________
7. If the temperature is raised above 60OC, what happens to the active site?
____________________________________________________________________
____________________________________________________________________
8. Give two safety precautions you observed during the experiment.
(i)__________________________________________________________________
(ii) _________________________________________________________________
9. How and why was the pH controlled during the experiment?
How? _______________________________________________________________
Why? _______________________________________________________________
10. How did you measure the rate of the enzyme activity?
____________________________________________________________________
____________________________________________________________________
11. From your results state the optimum temperature for the enzyme you used. _______
12. True of false?
(i) Heat has no effect on an enzyme. ______________________________________
(ii) pH is varied during the above reaction. __________________________________
(iii) Water baths should not be used to vary the temperature. ___________________
(iv) The shape of the graph of rate of enzyme activity v temp is bell shaped. _______
(v) All enzymes are proteins _____________________________________________
(vi) The active site is on the enzyme. ______________________________________
(vii) All enzymes have the same optimum pH but different optimum temperature. ____
(viii) All enzymes have the same optimum temperature but different optimum pH. ___
(ix) All enzymes have different optimum temperatures and different optimum pH. ___
(x) Active sites vary in shape. ___________________________________________
(xi) All enzymes are specific for their substrates. _____________________________
(xii) The optimum temperature for human enzymes is 30OC. ____________________
13. Where are proteins made in the cell? _____________________________________
14. Name the enzyme to match the following substrates and give the product.
Starch:
Enzyme __________________
Product _________________________
Protein: Enzyme ___________________ Product _________________________
Fat / lipid: Enzyme ___________________ Product _________________________
4
Biology JH
H2O2:
Enzyme ___________________ Product _________________________
16. During the above experiment of temp v rate of enzyme activity, the following results
were obtained.
Temp. oC
Rate of reaction ml/min.
(i) Draw a graph for the above data.
(ii) What is the optimum temperature for the enzyme? _________________________
(iii) Estimate, from your graph, the rate of reaction at 26OC. _____________________
(iv) Estimate, from your graph, the temperature that yields a rate of 30ml/min of
product. __________
Biology JH
5