Investigating the Effect of Temperature on the Permeability of the Cell Membrane of Beetroot

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Aim: In this investigation I will be measuring the effects of temperature on the membrane permeability of beetroot. I will be measuring the amount of anthocyanin that will diffuse out of the beetroot. The way in which I will measure the anthocyanin is to check the light absorbency of the solution using a colorimeter. The higher the reading on colorimeter the more anthocyanin present in the solution

To find out the permeability of the beetroot membrane I will firstly cut out cylinders of beetroot using a cork borer, I will slice them into a certain width and then place them into distilled water at different temperatures. Using a colorimeter I will measure the anthocyanin that will diffuse into the distilled water, the higher the reading of the colorimeter the more anthocyanin leaked out by the beetroot hence a higher the rate of diffusion. EquipmentReasons for use…

ColorimeterThe colorimeter will measure the amount of light absorbed by the pigment in beetroot. The higher concentration of anthocyanin equals a higher reading on the colorimeter. A colorimeter will give an accurate measurement of the light absorbed by the pigment. The precision of the colorimeter is to two decimal places. I must make sure the cuvette has no finger prints on the clear side as the prints may absorb light itself making my results inaccurate. Measuring cylinderThe measuring cylinder will be used to ensure accuracy, and increase precision in the volume of water that I will be using. It will be used to measure the amount of water that the beetroot will be placed into; it must be the same for all the tests as the volume of water will affect the concentration of the pigment. If the concentration is different I will not be able to accurately compare the results and draw a fair conclusion. When measuring the volume of water it will be measured from where the meniscus sits, the meniscus must sit on the amount of water that I will use; this will in turn ensure accuracy, the precision of the measuring cylinder is to 1 d.p. The measuring cylinder will be in cm³ increasing accuracy. Cork borerA cork borer will be used to cut the beetroot into cylinders. A cork borer has a fixed circumference and will cut all the beetroot to the equal circumference which means the test will be fairer and the results will be more accurate. The cork borer is sharp, and so I will have to be careful when using this. RulerA ruler will be used to measure the length and surface area of the beetroot. This will ensure that all the pieces are of the same length so the test is fairer and the results in turn are more accurate. If the lengths are not equal the surface areas will be different and as surface area directly affects the rate of diffusion my results will be unfair so I will have to measure the beetroot carefully. The precision of the ruler is to 1 d.p for each mm. ScalpelThis will be used to cut the beetroot as it has a fine sharp edge. The beetroot will need to be cut at a 90º angle, increasing precision of the end results, as the surface areas will be equal due to it. This means that the beetroot slices will have the same surface area; this will ensure precision in results and provide a fair test as the exposed membrane will be equal to each other. I will have to be careful when using the scalpel as it is sharp, and so I will have to keep it away from my fingers. Distilled waterThe distilled water will be used for many things during my experiment. It will be used to clean all apparatus before it is used and it will also be used to rinse the pigment found on the beetroot, this ensures precision as pigment found on the surface area is not meant to be measured, we only want to measure the pigment that diffuses OUT of the membrane. It will ensure the experiment is not influenced in any way that it is not meant to be. Boiling tubeThe boiling tube will be used to hold the water that pieces of beetroot will be placed into. It also allows the contents of the...
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