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AN INVESTIGATION INTO HOW TEMPERATURE AFFECTS THE PERMEABILITY MEMBRANE OF A BEETROOT. TASK IN BRIEF For this experiment, I am investigating the effect of temperature on the permeability of a beetroot membrane. First thing I did was I measured out 5 100cm� of distilled water, and placed them into 5 different temperatures. Using the cork borer, I cut out one cylinder for each temperature, and then trimmed to a length of 2.5cm. After, I put the trimmed beetroot into the 5 different temperatures and left them for 25minutes. After 25miutes, I decanted the liquid containing the leaked beetroot pigment at each temperature into a cuvette, and then placed it into a calorimeter which has a blue filter. Then I measured the percentage light transmission for each temperature. And lastly I collected results for others in class to use it for comparison. PREDICTION I believe that more betalain pigment will be released from the beetroot as the temperature increases. High temperatures may distort the active site of the carrier affecting the shape of the fluid mosaic model membrane. The increase of kinetic energy will speed up the diffusion rate of the red pigment to a point. Then the structural damage of the membrane and the denatured proteins will increase the amount of red pigment escaping out of the cells. TABLE OF RESULTS Table to show the percentage light transmitted through a beetroot pigment (betalain) at different temperatures in an experiment to investigate the effect of temperature on the permeability of a beetroot membrane. Transmission of light through test cuvette (%) Temperatures (�C) 1 2 3 4 5 6 7 8 9 10 11 Mean Averages Standard Deviation 5 5.0 10.0 16.0 10.0 6.0 8.0 5.0 5.0 10.0 9.0 18.0 9.3 4.4 18 9.0 9.0 5.0 8.0 15.0 6.0 10.0 12.0 9.0 8.0 9.0 9.1 2.7 35 8.0 7.0 5.0 7.0 4.0 6.0 5.0 9.0 3.0 5.0 9.0 6.2 2.0 54 8.0 7.0 4.0 6.0 4.0 4.0 4.0 6.0 4.0 4.0 7.0 5.2 1.4 67 7.0 5.0 4.0 6.0 4.0 3.0 4.0 5.0 4.0 4.0 6.0 4.7 1.2 * These are all the group results. ...read more.


Cholesterol role is different compared to protein and phospholipid, its role is to give the membrane support and strength. Cholesterol determines how fluid the membrane is. It helps to control the fluidity; stopping it from becoming too fluid or too rigid, preventing the membrane from bursting. Cholesterol structure is very similar to a phospholipid; it too has a hydrophilic head and hydrophobic tale, which allows it to fit neatly in the phospholipids. Glycolipids and glycoproteins role is to help stabilise the membrane, with their carbohydrate chains that extend out into the water surface forming hydrogen bonds with the water molecules. Lastly, the lower the temperature the more light is transmitted because less concentrated betalain pigment is produced due to the membrane been not very permeable. And for the higher temperature, the less light is transmitted because more concentrated betalain pigment is produced due to the membrane been more permeable. Since the lipid bi layer gives the membranes its fluid characteristics. And at low temperatures, the bi layer is in a gel state and tightly packed. But at high temperatures the bi layer "melts' and the interior becomes fluid allowing the lipid molecules to move around, rotate and exchange places. This also allows movement of other components of the membrane. And this fluidity in the membrane has caused a great leakage of the betalain pigment in the beetroot's membrane. EVALUATION The procedure is suitable because I obtained the result I expected i.e. as temperature increases, the membrane becomes more permeable. The equipment used are mostly accurate (e.g. the water baths), because it allowed us to carry out the experiment in an expected way. The prediction does however matches with the results derived from the experiment, which concludes that high temperatures does makes the membrane more permeable due to the membrane becoming more fluid. The two anomalous results for 5�C is 16% and 18% light transmission. ...read more.


2. Some part of the cell membrane were damaged during cutting, resulting in some betalain pigment been leaked. And some f us will have more damaged or leaked betalain pigments than others which shows to be an error. Blot the beetroot out before inserting it into the distilled waters. This will remove any betalain pigment already leaked. If all leakage is wiped clean, then more precise results will be obtained because there isn't any betalain pigment in the water before the real damage occurs to the membrane. Numbers is used to rank the error in accordance to how each limitation will have the most or the least impact on the experiments. 1 for most and 7 for least. Overall, the evidence is quite reliable in showing that higher temperature does have an effect on the permeability of a beetroot's membrane. The main source of error is using a wide range of temperatures. The temperatures used for this experiment are too widely spread i.e. from 5�C to 18�C to 35�C etc. if a closer range of temperatures is used, then the result would have been more reliable than it is. Another main source of error is not blotting out the beetroot to remove leaked betalain pigments before putting it in distilled water. This is because the membrane is already damaged, and blotting it out removes all leaked pigment, this means more precise results will be obtained. An error with the least impact is the straightness of the beetroot because we are not measuring how straight the beetroot is, but how easily permeable the membrane of the beetroot is. Straightness does not have much of an impact on the permeability of a beetroot's membrane. If all improvements is taken into use when doing this experiment again, then the result obtained will be far accurate than the one I have now. Finally, the beetroot gives a good representation of the theories behind the plasma membrane and how it behaves but it does not give a good representation of the whole eukaryotic group because their behaviour may differ to others. ?? ?? ?? ?? - 1 - ...read more.

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3 star(s)

*** This report unfortunately lacked a discussion of variables or a written method for the experiment. There was class data analysis and detailed discussion of the results in the conclusion. The evaluation looked at some of the sources of error and proposed some procedural changes to improve the reliability of the results.
Research and rationale
There was a good deal of thorough background detail that could have been used to help plan the investigation but this was unfortunately all found in the conclusion to the experiment.
A testable hypothesis was formulated and stated concisely. This could have been improved by making the prediction quantitative. There was no planning included in this report and no written method. The key variables need to be described,the apparatus listed and justified and a full method included. No risk assessment was included.
A reasonable range of temperatures were investigated but no replicates were carried out. Class data was recorded and analyzed in a suitably headed table. Standard deviation was used to analyze the data further. There was a fairly low degree of precision but the results seem to follow an expected pattern.
Analyzing and Evaluating
The trends and patterns in the data were recognized and related to fairly sound biological knowledge. The graph was not included. The limitations of the results were commented on. To improve . The candidate is aware that the results may not be entirely reliable but has not proposed any great changes to the method to ensure the results are more valid. There was a sensible proposal to extend the work by using a smaller interval between temperatures.
The layout of the report does not conform to that expected for a scientific paper in that there is no written method and the discussion of background theory comes at the end of the report. No references were used to inform the planning of the report. Spelling, punctuation and grammar were of a reasonable standard with appropriate technical terms used throughout.

Marked by teacher Stevie Fleming 01/01/1970

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