I also worked out the rate of reaction; this was done by 1/time which in this circumstance was seconds. This shows how quickly it took for the casein and trypsin to actually react. The rate of reaction depended on two things which were: the regularity of the collisions between the particles and the energy through which the particles collide. This table shows the rates of reaction for the various temperatures.
BIOLOGY COURSEWORK PAVAN AULAK 11AV
Interpretation
Graph 1 shows how long it took for the milk solution to become colourless as the temperature of the casein and trypsin is increased. In general the graph shows that when the temperature increases the time taken for the solution to become transparent decreases but when the graph reaches 60°C the graph shows that the time for the milk to clear took much longer. The line of best fit is a curve as it was most appropriate; a straight line of best fit could not be drawn as the last piece of data did not fit with the others and from my background knowledge I know that it is roughly in the correct place. The graph starts of with a strong negative correlation but then suddenly drops. This graph is not directly proportional as there is no direct link through out the graph between the temperature and the time taken for the solution to become colourless. Another test for proportionality is to see whether a straight line goes through the co-ordinates (0.0), this clearly is not the case on my graph. I also tested to see whether the graph was inversely proportional; the simply way of doing this is to see if one variable gets bigger as the other gets the smaller. This clearly not the case on this graph as when the temperature reaches 60°C the time it takes to clear is also quite long. From 6°C to 50°C the time it takes to clear starts to decrease as the temperature increases this because the molecules begin to move faster. For any reaction to happen the molecules have to collide so at higher temperatures the molecules have more energy; with this energy they will collide more frequently causing the time it takes for the solution clear decrease. The temperatures when the solution became transparent were at 39°C and 49°C. The explanation why this happened is because enzymes work best at 37°C in the human body. This is called the optimum temperature. This is the correct temperature for molecules to have most energy and therefore collide more often causing the reaction to happen faster. The last phase which is very noticeable on my graph is that it curves extremely steeply from 50°C to 60°C; the time it takes for the solution to become colourless is much longer than the other temperatures. Above a certain temperature enzymes stop working and therefore the reaction stops this clearly not the case on my graph because the reaction does happen but takes a much longer time. At high temperatures the molecule will not fit in the enzyme so the reaction is unable to take place. The reason it does not fit is because the active site has been changed, the enzyme will have been denatured.
Graph 2 is rate of reaction graph to show quickly the casein and trypsin reacts together. Generally the graph shows that the temperature increases the rate of reaction also increases, but when the temperature reaches 60°C the rate of reaction decreases dramatically. The graph is not directly proportional but it is almost proportional because as the temperature increases by roughly 10°C the rate of reaction also increases by roughly 0.01sec. The graph is not linear as the line of best fit is curved and all the points do not follow the same line. This graph is also not inversely proportional because as one increase the other also increases but if it was inversely proportional one would have increased as the other decreased. The graph curves most steeply when the temperature changes from 50°C to 60°C. At the beginning of the graph the lie curves smoothly. At low temperatures the molecules have low energy and therefore do not collide very often this means that the rate of reaction is low. The graph shows that the rate of reaction is highest between 39°C and 49°C, this is because enzymes work best at this temperature; the molecules have more energy which in turn means that they move more quickly and colliding more often. The more collisions mean the more reactions which will mean that the reaction will happen much faster. From 50°C to 60°C the rates of reaction this is because past a certain temperatures the enzymes become denatured and the active site is changed so the molecules are unable to fit into the active site.
BIOLOGY COURSEWORK PAVAN AULAK 11AV
Evaluation
Altogether I collected 54 pieces of data; I believe these were enough results to draw a conclusion because they supported the scientific knowledge that I had researched. These are fairly accurate but there were some temperatures where the spread of data was wide spread so these temperatures should be re-done. On my graphs all my results fit the line of best as I excluded my outliers before plotting the graphs. I believe that the results for 60°C should be repeated as it has a wide spread even with the outliers excluded and it needs to be more accurate. For some temperatures the repeated measurements should be repeated because the differences are significant which can make the results slightly unreliable. I believe that my results have covered a big enough range to support a firm conclusion because my graphs show the highest and lowest parts. To get a accurate and firm conclusion I would have like to collect data at every 5°C intervals because on graphs there are ‘blind spots’ where I am unable to see where my graph should peak. This would have also allowed me to get a greater understanding of how temperature effects the time it takes for the solution to clear and the rate of reaction. This would have also allowed me to plot of my line of best fit more accurately.
There were a few problems with the scatter of data as it was so wide spread. There could be a number of reasons for this some of which are: that the window was open near the water baths and people but there solutions into the water baths at different times so if the wind from outside hit the water baths then the temperatures could have fluctuated slightly. Another reason why the data could have been wide spread is because the time taken for the ‘x’ to appear once the two solutions had been mixed would have depended of the users’ judgment. Another reason why is because we all had use the same beaker to do each temperature so some may have still been contaminated and not cleaned out properly, this would have then had an effect on the subsequent result. Other people’s temperatures may have also varied because the 10°C and 20°C was not in a water bath and therefore not thermostatically controlled. All my equipment was appropriate for the task, although it would have been better if we had more than one beaker so each temperature could have been done in a separate beaker as I believe that the previous temperature remained on the beaker which could have had an effect on the results. My results were accurate as I used a stopwatch instead of an ordinary clock. The divisions on the scale of equipment were adequate for the readings needed. From the equipment I used I expect the readings to be fairly accurate, although the water baths were quite big so I believe that there should have been more than one thermometer in one water bath as the temperature have been slightly different on one end to another. To make my results more accurate and reliable I would ensure that everyone did their experiment at exactly the same temperature and I would have left the solutions in the water bath a little longer so that temperature penetrated throughout the solution .
To make my conclusion more certain I would do the experiment again but with 5°C so I could get a better understanding of what is happening during these temperatures. To conclude I believe that the experiment was a success and that my results are precise enough to make a firm conclusion that as the temperature increases the rate of reaction increases and the time taken for the solution to clear decreases but once the temperature has gone past 50°C the enzymes start to become denatured and the rate of reaction decreases and the time taken for the solution to clear increases.
