Internal Assessment on Enzyme Concentration Essay

Maria Nica Biology 10. 10. 2012 Internal assessment on enzyme concentration Enzymes are proteins that act as catalysts and they are the most important type of protein. My aim in this experiment was to investigate the effect of enzyme concentration on the rate of an enzyme (protease) – catalyzed reaction , catalysts speed up chemical reactions .

My hypothesis is that the rate as reaction will increase as the concentration of protease in the solution increases so it will take less time for the reaction to take place . This is because the rate of an enzyme-catalysed reaction depends on the concentrations of enzyme and substrates ; as the concentration of either is increased the rate of reaction increases. The following tables show the data collected by group 10 during the experiment . Table 1 shows the time taken for every reaction to become clear . in group 10 ) Reaction | Time taken | Conversion in seconds | C| 2min 00s| 120| D| 2min 27s| 147| E| 2min 12s| 132| F| 2min 43s| 163| G| 2min 36s| 876| As you can see we don’t the the reactions A and B because their reaction didn’t take place .

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The time taken to become clear was more than 10 minutes , and as was written in the instructions we had to omit those reactions . Table 2 shows the average time taken from all the 14 groups for each reaction to become clear. To calculate the averages I added all the times in seconds taken for each group per reaction and divided at 5 ( number of reactions ) . Reaction | Time in seconds | C| 92. 31| D| 95. 39|

E| 169. 87| F| 130. 53| G| 340. 62| Rate=1time taken by the reaction to take place I will calculate as an example the rate for the first catalyzed reaction , which is reaction C . Rate for reaction C=192. 31s=0. 0108. Table 3 shows the rate of reaction calculated for every trial . Trial | Rate of reaction | C| 0. 108| D| 0. 0105| E| 0. 0059| F| 0. 0077| G| 0. 0029| As we can conclude from the table above , the rate of reaction overall decreases as the amount of the enzyme protease decreases in the reaction , except of the reaction F in where is a small increase in the rate of reaction .

This graph will show the variation within the rate of reaction : After I presented you all the observations from the data collected from the 14 groups , I will present you the observations collected from our group during the experiment . As I said above 2 of the reactions didn’t take place and this are the observations made on them. Test Tube A – The content of tube A was almost clear , only with tome milk particles floating into the solution . When we shook the tube the precipitation goes to the buttom and the temperature was constant at 36 degrees .

Test Tube B – The content of tube B was cloudy and some parts of the milk particles were on the bottom. In comparison with tube A when tube B is shocked the precipitation doesn’t sink to the bottom and the temperature was different as well , at only 35 degrees . Test Tube C – When test tube 1 is poured in tube C , the mix becomes very cloudy and the precipitations are allover the solution . It takes 2min and 62 sec for the precipitation to go down , to the bottom. Test Tube D – When test tube 2 is poured in tube D the mix goes also very cloudy ut the precipitation tends to go up . Most of the particles tend to stay up and it takes 2 min and 27 sec for the precipitate to sink to the bottom . Test Tube E – When test tube 3 is poured into test tube C the particles slowly sink to the bottom , the duration being 2 min and 43 sec . Test Tube F – When test tube 4 is poured into tube F the precipitation first is very cloudy but it sinks quite quickly , in comparison with the other tubes . The time taken for the precipitation to sink to the bottom is 2min and 43 sec .

Test Tube G – When test tube 5 is poured into tube G the mix is very cloudy and it takes a relly long time for it to sink until the bottom , 7min and 36 sec . Another experiment was made in a pre-IB class because it was an uncertainty in ours . Because the powder milk wasn’t mixed properly with the milk solution it was claimed that the data collected in the first experience was not reliable . They did the same experiment but the only difference was that the powder milk solution was boiled at 80 degrees .

Table 4 shows the new data from the pre-IB class . Reaction| Trial 1 | Trial 2 | Trial 3 | Trial 4 | Average | 1-C| 214| No reaction| 42| 120| 125. 33| 2-D| 171| 139| 92| 180| 145. 50| 3-E| 263| 162| 120| 252| 199. 25| 4-F| 325| 240| 180| 359| 276. 00| 5-G| 504| 360| 421| 720| 501. 25| I will calculate again the rate of reaction for this experiment using the same formula and I will show the results in table 5 . Trial| Rate of reaction| 1-C| 0. 0798| 2-D| 0. 00687| 3-E| 0. 00502| 4-F| 0. 00362| 5-G| 0. 00200| As we can see from the data obtained , there is only a continuously decrease in the rate of reaction , not as in our experiment where there was also an increase for test tube F . This is the graph that shows the decrease in the rate of reaction :


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