This experiment was performed to investigate the selective permeability that dialysis tubing. The permeability the the tubing come glucose, starch and also iodine (potassium iodide) to be tested. The dialysis tubing was clipped to kind a bag so the glucose and also starch to be fed into the bag with the other end, and was also clipped to prevent the seeping of the solution.

Water with several drops the iodine added to it till it was visibly yellow-amber was included to a 400ml beaker. The bag was then put in the beaker, which to be stirred through a magnetic stirrer. It was left there because that 30 minutes. That was seen that the shade of the equipment in the bag readjusted to blue-black color, this confirmed that iodine had the ability to pass v the membrane right into the bag.

The systems in the beaker ended up being pale yellow-amber, this showed that strength didn’t pass v the membrane right into the beaker. To check the visibility of glucose in the manufacturer and also the bag, a Benedict test was performed ~ above the solutions consisting of tap water (control) too.

The beaker equipment turned right into light brown color after Benedict equipment was included to it and also suspended in water bath for 10 minutes. The bag systems also changed to brown color, if tap water continued to be blue. This experiment verified that dialysis tubing is selective in that is permeability to molecules. It to be permeable come glucose and iodine but not starch.

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PURPOSE: The purpose of the experiment to be to check the permeability of dialysis tubing to glucose, starch and iodine.


Living cells require to acquire nutrients from your environment and get rid the waste materials to their surroundings. This exchange of materials between the cell and also its next site is critical to that is existence. Cells have membranes composed of a phospholipid bilayer embedded with proteins.

This cell membrane deserve to distinguish between different substances, slow or hindering the activity of other substances and enabling others come pass v readily. This property of the cabinet is known as selective permeability (Ramlingam, 2008).

Selective permeability is a home of a cell membrane that permits it to control which molecules can pass (moving into and out that the cell) v the pores of the membrane. Selective permeable membranes only allows small molecules such together glucose, amino mountain to easily pass through, and inhibits larger molecules choose protein, starch, native passing v it.

The dialysis pipe is a semi-permeable membrane tubing supplied in separation techniques and demonstration the diffusion, osmosis, and movement the molecules throughout a limit membrane (Todd, 2012). That separates liquified substances of different molecular size in a solution, and some of the substances may readily pass v the pores the the membrane when others room excluded. The dialysis tubing is consisted of of cellulose fibers. This is shaped in a level tube.

In this experiment, the selective permeability of dialysis tubing come glucose, starch and also iodine (potassium iodide) will certainly be tested. This experiment consists of 2 tests; the test because that starch and also the test for reducing sugar. As soon as iodine (potassium iodide) is included to a equipment in which strength is present, the solution turns blue-black or violet otherwise it continues to be yellow-amber.

And once Benedict’s reagent is included to a equipment in i m sorry reducing sugar is present and it is cook in a water bath, the solution turns green, yellow, orange, red, and then brick red or brown (with high concentration of sugar present). Otherwise, the solution continues to be blue.


Will glucose, starch and iodine (potassium iodide) readily pass through the pores that the dialysis tubing?


Glucose, starch and iodine (potassium iodide) will readily pass through the membrane that the dialysis tubing.


The solution in the bag and the beaker will both turn blue-black due to the visibility of iodine and starch; the visibility of glucose in the bag and beaker will be investigated making use of Benedict test.

MATERIALS: BeakersDialysis TubingTest TubesClipsWater BathWater


Benedict’s reagentGlucoseStarchIodine (Potassium Iodide)


1) 250 ml of tap water was added to a beaker. Number of droppers the Iodine (Potassium Iodide) equipment was added to the water until it to be visibly yellow-amber in color. The color was climate recorded.

2) The dialysis tubing to be soaked in water for a few minutes until it started to open. One finish of the bag was folded and clipped in order to secure it so the no equipment seeped through.

3) The other finish of the tubing was opened so that it develops a bag and 4ml that glucose and 3ml of strength was fed right into it. The bag was additionally closed and its contents was mixed. The shade of the equipment was then recorded.

