Investigating the Rate of Respiration in Yeast: Triple/double science Biology coursework for GCSE - page 5
Keywords: Investigating the Rate of Respiration in Yeast: Triple/double science Biology coursework for GCSE, anerobic respiration, A, Higher Level
By Glamurus on 02/11/2006 17:54:57
Level: GCSE Key Stage 4 (Years 10-11)
Page Number: 5 of 6 pages: 1 2 3 4 5 6
a higher concentration of water in the yeast cells than the experiment apparatus. This happens in my experiment at 8% and 10% glucose concentrations. The second part of my prediction was wrong.
Evaluation
My data is fairly reliable because both repeats give the same pattern of results. My results were also precise because I was measuring to 0.1cm³. It was hard to get extremely accurate results because of yeast being a living thing and that this experiment includes other variables that are difficult to control such as the age of the yeast, biological differences between individual yeast cells that will always exist in living things and temperature control. This makes this particular investigation harder to regulate than a similar one based on chemical reaction, a reaction between hydrochloric acid and magnesium ribbon for example.
Ways that I could improve my investigation or verify its results better are by extending the range of the dilution of glucose solution. I could have also tried 12%, 14% and 16%, for example. Another thing I could have done is carried out more repeats.
As already described, I had an anomalous result at 2% glucose concentration that I have omitted from the average result at that concentration. There are many things that could have caused this to happen. The delivery tube that carries the gas produced by the yeast cells to the burette could have been much further up the burette than in the other repeats. The temperature of the water in the experiment could have been much warmer than in all the other repeats. Both of these are human errors to do with the set up of the equipment.
I think that my results are good enough to give a reliable conclusion because the data is accurate (apart from one anomalous result) and the repeat results are close together, the method was a fair test, the results follow scientific theory and if another person tried the same experiment they would arrive at roughly the same conclusion.
I could extend my investigation by finding out how the age of yeast affects the rate of respiration. For example, I could test the yeast at 5 minutes after being made up, 10 minutes after, 1 hour after, 5 hours after, 24 hours after and so on.
I could improve this experiment by using a thermostatically controlled water bath and an accurate
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