Osmosis and Selectively Permeable Membrane
Lab report OSMOSIS TROUGH A SELECTIVELY PERMEABLE MEMBRANE
Introduction: Molecules have kinetic energy. This causes the molecules of the cell to move around and bump into each other. Osmosis is a special kind of diffusion where water moves through a selectively permeable membrane (a membrane that only allows certain molecules to diffuse though). Diffusion or osmosis occurs until dynamic equilibrium has been reached. This is the point where the concentrations in both areas are equal and no net movement will occur from one area to another ( Reece, J. B, 2011, pp. 132-134).
Background:
1. Water potential is predicting the movement of water into or out of plant cells. Water always moves from an area of high to low water potential.
2. When the two solutions on either sides of the membrane are equal and no net movement is detected, the solutions are isotonic. This means that the solutions have the same concentration of solutes. If two solutions differ in the concentration of solutes that each has, the one with more solute is hypertonic. The solution that has less solute is hypotonic.
3. This experiment was performed to measure the osmosis of small molecules through cellulose bag (has the same structure that plant cell does). This tubing acts as a selectively permeable membrane, allowing larger molecules to pass through, but slowly. Dialysis is the movement of a solute through a selectively permeable membrane.
Purpose: To observe osmosis in a model membrane system.
Hypothesis: If I immerse in the beaker containing water one bag with distilled water and one bag with 40% maltose solution; and in the beaker containing 40% maltose solution – one bag with distilled water and one bag with 40% maltose solution, then osmosis will occur. I believe it will happen until dynamic equilibrium is reached.
Variables:
Independent Variable: Beaker with distilled water and beaker with 40% of maltose solution
Dependent Variable: Weight of the bag
Controlled
Introduction: Molecules have kinetic energy. This causes the molecules of the cell to move around and bump into each other. Osmosis is a special kind of diffusion where water moves through a selectively permeable membrane (a membrane that only allows certain molecules to diffuse though). Diffusion or osmosis occurs until dynamic equilibrium has been reached. This is the point where the concentrations in both areas are equal and no net movement will occur from one area to another ( Reece, J. B, 2011, pp. 132-134).
Background:
1. Water potential is predicting the movement of water into or out of plant cells. Water always moves from an area of high to low water potential.
2. When the two solutions on either sides of the membrane are equal and no net movement is detected, the solutions are isotonic. This means that the solutions have the same concentration of solutes. If two solutions differ in the concentration of solutes that each has, the one with more solute is hypertonic. The solution that has less solute is hypotonic.
3. This experiment was performed to measure the osmosis of small molecules through cellulose bag (has the same structure that plant cell does). This tubing acts as a selectively permeable membrane, allowing larger molecules to pass through, but slowly. Dialysis is the movement of a solute through a selectively permeable membrane.
Purpose: To observe osmosis in a model membrane system.
Hypothesis: If I immerse in the beaker containing water one bag with distilled water and one bag with 40% maltose solution; and in the beaker containing 40% maltose solution – one bag with distilled water and one bag with 40% maltose solution, then osmosis will occur. I believe it will happen until dynamic equilibrium is reached.
Variables:
Independent Variable: Beaker with distilled water and beaker with 40% of maltose solution
Dependent Variable: Weight of the bag
Controlled
References: Jayant, L., Meyers, O., Geddis, M., Priano, C. (2011). Laboratory manual for Biology I. Activity 4: Measurement of Temperature, pp 10-11 Reece, J. B., Urry, L. B., Cain, M. L., Wasserman, S. A., Minorsky, P. V., Jacksom, R. B. (2011). Campbell biology, Ninth Edition. San Francisco, CA. Chapter 3 Water and Life, pp 132-134.