4) The outside of the bag to be rinsed in madness water.

5) The magnetic stirrer and then the bag was put in the beaker. The other end of the bag to be made come hang over the edge of the beaker.

6) The bag to be left in the maker for around 30 minutes, together the beaker was being stirred.

7) ~ 30 minutes, the bag was carefully removed and also made to stand in a dry beaker. The final shade of the solutions was recorded.

8) Benedict test was performed to test because that the existence of reducing sugar in the systems in the bag, beaker and tap water (serves together control).

a) 3 check tubes were labelled control, bag and beaker.b) 2 ml that water was added to the control test tube. 2 ml the the bag systems was added to the bag test tube and 2 ml that the beaker equipment was added to the beaker check tube.c) 2 ml of Benedict’s reagent was added to each test tube and also was suspended in a boiling water bath for 10 minutes. The color adjust was recorded.

The systems in the bag rotate blue-black in color owing to the movement of molecule of iodine native the beaker to the bag which contains starch. The solution in the beaker turned brown ~ Benedict’s test.

This indicated the existence of glucose in the beaker. This way that the tubing was permeable come both glucose and also iodine but not starch. It is known that starch didn’t pass because the equipment in the maker which consists of iodine didn’t revolve blue-black in color, yet remained yellow-amber.


1) How deserve to you define your results?

From the outcomes of the experiment stood for in a tabular kind above, the hypothesis argued before delivering out the experiment turned the end to it is in incorrect. The dialysis pipe was not permeable to every the three solutions- glucose, starch and Iodine (Potassium Iodide). Rather, the tubing was permeable come glucose and iodine but not starch.

This could be known from the color change in the services in the beaker and the bag. The tubing to be permeable to iodine and so the contents of the bag turn blue-black in color indicating the visibility of starch. Glucose likewise readily passed v the pores the the membrane.

After performing Benedict’s check on the solutions, the bag’s solution and also the beaker’s equipment turned brown in color. This reflects the presence of reducing street in both solutions, an interpretation that glucose passed into the beaker from the bag.


2) From your results, guess the dimension of Iodine (Potassium Iodide) relative to Starch.

From the results of this experiment, the is apparent that glucose and also iodine (potassium iodide) has actually smaller molecular size than starch. Due to the fact that starch had actually larger molecule size, the dialysis tube was no permeable to it (it didn’t permit it to readily pass through the pores that its membrane).

3) What colors would you mean if the experiment began with glucose and also iodine (potassium iodide) within the bag and also starch in the beaker? Explain

* The systems in the bag will remain yellow-amber in shade at the end of the experiment.

* The solution in the maker will rotate blue-black in shade at the end of the experiment.

* ~ performing benedict test, both remedies will revolve brown in color.

The equipment in the bag continued to be yellow-amber in color at the finish of the experiment due to the fact that the dialysis pipe is not permeable to starch and so strength didn’t pass v from the beaker into the bag.

The solution in the beaker turned blue-black in color at the end of the experiment because iodine passed native the bag right into the beaker through the membrane.

After performing Benedict’s check on the bag and also beaker solution, both solutions turned brown in color since the tubing was permeable to glucose, therefore glucose easily passed native the bag into the beaker v the membrane.


It was ensured that the right amount of solutions was provided in every part of the experiment.It was also ensured the the time compelled for the successful match of the experiment was adhered to.It was ensured the all apparatus used were taken on with caution.And also, the dialysis tubing to be clipped well on both ends to secure it so that no systems seeped through. CONCLUSION:

It to be concluded that the dialysis tube doesn’t permit all type of substances come pass easily through the pores that its membrane. This means that the is selective in that permeability to substances. The dialysis tubing was permeable come glucose and iodine however not come starch. Starch was excluded due to the fact that it has actually a bigger molecular size than glucose and iodine.


Ramlingam, S. T. (2008). Modern Biology. Onitsha: African very first Publishers.

Todd, I. S. (2012). Dialysis: History, advancement and Promise.

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