Revision questions on enzymes
1. Enzymes _______ up the rate of chemical ________.
2. Enzymes are ________ because they only work on one
substrate.
3. The substrate fits into the ________ site of the
surface of the _______.
4. With an increase in ________________ the rate of
reaction _________.
5. Enzymes can be re-used, so only _______ amounts are
needed.
6. To which group of chemical compounds do enzymes
belong? _________
7. Why is an enzyme specific for a particular substrate?
_________________________________________
8. Why can an enzyme be used again and again?
_________________________________________
9. Slide 10 of the power point shows 2 enzymes. Which
enzyme works best in acidic conditions? __________
Which works best in alkaline conditions? _________
What does the graph tell you about the range of pH over
which each enzyme is active?
10. A number of factors can alter the rate of an enzymecontrolled reaction. Say what each of the following would
do to the rate of reaction and give your reasons.
An increase in enzyme concentration
___________________________________________
___________________________________________
A decrease in temperature
___________________________________________
___________________________________________
A lowering of pH
___________________________________________
___________________________________________
11. Lipase is an enzyme that breaks down fats. We can use an
indicator to follow this reaction. The indicator is red to
start with but turns yellow when all the fat has been
broken down. Look at the results table below.
Test-tube
Temp (oC)
Original colour
Final colour
1
0
Red
Red
2
10
Red
Orange
3
40
Red
Yellow
4
60
Red
Orange
5
100
Red
Red
What is the optimum temperature for lipase? ________
Why do you think the colour didn’t change in test tube 1?
___________________________________________
Why do you think the colour didn’t change in test tube 5?
___________________________________________
Predict what you think would happen if you warmed test
tubes 1 and 5 up to 40 oC. Try to explain your prediction.
___________________________________________
___________________________________________
___________________________________________
12. Which enzymes work on carbohydrates? ____________
13. Which enzymes work on proteins? _________________
14. Which enzymes work on fats? ____________________
15. Name the products which are formed in each case.
___________________________________________
___________________________________________
___________________________________________
16. Name 3 functions of bile
___________________________________________
___________________________________________
___________________________________________
17. In 1989 a new fat digesting enzyme was found in a
fungus. It’s optimum pH is 7.5. It can act at low
temperatures and after a few days, breaks down into
carbon dioxide, nitrogen and water. Give 2 reasons why
this enzyme is now used in washing powder
___________________________________________
___________________________________________
Why would a washing powder of high pH or low pH be
difficult to handle?
_____________________________________________
_____________________________________________