General Biology: Critical Thinking Activity 
General Biology I Lab (Bio 104)
CRITICAL THINKING ACTIVITY I – Diffusion/Osmosis
Name: Tonya Finch
What are the 2 tests substances?
1. Potato starch
2. Sugar Water
3. Why did a color change occur in the jar water? Because IKI was added to give it an amber color (gold color). It iodine solution and this caused the color change.
4. What does the color change in #3 indicate? Water and IKI was in jar and the iodine caused the color change of the water.
5. Why did a color change occur in the dialysis tubing bag? In the bag there was water, sugar (glucose) and starch. When IKI (iodine) comes into contact with the starch the contents in the bag turned blue. This IKI was able to make its way into the dialysis tubing therefore they contact because the IKI molecules are smaller than the holes in the tubing through the process of diffusion.
6. What does the color change in #5 indicate? It indicates that the diffusion process is taking place and the molecules are moving a higher concentration to a lower concentration. The blue color is evident that there is movement of molecules.
7. What does the Benedict’s reagent test detect? It is a test performed to test the reduction of sugars such as monosaccharide’s and disaccharides.
8. What does the test of the jar water indicate? That the starch molecules in the dialysis tubing are larger than the in the tubing therefore they cannot be transferred through the process of osmosis or diffusion.
9. What substance did not seem to diffuse across the dialysis tubing membrane? The starch did not move from a high concentration to a lower concentration because the starch molecules were too large to diffuse through the dialysis tubing.
10. Why did you answer #9 as you did? Because diffusion is the movement of molecules forms a high concentration to a lower concentration. For example, IKI was in the water, but the water did not turn blue because there was presence of starch in the water. IKI and starch
CRITICAL THINKING ACTIVITY I – Diffusion/Osmosis
Name: Tonya Finch
What are the 2 tests substances?
1. Potato starch
2. Sugar Water
3. Why did a color change occur in the jar water? Because IKI was added to give it an amber color (gold color). It iodine solution and this caused the color change.
4. What does the color change in #3 indicate? Water and IKI was in jar and the iodine caused the color change of the water.
5. Why did a color change occur in the dialysis tubing bag? In the bag there was water, sugar (glucose) and starch. When IKI (iodine) comes into contact with the starch the contents in the bag turned blue. This IKI was able to make its way into the dialysis tubing therefore they contact because the IKI molecules are smaller than the holes in the tubing through the process of diffusion.
6. What does the color change in #5 indicate? It indicates that the diffusion process is taking place and the molecules are moving a higher concentration to a lower concentration. The blue color is evident that there is movement of molecules.
7. What does the Benedict’s reagent test detect? It is a test performed to test the reduction of sugars such as monosaccharide’s and disaccharides.
8. What does the test of the jar water indicate? That the starch molecules in the dialysis tubing are larger than the in the tubing therefore they cannot be transferred through the process of osmosis or diffusion.
9. What substance did not seem to diffuse across the dialysis tubing membrane? The starch did not move from a high concentration to a lower concentration because the starch molecules were too large to diffuse through the dialysis tubing.
10. Why did you answer #9 as you did? Because diffusion is the movement of molecules forms a high concentration to a lower concentration. For example, IKI was in the water, but the water did not turn blue because there was presence of starch in the water. IKI and starch