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Establish the cytoplasm concentration of carrot cells.

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Introduction

Biology Carrot Experiment Aim: To establish the cytoplasm concentration of carrot cells. Method * Use a pipette to measure the different volumes of sucrose and distilled water into six test tubes (use different pipettes for water and sucrose solutions to avoid contamination). In the following ratios in order to get the correct concentrations correct. Sucrose Concn Volume of sucrose cm3 Volume of water cm3 0 0 20 0.2 4 16 0.4 8 12 0.6 12 8 0.8 16 4 1 20 0 * Use a scalpel to cut 18 even-sized pieces of carrot approximately 10x5x5 millimetres in size. * Weigh three pieces of carrot then place them into one of the test tubes containing the sucrose solution and cover with Clingfilm. ...read more.

Middle

During this period the carrot cell cytoplasm has a lower water potential than the surrounding solution; subsequently water particles diffused through the partially permeable membrane of the carrot cells along the diffusion gradient in to the cells resulting in a mass increase. At the point (0, 0.38) the carrot maintained a constant mass as the water potential of the two solutions were the same and therefore isotonic. There is equal movement of water particles between the two cells so we say there is no 'net movement' of water. Therefore the concentration of the carrot cell cytoplasm must therefore be 0.38M. After this point the carrot cells lost water to the surrounding sucrose; this is shown by their loss of mass. ...read more.

Conclusion

I could improve my method by cutting my carrot into more uniform sizes (possibly by using a cutting template specialised device)as they varied slightly in shape which would have meant a reduced surface area for some pieces of carrot; thus less cells are exposed to the solution so there is likely to be less water movement. I could repeat the experiment to get more reliable results; as well as test a smaller range of results surrounding the 0.3-0.5M range to get a more accurate idea of the carrot cytoplasm concentration (for example 0.30, 0.35 etc.). I could also leave the carrot/sucrose solution for longer and cut the pieces thinner to allow all the cells in the carrot sample to lose or gain the water. This will give us a better idea of the actual concentration of the carrot cytoplasm concentration. ...read more.

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