LAB+TWO+Enzyme+Catalysis

Lab Report File ->


 * Enzyme Catalysis **

**Exercise 2B: The Base Line Assay** Base Line Calculation:

Final reading of burette = **37.1 mL** Initial reading of burette = **28.1 mL** Base line (Final - Initial) = **9 mL KMnO4**

**Exercise 2C: The Uncatalyzed Rate of H2O2 Decomposition**

Uncatalysed H2O2 decomposition

Final reading of burette = **32 mL** Initial reading of burette= **22.9 mL** Amount of KMnO4 titrant= **9.1 mL** Amount of H2O2 spontaneously decomposed (mL base line - mL KMnO4) = **-.1** What percent of the H2O2 spontaneously decomposes in 24 hours? [(mL baseline-mL 24 hours)/ mL baseline] x 100 = **-1.11**

**Exercise 2D: An Enzyme-Catalyzed Rate of H2O2 Decomposition** DATA OF THE BASELINE CALCULATION IS IDENTICAL TO THAT OF EXERCISE 2B

Table 2.1 Class Data:
 * KMnO4 (mL) || 10seconds || 30seconds || 60seconds || 90seconds || 120seconds || 180seconds || 360seconds ||
 * Base Line || 9 || 9 || 9 || 9 || 9 || 9 || 9 ||
 * Final Reading || 32.8 || 33 || 33.4 || 33.5 || 33.8 || 44.8 || 45.2 ||
 * Initial Reading || 32 || 32.8 || 33 || 33.4 || 33.5 || 44.2 || 44.8 ||
 * Amount of KMnO4 Consumed || 0.8 || 0.2 || 0.4 || 0.1 || 0.3 || 0.6 || 0.4 ||
 * Amount of H2O2 Used || 8.2 || 8.8 || 8.6 || 8.9 || 8.7 || 8.4 || 8.6 ||
 * Justin, Rachel, Vinny, Nick, Monica and Destini's group**
 * Time || 10 || 30 || 60 || 90 || 120 || 180 || 360 ||
 * H2O2 Used || 7.5 || 9.75 || 9.15 || 10.1 || 9.8 || 10.05 || 10.15 ||
 * Michelle, Vicki, Eric, Amal**
 * Time || 10 || 30 || 60 || 90 || 120 || 180 || 360 ||
 * H2O 2Used || 7.25 || 9.55 || 10.15 || 10.15 || 9.75 || 9.85 || 10.05 ||

Discussion: The purpose of Exercise 2A was to test catalase activity and the factors that affect it. It was observed that when H2O2 was presented with a catlase it formed water and oxygen. H2O2 was the substrate and it was broken down into new materials by the catalase. Another observation that was made was the fact that if catalase is boiled it will not react with a substrate. When a __catalyst__ **(enzyme)** gets too hot it denatures and can’t react with its correct substrate. __A final observation that was made was the presence of a catalase in living tissue__. **(Finally, it was observed that catalase is present in living tissue)** If a liver (living tissue) was was added to a solution of 1.5% H2O2 it would bubble and fiz. __The liver acts as a catalase to the__ **( the catalase in the liver acts as a catalyst, reacting with the)** peroxide and therefore water and oxygen are produced. This part of the lab was not actually conducted, but it was __hypothesized__ **(discussed)** by using common sense and former knowledge of the subject. This activity provides a jumping board for such questions like __if__ **(do)** all catalases in living tissue behave the way the liver does. Exercise 2B served the purpose of obtaining a base line for the rest of the lab. It was necessary to determine the amount of peroxide present in the solution initially so there was a way to determine the results for the rest of the lab. Titration was used to test the level of peroxide in the solution. By finding the difference between the initial and final level of the KMnO4 the baseline was calculated. It is very important to have a base line so it is possible to calculate the amount of H2O2 used. It is possible that too much KMnO4 was used during the titration of the actual baseline and that may have skewed the results. A question that may arise is if there is a more precise way to determine the base line other than titration. The purpose of Exercise 2C was to determine the rate at which the H2O2 solution decomposed. A small beaker of the H2O2 solution was left to sit for 24 hours. After the 24 hours, titration was used to determine the __change and percent change**(**__ **percent of decomposition)** in the H2O2 solution. The amount of KMnO4 was compared to the baseline to see a change in the amount of KmnO4 that was used. __It was very important to see how the solution decomposed because if that solution was used during the actual experiment the relationship between that solution and the baseline would have been off__. **( This sentence just confuses me. We did is part to determine the rate of spontaneous decomposition of H2O2. We never used the H2O2 that stood for 24hrs in the "actual experiment" because i that one we were determining the rate of catalyzed decomposition.)** This poses the question of how long it actually takes for the solution to decompose even the slightest amount. The results of Exercise 2D did not support the hypothesis. __The data that was presents in the results didn’t match the results that occurred were sporadic and didn’t match up with the hypothesis.__**(this is a run on sentence. and they weren't sporadic, they were very weakly linear)** __The purpose of Exercise 2D was to find how much substrate disappeared over time. The first part of the exercise was to establish a baseline. This was already done in section 2B because it was done in the same day as 2D. This was done by setting up seven beakers with the same solution and adding liver and sulfuric acid__.**( all this is just repeating the purpose and procedure and doesn't belong in the conclusion.)** As the time intervals at which the catalase was introduced to the substrate before adding sulfuric acid increased it was found that about the same amount of H2O2 was used up. Unfortunately these were not the results the hypothesis projected. The amount of H2O2 used up should have increased as the time intervals increased. This data may have been adulterated by leaving each beaker sit with the catalase for too long**,** or perhaps not long enough. __At this point in time an inhibitor may have been not having( **awkward wording)**__ two extra members of the lab group who could have helped interpret data more carefully.

