Osmosis Lab Report PDF

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Lab report I completed for the Osmosis lab we did....

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1

Testing Potato Core Samples in Sucrose Solutions to Find the Concentration Where the External Solution and the Potato Are Isotonic

by Chloe Popov

SBI4U1-2 Mrs. Omand March 4, 2019

2 Introduction The purpose of this lab was to observe and analyze how the biological process known as osmosis effects the mass difference percentage of potato core samples when they are immersed in isotonic, hypotonic, and hypertonic sucrose solutions, with varying concentrations of sucrose. Immersing cells in said solutions allows for osmosis to occur. Osmosis is a form of passive transport where the solvent water molecules move from an area of high water concentration to an area of low water concentration across a semi-permeable cell membrane (Di Giuseppe, et al, 2003). Osmotic pressure is the pressure that results from a difference in solute concentration between the two sides of a selectively permeable membrane (Di Giuseppe, et al, 2003). A hypertonic solution is a solution where there are more solutes in the external solution and a lower concentration of water, causing a cell to lose water when immersed in this kind of solution (Di Giuseppe, et al, 2003). Plasmolysis, a hypertonic environment which occurs involving plant cells, is when there are less solutes and a higher concentration of water than that of outside of the cell, so water flows out of the cell, causing the cell membrane to shrink away from the cell wall, inevitably causing the cell to die (Plasmolysis, 2017). A hypotonic solution, an environment that is preferable for plant cells, is a solution that has less solutes than in the cell and a higher concentration of water than the cell, causing water to flow into the cell when immersed in this kind of solution (Di Giuseppe, et al, 2003). Turgor pressure, a hypotonic environment which occurs with plant cells, is when a cell has more solutes and a lower water concentration than that of outside of the cell, so water flows into the cell causing it to become turgid (Di Giuseppe, et al, 2003). An isotonic solution is a solution that has the same water and solute concentrations as the cell, meaning that the same amount of water flows in as out (Di Giuseppe, et al, 2003).

3 The percent mass difference of the potato core samples identifies if a sample has gained or lost water, through the biological process of osmosis, which would enable the ability to make estimate the concentration of sucrose within the potato core samples. A sample that was in a hypertonic solution should experience a decrease in mass, after being soaked in the solution. A sample that was in a hypotonic solution should experience an increase in mass, after being soaked in the solution. A sample that was in an isotonic solution should experience no change in mass, after being soaked in the solution. As the concentration of sucrose in the sucrose solution increases, the average percent mass difference should decrease, indicating that the potato core sample’s cells contained more water than the external solution, causing the water to flow out of its cells.

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4 References Di Giuseppe, M., Fraser, D., LeDrew, B., Vavitsas, A., & McMahon, M. (2003). Nelson biology 12. Toronto: Nelson Thomson Learning. Plasmolysis. (2017, September 10). Retrieved from https://www.biologyonline.org/dictionary/Plasmolysis...