By Thomas Pelikan
Biology 200A
Section 004
Kimberly Schmidt
October 2, 2012
Abstract:
In this experiment we were trying to determine the osmolarity of potato tubers by weighing them before and after incubating them in solutions of sucrose with varying molarities. To find the osmolarity we took a potato and used a cork borer to obtain seven samples of potato tubers. We then prepared seven beakers with concentrations of sucrose ranging from 0.0M to 0.6M. After weighing the potato tubers one by one we cut them in half and placed each halved tuber into each beaker. We incubated them for 1 hour, stirring every 10 minutes. After one hour we removed the pieces and weighed them and compared the initial and final weights to find the percent change in weight for each solution. The results showed that the 0.0M-0.3M solutions increased the weight of the potato tubers. The 0.4M solution of sucrose only increased the weight by 0.47%. The sucrose solutions of 0.5M and 0.6M increased the weight of the potato tubers. The sucrose solutions of 0.0M to 0.3M increased the weight of the potato tubers, supporting our hypothesis. The sucrose solution of 0.4M only slightly increased the weight of the potato tubers, supporting our hypothesis that the osmolarity of the potato tubers was 0.4M. The sucrose solutions of 0.5M and 0.6M increased the weight of the potato tubers, which did not support our prediction that the weight should decrease, but that was most likely due to errors in removing excess solution from the potato tubers after removing them from the solution.
Introduction: Determining osmolarity in plant cells is important to scientists when performing experiments. In order for normal physiological processes to occur in plant cells, the plant cell must be in an isotonic solution; it must have the same amount of osmotically active substance (OAS) inside the cell as well as outside the
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