(**overall you should draw some kind of general conclusion using the evidence. i also think you should go into more detail about why the results didn't corrolate and you should offer an alternative hypothesis. these are all on the check list)** Conclusion:
 * (our Hypothesis,)** If the enzymes react with the substrate for a longer time, then more substrate will be used up because the substrates will be in contact with the enzymes longer thus creating more products__. The hypothesis__ (**combine into one sentence)** was proven incorrect by the results of this lab.

Abstract:
 * ( clearly state that this is the hypothesis)** If the enzymes react with the substrate for a longer time, then more substrate will be used up because the substrates will be in contact with the enzymes longer thus creating more products. During the lab the nature of how catalysts and enzymes were explored including uncatalyzed rates of decomposition and enzyme-catalyzed rates of decomposition. This was explored by titration a H2O2 solution. **(include the results and conclusion)**


 * ps: don't hate me...**

Discussion: The purpose of Exercise 2A was to test catalase activity and the factors that affect it. It was observed that when H2O2 was presented with a catlase it formed water and oxygen. H2O2 was the substrate and it was broken down into new materials by the catalase. Another observation that was made was the fact that if catalase is boiled it will not react with a substrate. When a enzyme gets too hot it denatures and can’t react with its correct substrate. Finally, it was observed that catalase is present in living tissue. If a living tissue was added to a solution of 1.5% H2O2 it would bubble and fizz. The catalase in the liver acts as a catalyst, reacting with the peroxide and therefore water and oxygen are produced. This part of the lab was not actually conducted, but it was discussed by using common sense and former knowledge of the subject. This activity provides a jumping board for such questions like do all catalases in living tissue behave the way the liver does. Exercise 2B served the purpose of obtaining a base line for the rest of the lab. It was necessary to determine the amount of peroxide present in the solution initially so there was a way to determine the results for the rest of the lab. Titration was used to test the level of peroxide in the solution. By finding the difference between the initial and final level of the KMnO4 the baseline was calculated. It is very important to have a base line so it is possible to calculate the amount of H2O2 used. It is possible that too much KMnO4 was used during the titration of the actual baseline and that may have skewed the results. A question that may arise is if there is a more precise way to determine the base line other than titration. The purpose of Exercise 2C was to determine the rate at which the H2O2 solution decomposed. A small beaker of the H2O2 solution was left to sit for 24 hours. After the 24 hours, titration was used to determine the change and percent of decomposition in the H2O2 solution. The amount of KMnO4 was compared to the baseline to see a change in the amount of KmnO4 that was used. It was very important to see how the solution decomposed. Since the solution was decomposed it would have been unwise to use it because the relationship between that solution and the baseline would have been off. This poses the question of how long it actually takes for the solution to decompose even the slightest amount. The results of Exercise 2D did not support the hypothesis. The data that was present in the results didn’t match the results. They were very weakly linear and didn’t match up with the hypothesis. The purpose of Exercise 2D was to find how much substrate disappeared over time. The first part of the exercise was to establish a baseline. This was already done in section 2B because it was done in the same day as 2D. As the time intervals at which the catalase was introduced to the substrate before adding sulfuric acid increased it was found that about the same amount of H2O2 was used up. Unfortunately these were not the results the hypothesis projected. The amount of H2O2 used up should have increased as the time intervals increased. These did not correlate because something may have went wrong during the lab. Perhaps the data may have been adulterated by leaving each beaker sit with the catalase for too long, or not long enough. An inhibitor in this Exercise was not having two extra members of the lab group who could have helped interpret data more carefully. An alternative hypothesis may be that if we test catalyzed vs. uncatalyzed decomposition rates then we will be able to understand more about enzyme activity because we can determine what an enzyme does to a substance in terms of increasing reaction rates.
 * Fixed..............................**

Conclusion: If the enzymes react with the substrate for a longer time, then more substrate will be used up because the substrates will be in contact with the enzymes longer thus creating more products, the hypothesis was proven incorrect by the results of this lab.

Abstract: If the enzymes react with the substrate for a longer time, then more substrate will be used up because the substrates will be in contact with the enzymes longer thus creating more products. During the lab the nature of how catalysts and enzymes were explored including uncatalyzed rates of decomposition and enzyme-catalyzed rates of decomposition. This was explored by titration a H2O2 solution. The hypothesis was not supported by the results of this lab.