Macromolecules and Digestion Practical Investigation

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Individual and Collaborative Skills

Collaborative Skills

Throughout this practical investigation, many collaborative skills were used. During the investigation, communication skills were required when starting and stopping the timer in order to obtain reliable results. Collaborative skills were also required to determine at what point the timer should be stopped, based on the colour of the solution.

Individual Skills

Several individual skills were required throughout this investigation. When preparing each trial, measuring skills including using a dropper and calibrated pipette were required in order to measure the correct amount of each solution and obtain reliable results. Other individual skills including using a thermometer to measure the temperature of the solution in the test tubes and the temperature of the water in the water bath were also required during this investigation.

Data Presentation

Figure 2.1- Time Taken for Reaction to Take Place, Shown Via Colour Change

Time (seconds)

Temperature

Trial 1

Trial 2

Trial 3

Trial 4

Average

19°C

121

113

116

96

112

38°C

37

38

39

40

39

57°C

185

197

210

192

196

74°C

300

300

300

300

300

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[pic 3]

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[pic 4]

Pattern and Trend

The trend in the graph in figure 2.2 above demonstrates that both high and low temperatures impact the speed at which the lipase breaks down the fat in the milk to fatty acids will also increase. This is evident due to the convex parabolic line, demonstrated through the increase in time taken for a reaction to take place in temperatures above and below approximately 38°C, where a 19°C solution took an average of 112 seconds for a reaction to take place, while solutions heated to 58°C took an average of 196 seconds for a reaction to take place. Test 4, with a water bath of 73°C was the most precise due to the fact that the points are extremely close, while Tests 1 & 3, with water baths of 19°C and 57°C were the least precise as the points are further apart.

In this practical investigation, it is shown in figure 2.2 that the 4th trial in the first test is an outlier, as a reaction took 96 seconds to take place while the average for this test is 112 seconds.

Due to the fact that the optimum temperature for enzyme activity is approximately 38°C, the rate at which the lipase breaks down the fat to fatty acids is significantly lower than other temperatures. This supports the hypothesis, which states that as the temperature increases, the speed at which the lipase solution breaks down the fat in the milk to fatty acids will also increase.

Conclusion

This practical investigation showed results that supported the hypothesis, which stated that as the temperature increases, the speed at which the lipase solution breaks down the fat in the milk to fatty acids would also increase. This was seen as the average time taken for the lipase to break down the fat in the milk to fatty acids was 112 seconds when the solution was heated to 38°C, while the time taken for a reaction to take place in a solution heated to 74°C was not able to be determined due to time restrictions and the denaturing of the enzyme. These results occurred due to the fact that the optimum temperature for enzyme activity is approximately 38°C, thus a reaction took place in a very short amount of time.

Discussion

Analysis of Errors

Throughout this investigation random and systematic errors may have occurred. A random error is one that occurs due to human error and can be detected by outliers. One random error that may have occurred throughout the duration of this practical investigation was not creating each solution in exactly the same way. When first completing the investigation, the method previously created was incorrect, thus different volumes of each solution had to be used. This may have caused a random error, and created unreliable results. Another random error that could have occurred during this practical investigation could have been not heating each solution to the exact temperature. This creates unreliable, varied data, resulting in higher or lower reaction times.

A systematic error is caused by the equipment that is involved in the investigation. In order to avoid systematic errors, the investigation should be repeated with new equipment. However, this was unable to be completed due to the short time frame and urgency of the completion of this practical. A possible systematic error that could have occurred during this investigation was the incorrect heating of the water bath. As it is very difficult and time consuming to heat the water baths to equal temperatures and keep it at that specific temperature, the data becomes unreliable and imprecise.