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osmosis in potato cell

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OSMOSIS IN POTATO CELLS Osmosis is the diffusion of water molecule of water through a partially permeable cell membrane from a high concentration of water to a low concentration. It is a type of passive transportation as it does not require the expenditure of energy. This means that water will travel across a partially permeable membrane (ppm) from an area of high water concentration to an area of low concentration until the concentration in both areas is equal. Osmosis happens in plants and animals and its participation is essential in various biological processes which take place in our organism such as the absorption of water from fluids. In this experiment we deal with plant cells which are those found in potatoes. According to the theory which osmosis presents, of the concentration of water is greater on the inside of cells, water molecules will go across the partially permeable membrane. This will reduce the volume of cells because they contain less water and thus they will shrink. If, on the other hand, the concentration of water is greater on the outside of cells, they will go across the membrane and inside the cells. This change in volume contained in the cells will make them go turgid and it is only the cell wall which will prevent the potato cell from bursting. ...read more.


in all solution concentrations and a best fit line: The following graph shows all sucrose concentration data with the purpose of finding a best fit line according to its sucrose concentration and thus a clear relationship between the two variants presented: We can appreciate that, as the concentration of sucrose increases the percentage change in weight of the potato decreases from an increase of 9% in weight, in a distilled water or 0M sucrose concentration solution, to a decrease in weight of 20% in the beaker containing a solution of 0.9 M sucrose concentration. This is more clearly shown in the best fit line (in black) as opposed to the actual data line (in blue). This means that these two variables (the percentage change in weight and the solution concentration) are inversely proportional or share a negative correlation. Discussion Conclusions: As we can appreciate from out results, the amount of sucrose concentration in solution greatly affects the weight of the potato sample. As the amount of sucrose concentration increased, the weight of the potato decreased. This clearly proves how osmosis took place. In a 0M sucrose or distilled water solution, the concentration of water molecules was greater outside and cells will travel across the ppm of the potato cell to try to balance this difference in concentrations, increasing the amount of water inside the cells. ...read more.


Sucrose is, as it is known, a disaccharide consisting of a molecule of glucose and one of fructose. Its small structure makes it easier to dissolve in solution. On the other hand, starch is polysaccharide of a large structure. This means it is more difficult to dissolve it and when tried to do so in water there will we spaces between the polymer chains containing water molecules, unlike sucrose where all the spaces in the water solution will contain this disaccharides molecules. This means that the gradient or water concentration of starch remains unaffected and thus water molecules do not have the need to cross the ppm as the strength of water between starch molecules remains; in those gaps there is only pure water molecules (if distilled water is used).The properties of these two carbohydrates can be shown in several processes performed in organisms of both animals and plants. When plant cells store glucose, water which will assumedly have a lower concentration will travel across the gradient, entering the cells and limiting storage capacity. However, if they store starch, a gradient is not created so storage capacity is increased. This is also shown in the liver when our organisms store starch when storing carbohydrates. Since animal cells do not own a cell wall, they have the risk of bursting if they store much sucrose because water molecules would enter the cell to level the water concentrations and it volume would increase. Marielle Alvino ...read more.

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