Toothpickase

In this activity you will simulate enzyme function in response to a variety of changes. Your fingers are the enzyme toothpickase, which breaks toothpicks in half. The enzyme substrate is a toothpick. To perform the reaction, place a toothpick between the thumb and forefinger of both hands and break it in half. Always break the toothpicks one at a time.

1. Select ten toothpicks and spread them out on a desk. Do not line them up.

2. With one partner timing, determine how long it takes to break the ten toothpicks as fast as possible.

3. Calculate the rate of enzyme activity in toothpicks per second.

4. Select twenty new toothpicks and spread them out on a desk. Do not line them up.

5. With one partner timing, determine how long it takes to break the twenty toothpicks as fast as possible.

6. Calculate the rate of enzyme activity in toothpicks per second.

7. Select ten new toothpicks and spread them out randomly on a desk. Do not line them up.

8. This time both partners will break splints. Measure the time required for both partners to break the toothpicks simultaneously.

9. Calculate the rate of enzyme activity in toothpicks per second.

10. If time permits, put on the heat-resistant gloves.

11. Select ten new toothpicks and spread them out on a desk. Do not line them up.

12. Determine how long it takes to break ten toothpicks as fast as possible.

13. Calculate the rate of enzyme activity in toothpicks per second.

Questions

a) Under what conditions did the fastest reaction rate occur?

b) What is each part of this activity meant to model?

c) How could the procedure be modified to simulate an experiment showing the effect of

            i) competitive inhibitor

            ii) noncompetitive inhibition

            iii) change in pH

            iv) change in temperature

            v) non-reversible inhibitor