Abstract: In this lab students tested three different hypothesis.In the first the students tested the diffusion of deionized water into a glucose starch solution filled dialysis bag inorder to understand the concept of diffusion. The second experiment consisted of the students weighing deionized water filled dialysis bags before and after placing them inside of sucrose solution filled cups in order to better understand osmosis. The final experiment was based off of water potential where the students weighed potatoes and placed them in a sucrose solution to determine which had a higher and lower water potential. Introduction:The membrane around a cell helps to protect the internal parts of the cell due to its semipermeable traits. A semipermeable membrane only allows certain molecules to pass through using facilitated diffusion and active transport. Diffusion is thenet movement of a substance from a higher concentration to a lower concentration.This occurs because molecules in solutions or cells are constantly moving and collide with each other, when they collide some molecules will move to a lower concentrated area inorder to reach an equilibrium. Even after they reach an equilibrium the molecules will remain moving. This lab’s purpose is to observe, measure, and compare the diffusion ofwater, starch and glucose through both artificial and natural membranes. After the completion of this lab students will be able to measure a solution’s water potential in a controlled experiment. In order to determine solute potential the student will use the following equation: ΨS = -iCRT. The student will become familiar with the concepts of concentration gradient, osmosis, selectively permeable membrane, diffusion, and plasmolysis.Hypothesis: Activity 1: If a dialysis bag filled with15mL of a glucose-starch solution is placed inside of a 9 oz cup filled with deionized water then diffusion will occur and iodine will seep through the bag’s semipermeable membrane. Activity 2: If different moles of sucrose solution are put into six different cups and deionized water filled dialysis bags are placed into the cups then the mass of the bag will increase more in the higher concentrated cups than in the lower sucrose solution concentrations.Activity 3: If four potato slices are placed in cups of differently concentrated sucrose solution filled cups then the potatoes’ mass will decrease overnight. Materials & Procedures: Activity 1:●15% Glucose- 1% Starch solution, 16mL●Iodine solution, 4mL●Water, deionized, 100mL●Cup, plastic, 9 oz.
●Dialysis tubing, presoaked, 20cm●Dialysis tubing clamps, disposable, 2●Funnel, plastic●Glucose test strips,4●Graduated cylinder, 25-mL●Marker or wax pencil●Paper, white●Pipet, graduated,6 ●Weighing dish, smallActivity 1 Procedure:1.Obtain 1ml of the glucose-starch solution in a graduated pipet.