I. In a brief paragraph, interpret your experimental observations and the experiment of another group, keeping in mind the key concepts of semipermeable membrane, large molecules, and small molecules. Our group mixed the blue dextran with the vitamin B12 and the content was a dark purple color. The next day, I observed that the water was a reddish color and inside of the dialysis bag was blue. This showed the semipermeable membrane process. At equilibrium, the small molecules could pass through while the larger ones remained in the bag. The other group mixed starch and iodine in the bag. The initial color observed was dark blue. When I went back the next day, I saw no change; the solution in the dialysis bag was still dark blue and the …show more content…
How do the results you have observed with blue dextran and vitamin B12 show that your dialysis tubing is “semi-permeable”? The results showed that my tube was semi-permeable because the vitamin B12 (red) was outside of the dialysis bag and the blue dextran stayed inside. This shows semi-permeable because the smaller molecules could escape while the macromolecules stayed within. 2) If dialysis tubing containing water was placed into a beaker filled with a solution of vitamin B12, describe carefully what you would expect to happen and what you would see in terms of the colors of the contents of the tubing and the solution in the beaker. I would expect to see the vitamin B (red) to diffuse in an area of high concentration to an area of low concentration until equilibrium is reached. So, the tube will contain both water and vitamin B12. 3) Starch is a large polymer. A concentrated solution of starch is a milky white color. Iodine consists of small molecules and a solution of it is orange. When iodine is in contact with starch, it binds to the starch creating a dark blue colored complex. Describe what you would expect to occur if you placed starch solution inside a dialysis bag and placed the bag in a beaker full of iodine