have Cells kinetic energy. T his causes the molecules of the cell to move around and bump i nto each other. D iffusion is one result of this molecular movement. D iffusion is the r andom movement of molecules from an areasdf5a of higher concentration to areas of lower concentration. Osmosis is a special kind of diffusion where asdasdas water moves through a selectively permeable membrane (a membrane that only allows certain molecules to d iffuse though). D iffusion or osmosis occurs until dynamic equilibrium has been reached. T his is the point where the concentrations in both areas are equal and no net movement w ill occur from one area to another. I f two solutions have the same solute concentration, the solutions are said to be isotonic. I f t he solutions differ in concentration, the area with the higher solute concentration is hypertonic and the area with the lower solute concentration is hypotonic. Since a hypotonic solution contains a higher level of solute, it has a high solute potential and low water potential. T his is because water potential and solute potential are inversely proportional. A hypotonic solution would have a high water potential and a low solute potential. A n isotonic solution would have equal solute and water potentials. Water potential () is composed of two main things, a physical pressure component, pressure potential (p), and t he effects of solutes, solute potential (s). A formula to show this relationship is = p + s. Water will always move from areas of high water potential to areas of low water potential. The force of water in a cell against i ts plasma membrane causes the cell to have turgor p ressure, which helps maintain the shape of the cell. W hen water moves out of a cell, the cell will loose turgor pressure along with water potential. T urgor pressure of a plant cell is usually attained while in a hypotonic solution. T he loss of water and turgor pressure while a cell is in a hypertonic solution is called plasmolysis. Hypothesis: D uring these experiments, i t will be proven that diffusion and osmosis occur between solutions of different concentrations until dynamic equilibrium is reached, affecting the cell by causing plasmolysis or increased turgor pressure during the process. M ate rials: L ab 1A - To begin 1A, Lab fi rst collect the desired equipment. T he materials needed are d ialysis tubing, Iodine Potassium Iodide (IK I) solution, 15% glucose/ 1% starch solution, g lucose Testape or Lugols solution, distilled water, and a 250-mL beaker. Lab 1B - For Lab 1B you will need to collect six presoaked dialysis tubing strips, distilled water; 0.2M, 0.4M, 0.6M, 0.8M, and a 1.0M sucrose solution; six 250-mL beakers or cups,
and a scale. Lab 1C - L ab 1C these i tems are needed: a potato, knife, potato core borers, six different solutions, and a scale. Lab 1D - D uring Lab 1D, only paper, pencil, and a calculator will be needed to make the calculations. Lab 1E - n L ab 1E these i tems are needed: a microscope slide, cover slip, onion cells, light m icroscope, and a 15% NaCl solution. P rocedures: Lab 1A - A fter gathering the materials, pour glucose/starch solution into dialysis tubing and close the bag. Test the solution for presence of glucose. Test the beaker of distilled water and I K I for presence of glucose. Put the dialysis bag into the beaker and let stand for 30 minutes. W hen t ime is up test both the bag and the beaker for presence of glucose. Record all data in table. Lab 1B - Obtain the six strips of dialysis tubing and fill each with a solution of a different molarity. M ass each bag. Put each bag into a beaker of distilled water and let stand for half and hour. A fter 30 minutes is up, remove each bag and determine i ts mass. Record all data in its appropriate table. Lab 1C - sing the potato core borer, obtain 24 cylindrical slices of potato, four for each cup. Determine the mass of the four cylinders. I mmerse four cylinders into each of the six beakers or cups. Let stand overnight. A fter t ime is up, remove the cores from the sucrose solutions and mass them. Record all data in its appropriate table. Lab 1D - Using the paper, pencil, and calculator collected, determine solute potentials of the solutions and answer the questions asked to better understand this particular part of the l ab. Lab 1E - Using the materials gathers, prepare a wet mount slide of the epidermis of an onion. D raw what you see of the onion cell under the microscope. A dd several drops of the NaCl solution to the slide. Now draw the appearance of the cell. D ata: