Yeast Respiration Experiment

Yeast Respiration Experiment

Temperature (°C)

[IMAGE]Number of Bubbles

10

0

20

14

30

17

40

17

50

19

60

24

70

35

80

48

Data Analysis and Conclusion

The data shows a clear rise in yeast respiration as the temperature is

raised. Although an optimum temperature is not evident, it can be seen

that temperatures exceeding 60°C speed up the reaction. This shows the

general rule that reactions become faster when the temperature is

increased. Unfortunately this data does not seem to show an optimum

temperature for the enzymes in the yeast to function properly, which

would be expected normally.

There are several weaknesses that would have definitely decreased the

accuracy of the experiment by a noticeable amount.

Firstly, the temperature of the yeast itself probably would not have

been equal to the temperature stated on the thermometer. The

thermometer was in the beaker of water, adjacent to the flask, but the

amount of time given for the yeast to equalize temperature to the

water temperature may have been too short. A thermometer actually

going through the cork into the flask through its cork would have

provided much more accurate temperature readings, and therefore a more

accurate experiment.

Secondly, the expansion of the air in the flash due to its heating up

was not taken into account. As the temperature increased, the

expansion would have been constant, but when the actual CO2 from the

yeast was produced, we were unable to determine what was actually

coming from the yeast. If there was a predetermined amount of air in

the flask and tube, and its expansion was taken into account, this

would have helped make the experiment more accurate.

Thirdly, no control was used in the experiment to make reference to. A

flask filled with water (to the same volume as the yeast) would have

provided sufficient control on the experiment.