Objective: To simulate the working of enzymes in the catalysis of biochemical reactions. Materials: Bolts (15) and nuts

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Objective:
To simulate the working of enzymes in the catalysis ofbiochemical reactions.
Materials:
Bolts (15) and nuts to match, purchased at a hardware store orfound in your basement. If you don’t have any nuts and bolts, useanything made of two parts that can be taken apart. For example,red and blue paper clips, large and small paper clips, baby foodjars and lids. Use your imagination. In addition, you will needsomething to glue the two pieces together. You will also need adevice to time yourself, a watch with a second hand or astopwatch.
Background Information and Theory:
Read about Enzymes in unit 10. Most of the metabolic reactionsin Units 13 and 14 are catalyzed by enzymes. Enzymes work bylowering the activation energy for biochemical reactions. The firststep is for the substrate (S), the reactant to react with theenzyme (E) to form the Enzyme-Substrate Complex (ES):
E + S ES. The second step is for the enzyme to convert thesubstrate into the product(s). In this case there will be twoproducts, P1 and P2: ES P1 + P2. In this simulation the substratewill be the nut and bolt screwed together. You will be the enzyme.As the enzyme, it will be your job to find the substrate andunscrew the nut from the bolt. The nut will be P1 and the bolt willbe P2. The simulation will simulate the case where the substrateconcentration is less than saturation, below maximum velocity). Itwill also simulate saturating the substrate concentration, atmaximum velocity). Competitive Inhibition, and non-competitiveinhibition will be simulated as well.
Procedure:
Enzyme Kinetics When Substrate Concentration is LessThan Saturation
Screw the 15 nuts on to the 15 bolts. Scatter the bolts randomlyaround the room you are in. Start the timer and gather and unscrewas many nuts as possible in 30 seconds. Record the number of boltsunscrewed on the table/report sheet table following theseinstructions Divide the number of bolts unscrewed by the time (0.5minutes) to get the rate of the reaction.
Enzyme Kinetics When Substrate is atSaturation
Reattach the 15 nuts to the bolts. Put all the nut/boltcombinations in front of you on the table. Start the timer andunscrew as many nuts as possible in 30 seconds. Record the numberof bolts unscrewed on the report sheet. Divide the number of boltsunscrewed by the time (0.5 minutes) to get the reaction rate.
Enzyme Kinetics With Competitive Inhibition
Reattach the nuts to the bolts. Glue 10 of the nuts to thebolts, so they can’t be removed. Place the nut/bolt combinations ina pile. Unscrew as many of the nuts as possible in 30 seconds.Count the number of unscrewed nuts. Don’t try to muscle the gluedones. They can’t be removed. Count the number of nuts unscrewed.Record this number in the table. Also record the reaction rate bydividing by the time (0.5 minutes)
Enzyme Kinetics With Non-CompetitiveInhibition
Reattach the nuts to the bolts. Place the nut/bolt combinationsin front of you on the table. Have someone tie your hands behindyour back, or mentally tie your hands behind your back. Start thetimer and see how many nuts you can remove from the bolts. Recordthe numbers of nuts that are removed. Divide by time (0.5 minutes)to get the reaction rate.
Questions and Conclusions
Answer the questions below the data table. In a paragraph,describe what you have learned about enzyme kinetics from thisexperiment. Save the report sheet as a WORD document and submit itas an attachment for the Unit 14 lab.
Data Table and Report Form for Enzyme KineticsSimulation Experiment
Name_______________Date______________________
Condition
Number of Bolts Unscrewed
Time (minutes)
Reaction rate (bolts per minute)
Comment
Scattered bolts
11
0.5
22
Non-saturated substrate
Pile of Bolts
15
0.5
30
Saturated Substrate
Some Bolts Glued
3
0.5
6
Competitive Inhibiter
Arms tied
0
0.5
0
Non-Competitive Inhibitor
Questions:
1. Under which condition was the rate the fastest. Why wasit fastest?
2. Under which conditions was the rate slowest? Why was itthe slowest?
3. Considering the scattered bolt experiment, how would therate change if you scattered the bolts all around your yard ratherthan just in your room? Because the volume is increased, theconcentration decreases.
4. Below the saturation point, how does the rate of anenzyme-catalyzed reaction change with concentration?
5. When the bolts are in a pile, does this represent asmaller or greater concentration than when they are scattered.
6. Is it possible to get a greater substrate concentrationthan in the pile?
7. What would happen to the rate if the enzymeconcentration were increased in the scattered bolt experiment? (Forexample, if you had a buddy help unscrew the nuts.)
8. In the scattered bolt experiment how would the rate ofreaction change if you ran around the room faster picking up bolts?(This would be similar to increasing the temperature.)
9. What would happen to the reaction rate, if you ranaround the room so fast that you collapsed from exhaustion beforethe time was up?
10. How is the situation in 9 similar to the effect oftemperature on reaction rate?
11. How would the rate of reaction change if fewer nutswere glued to the bolts in the third experiment?
12. How would decreasing the competitive inhibitorconcentration change the rate of an enzyme-catalyzed reaction?
13. How would the rate of the non-competitive inhibitorreaction change if several people held your arms behind yourback?
14. How would the rate of the non-competitive inhibitorexperiment change if the concentration of the inhibitor wereincreased?
Conclusion
How well do you think this simulation represents enzymekinetics? Did it help you understand kinetics better? Can you thinkof anything that could be added to improve the simulation?