Enzyme Reaction Rates Using Toothpickase s1

Enzyme Reaction Rates Using “Toothpickase”

1. Your body represents the enzyme TOOTHPICKASE. What type of biological molecule is an enzyme? 2. Your fingers represent what part of the enzyme? 3. What does an unbroken toothpick represent? 4. What do the broken toothpicks represent?

Experiment 1 - Baseline:  Each team of 2 needs a set of 30 flat toothpicks. Decide who will be the enzyme and who will be the timer and data recorder  Set up a data table like the one below in your journal. Time Elapsed: 0 sec 10 sec 30 sec 60 sec 90 sec Number of product molecules  Spread the substrate over about 1/4 the area of your lab station.  The timer will tell the enzyme when to start, and when each interval is up (10, 30, and 60 seconds).  The toothpickase must use only the two fingers on each hand to cleanly break each toothpick, one at a time. - Start breaking toothpicks when the timer says “begin” and placing the products in a pile. - Each time the timer says “time” for a new interval, continue breaking toothpicks, but start a new pile. Keep track of which pile you did when. - When the timer says “stop” at the end of 60 seconds, you must stop.  Work together to count “product molecules”. Place each number in the appropriate space in the data table. Make sure you accumulate toothpick counts. In other words, the 60 sec cell includes all the toothpicks from the 10 sec pile, the 30 sec pile and the 60 sec pile.  Graph your data 5. Why does the line on your graph become “flat” toward the end?

Experiment 2 – Effect of Substrate Concentration  Spread 20 toothpicks as widely as you can across your lab station, the counters behind, and even the floor in your area. This represents a low concentration of the substrate.  The same “toothpickase” should break toothpicks for 30 seconds.  Count, record and graph (same graph) the number of product toothpick ends.  Plot this data on the same graph. Compare to the first trial and explain the difference. 6. Write a sentence comparing what happens when a solution has a low versus high concentration of substrate.

Experiment 3: Effect of ENZYME concentration  Spread out a pile of 20 toothpicks over about ¼ of your station  Double the toothpickase concentration (two people will act as an enzyme in this trial)  Time how many toothpicks are broken in 30 seconds, stopping the clock every 10 seconds to record data. 7. Did you ever run out of substrate? What does this mean? 8. Explain the change of efficiency you observed when enzyme concentration doubled. 9. When did the enzyme concentration have no effect? (Hint: Discuss enzyme concentration vs. substrate concentration)

Experiment 3 – Effect of a Competitive Inhibitor:  To a pile of 20 toothpicks add 10 competitive inhibitors (stout toothpicks or paperclips– they don’t break).  Blindfold “toothpickase”. Enzymes don’t have eyes.  Time the same “Toothpickase enzyme” (team member) breaking toothpicks for 30 seconds. (Pausing every 10 seconds to record data)  You must pick up and “try to” (don’t actually) break each inhibitor as you come to it. Don’t intentionally avoid them (the blindfold solves this problem). You will know not to break it by another partner saying “NO!” when you pick up an inhibitor.  Count and record the total products (broken toothpick ends).  Plot a line for these 30 seconds on the same graph as Experiment 1. 10. How do your results compare with Experiment 1? 11. Why do competitive inhibitors slow the rate that an enzyme can catalyze a reaction?

Experiment 4 – Effect of a partially denatured Enzyme:  Spread out a pile of 20 toothpicks  Toothpickase must cross his/her index finger over the middle finger.  Time the toothpickase enzyme breaking toothpicks (still using index and thumb as the active site) for 30 seconds. (Pause to collect data every 10 seconds)  Plot a line for these 30 seconds on the same graph as Experiment 1. 12. How do your results compare with Experiment 1? 13. Why do competitive inhibitors slow the rate that an enzyme can catalyze a reaction?

Experiment 5: Effect of a fully Denatured Enzyme:  Use masking tape to tape your thumbs to your palms.  Spread 20 toothpicks over a small area at your station.  Time how many toothpicks you can break with just your two index fingers. You may not use any tools or other surrounding surfaces. 14. How does denaturing an enzyme affect its ability to catalyze a reaction?

Experiment 6: Effect of temperature on optimum enzyme activity  Spread out a pile of 20 toothpicks on the table  Soak the toothpickase (your hands) in ice water for 1 minute.  Time the toothpickase enzyme breaking toothpicks for 30 seconds, pausing every 10 seconds to collect data.  Plot a line for these 30 seconds on the same graph as Experiment 1. 15. How do your results compare with Experiment 1? 16. What is the effect of temperature on enzyme activity? 17. What do you predict would happen if the enzyme were to function under extreme heat? Explain.