Cell membranes are a bilayer make up of phospholipids, proteins, and cholesterol. Its main function is to regulate what comes in and out of the cell by means of diffusion, transport proteins and protein channels. Trans membrane proteins transport polar solutes across hydrophobic regions of the bilayer. Diffusion occurs when solutes are transferred from a high concentration of that solute to a lower concentration of solutes. Solutes do not depend on the concentration of other solutes, which allows the cell to take in oxygen while releasing carbon dioxide. Osmosis is a special type of diffusion, which occurs when water is diffused across the membrane. This can be affected by how hydrophilic a solute is on either side of the membrane. The diffusion of glucose, starch, and iodine was observed when the solutes went from a higher concentration of their individual solute to a lower concentration diffusing threw pores in the dialysis bag. The experiment sought to find out which solutes would diffuse threw the pores of the dialysis bag, whether in or out of the bag. The pores and walls of the dialysis bag acted as a permeable membrane, like the one found in cells, and was the regulator of diffusion for the solutes. Studying the movement of solutes threw the dialysis bag helps better understand diffusion of a cell membrane, and the means and solutes that make a solution isotonic. If the iodine concentration is higher outside the dialysis bag of starch and glucose than in it, iodine along with water will diffuse into the bag while the starch remains in the dialysis bag and some glucose will diffuse out of the dialysis bag.
| Solute Concentration (M)
| Tonicity (i.e. hypotonic)
| Expected mass change (+ or -)
| 0.058 M
| 0.134 M
| .000385 M
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