Diffusion and Osmosis Lab

Diffusion and Osmosis are important to living organisms because water and certain solutes move in and out of cells by there two processes. However, molecules only move from region of high concentration to low concentration during these processes. Cells often need to absorb molecules from regions in which the concentration of the molecules may be lower than the concentration already inside the cell. The absorption of glucose from blood frequently occurs under these circumstances. Cells use the process of active transport to move substances through the cell membrane against a concentration gradient. Active transport involves proteins in the cell membrane against a concentration gradient. Active transport involves proteins in the cell membrane and energy derived from ATP. Diffusion of small molecules through a selectively permeable membrane (Tube). Tubing is made of a membrane containing tiny pores. The size of the minute pores in the tube determines the size of molecules that can pass through. Small solute molecules and water molecules can move through freely, but larger molecules will pass through more slowly, or perhaps not at all. The movement of a solute through a selectively permeable membrane is called dialysis.


This table will help you understand more of what went went on in the process.

Dialysis Tubing with carbohydrate solution and Water-Iodine Soultion

During this lab i filled a cup with a carbohydrate solution and a dialysis tube of water and iodine.
After 30 minutes of the tube sitting in the the water you could see a change in color and touch.

As you can see the color of the bag is a purple color that is because the water-iodine solution is starting to diffuse into the into the carb solution in the tube and the carb solution is starting to diffuse into the water-iodine solution.






After 24 hours of this lab the color changed completely and the mixtures were different.  We used carbohydrate testers and we found that both the tube and cup had traces of carbohydrate s inside them. As you can see the colors changed.

 

 

 

After 24 hours and I noticed the substance at the bottom i shook the tube and the purple substance mixed all together to create this.

These are my result questions:

1.) How would you explain the results you obtained? which substances(s) are entering the bag and which are leaving the bag? Support your answer with experimental evidence.

The results I obtained from this experiment is the starch water is still in the bag but the Iodine comes through the bag changing color in the cup.

2.) What evidence could have been collected to show quantitatively that water diffused in to the dialysis bag?

The iodine water is clear and the bag is purple. Also we tested both substances and the cup had carbohydrate traces in the water.

3.) What results would you expect if the experiment stated with glucose and IKI (iodine) solution inside the bag and only starch and water outside? Why?

It would be reversed the cup would be purple and the bag would be clear.