A selectively permeable membrane allows some types of molecules and ions to pass through, but not others. In contrast, glucose, iodine, and water molecules are small enough to pass through the membrane. Diffusion results from the random motion of molecules. Show Why does iodine move into the bag? The iodine moved into the bag, because the cornstarch inside the bag changed color, but the iodine solution outside the bag did not change color. 2. Define “selectively permeable.” Selectively permeable means that a membrane allows only certain substances to pass through it; the cell membrane is selectively permeable. What do you think will happen with the beaker and the bag?the bag in which beaker will experience a rise in osmotic pressure? that is has absorbed that water from the beaker, in other words, a hypotonic experiment has occurred. a cell takes in two substances (A and B) which are present in lower concentrations outside the cell than inside of it. What happens when iodine comes in contact with starch? Amylose in starch is responsible for the formation of a deep blue color in the presence of iodine. The iodine molecule slips inside of the amylose coil. This makes a linear triiodide ion complex with is soluble that slips into the coil of the starch causing an intense blue-black color. Why didn’t the starch enter the beaker?It is known that starch didn’t pass because the solution in the beaker which contains iodine didn’t turn blue-black in color, but remained yellow-amber. How does iodine enter the cell? The iodide within the follicular cell moves towards the apical surface of the plasma membrane, to enter into the follicular lumen; this transport by a sodium independent iodide/chloride transporter called pendrin. What color is the iodine water mixture in the beaker before the demonstration?Place the baggie in the cup so that the cornstarch mixture is submerged in the iodine water mixture….Data Table.
What was inside the bag and what was inside the beaker? Starch and glucose were in the bag and the beaker was filled with iodine. Starch is too big of a molecule to diffuse out of the bag, the iodine was small enough to diffuse into the bag, and the sucrose was small enough to diffuse into the beaker. What happens when iodine is added to water?When iodine solution were added to rice water, the solution turned blue black because of the presence of starch. When iodine comes in contact with starch, it forms starch Iodide complex because iodine gets stuck in the beta coils in the structure of amylose of starch. The starch iodide complex gives blue-black colour. What’s the best way to experiment with iodine and starch? Method When doing this experiment, you can let the kids decide how to approach it. They may choose to place the iodine in the dialyses tubing and starch in the beaker or Vise Versa. In this experiment I will be doing starch in the Dialyses tubing and Iodine in the beaker. What happens if you put iodine in a diffusion bag?If the iodine solution penetrates the bag, it will turn the starch solution inside the baggie, purple. The control data chart above shows that if the starch had not been immersed in the iodine solution, but rather a water solution, it would have remained the same color, white. What happened to the iodine in the diffusion bag? How are iodine molecules diffused into a tube? Iodine molecules are small enough to pass freely through the membrane, however starch molecules are complex and too large to pass through the membrane. Initially there was a higher concentration of iodine outside than inside the tube. Thus iodine diffused into the tube with the starch. Related
NAME:DIFFUSIONANDOSMOSIS-LABREPORTSHEETExercise 1 – DiffusionAnalysis:1. Record your hypothesis here: Get answer to your question and much more 2. Record your prediction here: Get answer to your question and much more Table 1: Diffusion of starch through a semipermeable membrane1.Why did the corn starch change colors?Was your hypothesis supported or rejected?Why or why not? Get answer to your question and much more 2.Define permeability. To which substance is the plastic bag permeable? Get answer to your question and much more Upload your study docs or become a Course Hero member to access this document Upload your study docs or become a Course Hero member to access this document End of preview. Want to read all 4 pages? Upload your study docs or become a Course Hero member to access this document
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Why didnt the starch enter the beaker?
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