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Investigating the effect of Temperature on the Cell Membrane of Beetroot Cells.

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Investigating the effect of Temperature on the Cell Membrane of Beetroot Cells Aim To investigate what effect temperature has on the integrity of the plasma cell surface membrane of beetroot cells. Background information Despite their many differences in appearance and function, all cells have a surrounding membrane (called the plasma membrane). The cell membrane of plant cells is an integral part of the cell as it controls the transport of substances needed by the cell such as water and molecules dissolved in the water (salts and glucose) both into and out of the cell. The actual membrane is a thin layer (8 to 10 manometers in width), which is partially permeable. It is composed largely of lipids and proteins. Most of the lipids on the cell membranes are triglycerides (they have one molecule of glycerol chemically linked to three molecules of fatty acids) and the skin of the membrane is made of phospholipids. These phospholipids are arranged into two layers of with the hydrophilic phosphate group on the outside, which 'protects' the hydrophobic fatty acid chains. The cells of a beetroot plant contain betalain pigments, which replace anthocyanins in plants within its plasma membrane. Betalain is found in the vacuole of beetroot cells and it gives the beetroot its characteristic dark purple colour. ...read more.


Five uniform cylinders were cut from the beetroot, trimmed to a uniform length and collected in a beaker of water. As the beetroot was cut, some of the outer cells membranes had been ruptured meaning that some of the betalain dye leaked out (as seen by the red dye on the white tile). This external dye had to be washed off in order to maintain the reliability of the results. This was done by leaving the beaker of beetroot cylinders in a running water bath over night. Diagram: After the preparation, the apparatus was set us as below. Main Experiment: A water bath was made using the beaker and water. This bath was heated to 85oC using the Bunsen burner. Once the water bath reached 85oC (measured using the thermometer) the Bunsen burner was turned off and the water bath allowed to cool. When the bath dropped to 80oC one piece of beetroot was placed directly into the hot water and left in for exactly 1 minute (timed by the stop-watch). When the minute was up, the beetroot cylinder was removed using the tongs and placed into one of the 5 test tubes along with some water to just cover the cylinder. ...read more.


There are several ways which this could have been achieved. Firstly, the results could have been made more reliable by repeating the experiment (triplicates), and also by taking more measurements (10 rather than 5). The results could also be made accurate in several ways. Firstly, the beetroot cylinders were not cut accurately, but only estimated. If the beetroot was cut more accurately, there would be a similar surface area on each cylinder and each cylinder would have the same potential to release betalain. Also, if the same volume of water was used to bathe the cylinders on each occasion (about 10ml), the amount of betalain released by each cylinder would be diluted equally and thus producing fair readings on the colourimeter. Also, the cylinders were left to stand for different amounts of time. For example, as the 80oC cylinder was done first, it was left to stand for the longest period of time, however the 40oC was left to stand for a very short period of time. In the future, the amount of time the cylinders are left to stand for should be measured (30 minutes seems like a good amount of time). If the colourimeter used was digital (not analogue), the reading of the % transmission could have been measured more accurately. Devesh Parekh ...read more.

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