biology - enzyme lab conclusion

7/22/2019 Biology - Enzyme Lab Conclusion

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Lani Chung

Mr. Nakamura

Biology

21 September 2011

Enzyme Lab Conclusion

The first part of the experiment involved adding 5 drops, 10 drops, and 20 drops of

enzymes to three different test tubes respectively with 5mL of 3.0% H2O2and 5mL of water each

in order to test the effect of enzyme concentration on enzyme activity. Our results which were

the rates of each testcame out to 0.01821% per minute for 5 drops, 0.01677% per minute for 10

drops, and 0.01222% per minute for 20 drops. We also found the rates of each test in minute

time intervals. For 5 drops of enzymes we had 0.001636%/min. for 0-0.5 minutes,

0.008096%/min. for 0.5-1.0 minutes, 0.01292%/min. for 1.0-1.5 minutes, 0.02267%/min. for

1.5-2.0 minutes, and 0.01818%/min. for 2.0-3.0 minutes. For 10 drops of enzymes we had

0.01853%/min. for 0-0.5 minutes, 0.02166%/min. for 0.5-1.0 minutes, 0.02312%/min. for 1.0-

1.5 minutes, 0.02486%/min. for 1.5-2.0 minutes, and 0.01892%/min. for 2.0-3.0 minutes. For 20

drops of enzymes we had 0.1214%/min. for 1-1.5 minutes, 0.07399%/min. for 0.5-1.0 minutes,

0.03824%/min. for 1.0-1.5 minutes, 0.03524%/min. for 1.5-2.0 minutes, and 0.02828%/min. for

2.0-3.0 minutes. For the second part of our experiment we filled 3 test tubes with 3mL of 3.0%

H2O2and 3mL of water each and placed them in a water bath of 400mL beaker filled with ice

and water in order to test the effect of temperature on enzyme activity. To each test tube we

added 10 drops of enzymes and recorded the average temperature (which was 0.3 C) as well as

the rate of activity. We had 0.0074%/min. for the first trial, 0.0122%/min. for the second trial,

0.0081%/min. for the third trial, and 0.00923%/min. as an average of the three trials. The other

groups in the class also conducted similar experiments but with different temperature water baths:

3groups had the 0-5 water bath, 3 groups had the 20-25 water bath, and 2 groups had the 40-45


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water bath. The results of the class data are as follows: 3 had an average rate of 0.00923%/min,

2 had 0.01047%/min, 2 had 0.00816%/min, 45 had 0.00456%/min, 45 had 0.00808%/min,

42 h ad 0.00839%/min, 26.7 had 0.00882%/min, and 26.4 had 0.01057%/min.

For the enzyme concentration portion of the experiment, the rate of enzyme reactions got

progressively lower as more drops of enzymes were added. Although normally you would expect

the reaction rate to increase with a higher enzyme concentration since if there is more of a

substance there is a greater chance that molecules will collide and speed up the rate of the

reaction, our results showed the opposite. This could have resulted from a very quick rate of

increase and a rapid decline after all the hydrogen peroxide was catalyzed by the high enzyme

concentration. The data in the time interval enzyme concentration table can help justify this

claim as you can see that for the 20 drop test, the first 30 seconds had the highest rate of enzyme

activity while the next intervals up to 3 minutes showed steep declines in activity. However in

the 5 drop and 10 drop tests, there was a gradual increase until the last interval where there was a

slight decline in reaction rate. This means that although the enzyme concentration had its

predicted effect of increasing the chances of enzyme-substrate collision, the reactions just

happened so quickly that they happened in the first few intervals and declined all the way to the

end of the set time period. Because the data is measured in overall rate for the entire 420 seconds,

the results may be misleading as the higher enzyme concentration experiments would peak very

early and continuously decline. This relates to the purpose of the experiment because it allowed

us to see that enzyme concentration helped had the effect of increasing the reaction rate. For the

enzyme temperature portion of the experiment we found that the average rate of enzyme activity

was a lot lower than the 10 drop enzyme concentration experiment done in the previous portion

of the experiment. This suggests that lower temperatures caused a slower enzyme reaction rate


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collect data. Other than these few mistakes and problems, our entire experiment went pretty well

as a whole.

If I had to repeat the entire experiment over again, there isnt a lot that I would have done

differently. The only big change I would have made would have been to put the test tubes into

the cold bath one by one instead of all at once. Changing up this part of the experiment would

probably help ensure better data accuracy. Another change could have been to measure enzyme

activity through different methods such as the pressure of the produce (oxygen) as it appears and

the rate of disappearance of the substrate (the hydrogen peroxide) to help make better

comparisons and come up with a better analysis.

biology - enzyme lab conclusion

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