Bio 151/Mrs. Eischen
Diffusion is the transfer of molecules back and forth across a membrane, Osmosis is the act of water diffusion. They are important factors in the maintenance of a cells life by allowing the cell to import/export nutrients and water passively without expending unnecessary energy. The water and solute concentration gradient of the surrounding environment and the interior of the cell plays a crucial role in the effects of diffusion, as higher concentrations of molecules tend to move towards lower areas of concentration as the molecules bump into each other and sub-sequentially spread out. This experiment will involve the use of dialysis tubing to mimic a cell body and reflect the permeability of its membrane, then staging the cells containing various degrees of solution percentage of distilled water and glucose into environments of distilled water. As the tonicity of the cell increases, the high concentration of water outside the cell will diffuse to the low water concentrated interior of the cell based on its percentage of solutes.
Experiment 1 Methods
Filled four glass environments with 100ml distilled water then labeled each with proper percentage notation of the containing cells (0%, 10%, 25%, 50% glucose solutions in experiment 1) (0%, .5%, .75%, 1% albumin solution in experiment 2). Placed 3 drops of each environments water in experiment one into test tubes then added 3 drops benedicts to test for contaminants. Placed 3 drops of each environments water into a tube then added 3 drops bieuret to test for contaminants in experiment 2. Opened 4 dialysis tubes and filled with the proper amounts of solution. Cell 1 contained 10ml 100% distilled water. Cell 2 contained a .5% solution of 50ml water and 50ml 1% albumin. Cell 3 contained a 10ml .75% solution of 2.5ml water and 7.5ml 1% albumin. Cell 4 contained a 10ml 1% solution of 10ml 1% albumin. Weighed each cell on a scale measured in grams before placing in water. After being placed in water for five minutes, extracted each cell for weighing. Repeated 5 more times. At end of time cycle, added ten drops of bieuret to each environment in experiment two to test for presence of protein, and then placed 3 drops from each environment in experiment one to separate tubes then placed 3 drops benedicts to each to test the presence of sugar.
The 50% glucose cell in experiment 1 gained an overall mass of 3.77 grams during the course