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While molecules in diffusion move down a concentration gradient, molecules during osmosis both move down a concentration gradient as well as across it. Both diffusion, and osmosis are types of passive transport, which do not require help. When the concentration of the environment outside of the cell is lower than the inside of the cell, this is called a hypotonic solution. In hypotonic solutions, when water moves into the cell they burst, which is known as lists. A hypersonic solution is when the concentration of outside the cell is higher than the inside of the cell.
In hypersonic solutions, water moves out of the cell, making the cell lose water and shrink; this is called creation. An isotonic solution is when the concentration of dissolved molecules is the same both inside and outside of the cell. Thus there is no net movement. The purpose of this experiment is to investigate whether osmosis occurs across the membrane of potato cells. Hypothesis The potato that will be more hypersonic to the sucrose solution will gain weight, whereas the potato when hypotonic to the solution will lose weight. When the potato is most isotonic the similarity of the potato will be 0. . Materials 1 potato 7 250-ml Beakers Sucrose Solutions: 0. 1 (M) Razor Blade Denizen Water (0 molar) Balance that weighs to the nearest 0. 01 Cork Borer Paper Towels Calculator Metric Ruler Methods To perform this experiment seven 250-ml beakers were obtained, rinsed thoroughly and dried with a paper towel. Next a small amount of tape was applied on the beakers and labeled accordingly to the sucrose solution molarities. Each beaker received 100-ml of the various solutions. However one beaker received 100 ml of Denizen water with a molarities of 0. . Afterwards a cork borer was pushed through the potato and was twisted back and forth. Once the borer was filled it was removed from the potato. Pushing the potato cylinder out of the borer, this this step was repeated six more times in order to get seven undamaged potato cylinders. Using a sharp razor blade, the potato cylinders were both cut to a uniform length of about CM, and were removed of their potato skins. The potato pieces were also cut in half to give the cells a greater reface area in which it was easier to absorb the solution.
After the cylinders were weighed on a balance and the data was recorded in Table 4 Using the razor blade each potato was cut lengthwise into two long halves. Then the potato pieces were transferred to the water beaker and the time they were submerged was recorded. This step was repeated for all potato cylinders in which the pieces were placed in solutions O. 1 to 0. 6 M. The potatoes were incubated for ninety minutes. At the end of the incubation period the time was recorded. Then the potato piece was removed form the first sample.
Next potato pieces were weighed the and the final weight was recorded in Table 4. This procedure was repeated until all samples had been weighed and recorded in the chronological order they were initially placed in the test solution. Afterwards the table was completed by recording the weight change and percentage change. In order to calculate the final percentage change of weight the formula that would be needed is (weight change)/(initial change) X 100. The data received at the end was not normal; therefore each potato cylinder was weighed again, and recorded on two different scales.