Amylase vs Starch vs Temp vs Buffers Lab Report Essay
“Effects of Amylase reaction time when breaking down starch. ” Experiment Goal: The goal of our experiment was to understand the similarities in digestion by finding out how long it takes for the amylase enzyme, found in saliva, to break down our substrate, starch. Hypothesis: While understanding that starch is broken down by our saliva (amylase enzyme) we predict that the higher the concentration of the enzyme the faster the breakdown of the starch. Materials: Brightly colored test tube rack, kim wipes, beaker for trash 1.
5 ml microcentrifuge tubes
Test plate Micropipetters and tips DI water Buffer solution … 4. 5 to 8. 8 I2Kl (grams iodine) Starch solution Enzyme (amylase) 80 degree Celsius water (HOT) Floating test rack Procedure: While controlling the amount of starch and the amount of buffer we use with a pH of 5. 8, we want to investigate how changes in enzyme concentration affect reaction rates. First we put 500 ml of amylase from 0. 2% solution (provided by Michael Bunch) into an experimental tube. We then put 3 drops of Iodine into a test plate (the color is brown).
While ready to time our reaction, we added 250 ml of starch solution into the mixture of buffer and amylase. The reaction had started instantly. We first timed the reaction at 20 seconds. At 20 seconds, we removed a 25 ml sample of the mixture and dropped it into one of the test sights of iodine. The color of the brown iodine turned immediately purple. Traces of purple in the iodine and amylase mixture indicate that the amylase did not have enough time to break down the starch completely. We tried this pattern of every 20 seconds for up to three minutes.
The amylase was not breaking down the starch. Because no reaction after too much time, we increased the amylase solution to 0. 5% and started our experiment over. After resetting our experiment back up we then made our solution of amylase and starch and started our timing intervals at 10 seconds. The color of the iodine was brown after only 10 seconds. This indicated that upping the amylase concentration to 0. 5% made the reaction faster, but not too fast. Since the reaction was too fast for complete observation we diluted the 0. 5% solution so that it could slow down the reaction time.
We tried a 200/800 enzyme to buffer or 0. 1% of the 0. 5% solution. After mixing the solution and timing again we discovered that 10 seconds was still too fast and that the iodine was again brown. With another diluting solution in mind we diluted the 0. 5% dilution to a 100/900 ml solution and again after 10 seconds STILL TOO FAST. Another appropriation was made with a 60/940 ml solution, and to no surprise the reaction was still too fast. While running out of options we finally decided to try one last solution of a 20/980 ml solution and found that after 10 seconds the iodine was finally purple.
We then kept timing with a 10 second interval, and at 20 seconds took another 25 ml sample and the starch was resolved and the iodine was then brown. While finding a way to slow down the reaction 10 seconds we found that a 20/980 or 1/50 enzyme to buffer it took 20 seconds for the amylase to break down the starch. Now with one more curiosity we tried a 10/490 solution and found that 10 seconds was purple, 20 seconds was purple, and that the starch was resolved at 30 seconds in brown iodine.
Conclusion: In this part of the experiment we learned that our hypothesis was correct and that the concentration was extremely important and needed to be changed drastically with dilutions to be able to see the effect in slow motion. PART II of enzyme vs starch experiment: After becoming quite good at being able to test enzyme to starch solutions we were to find out whether the pH of the buffer had an effect to the reaction time. Hypothesis: With learning that the amylase concentration is a big factor in the experiment we predict that the pH will have the same effect and that the lower the pH the faster the reaction time.
Procedure: With the same experiment set up and design we controlled the solution with what we left off and had a 10/990 enzyme to buffer solution, but changed the pH of the buffer. We then started out with a 4. 5 pH level and started mixing and timing. We timed in 5 second intervals and found that the starch lasted for 20 seconds. After learning that pH had a fast reaction time with an acidic pH level we decided to try a base pH level buffer of 8. 8. We then set up our products the same as the others with a test tube with 490 ml of buffer, then adding 10 ml of amylase solution, then finally adding 250 ml of starch.
We then started timing in 10 second interval. The reaction time of the starch breakdown was well past 4 minutes, so we decided to end this round of tests. With one more pH level to test, our hypothesis looked correct. With a 7. 4 pH level we used 20 second intervals with the exact same solution and found that it took starch a total of 4 minutes to totally break down. Conclusion: In conclusion to part II we discovered that our hypothesis was correct and that the more acidic the pH the faster amylase is able to break down starch.
Part III of Amylase vs Starch experiment: With the new understanding of amylase, starch, and pH level reactions the last variable we wanted to test was the effect temperature had on the reaction time. Hypothesis: Our hypothesis was that the hotter the water the faster the reaction time of starch breakdown. Procedure: Starting with 990 ml of 7. 4 pH buffer, 10 ml of enzyme, and 250 ml of starch floating in a floating test rack in a water bath of 80 degree Celsius heater water we let the experiment elements heat up for two minutes before we started mixing and timing our solutions.
After letting the elements heat up we mixed our solution and started timing with 10 second intervals and found that once the starch was added to iodine the reaction was profusely purple. We timed until 4 minutes and discovered that the starch never broke down. Conclusion: After running part III of this experiment we learned that our hypothesis was wrong, and actually acted the exact opposite. Heat slows down the enzymes ability breakdown of starch immensely. We were unable to get the starch to break down with so little time. The cooler the environment the faster the amylase enzyme is able to break down starch.
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