This experiment was conducted to inspection the selective permeability that dialysis tubing. The permeability that the tubing come glucose, starch and iodine (potassium iodide) was tested. The dialysis tubing to be clipped to type a bag so the glucose and starch to be fed into the bag with the other end, and also was likewise clipped to protect against the seeping the the solution.

Water with several drops that iodine added to it until it was visibly yellow-amber was included to a 400ml beaker. The bag was then put in the beaker, which was stirred with a magnetic stirrer. It to be left there because that 30 minutes. It was watched that the shade of the solution in the bag changed to blue-black color, this proved that iodine was able to pass v the membrane into the bag.

The equipment in the beaker ended up being pale yellow-amber, this proved that starch didn’t pass through the membrane right into the beaker. To confirm the existence of glucose in the beaker and also the bag, a Benedict test was performed ~ above the solutions including tap water (control) too.

The beaker systems turned right into light brown color after Benedict solution was included to it and also suspended in water bath for 10 minutes. The bag solution also adjusted to brown color, while tap water remained blue. This experiment verified that dialysis pipe is selective in that is permeability to molecules. It was permeable come glucose and iodine yet not starch.

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PURPOSE: The function of the experiment to be to test the permeability that dialysis tubing come glucose, starch and also iodine.


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

This cabinet membrane have the right to distinguish between different substances, slowing or hindering the motion of other substances and permitting others come pass v readily. This property of the cabinet is well-known as selective permeability (Ramlingam, 2008).

Selective permeability is a residential or commercial property of a cabinet membrane that allows it to control which molecules can pass (moving into and out that the cell) with the pores that the membrane. Selective permeable membranes only allows small molecules such together glucose, amino acids to conveniently pass through, and inhibits bigger molecules favor protein, starch, native passing v it.

The dialysis tube is a semi-permeable membrane tubing offered in separation techniques and demonstration that diffusion, osmosis, and also movement that molecules across a limit membrane (Todd, 2012). The separates dissolved substances of different molecular size in a solution, and also some that the substances might readily pass through the pores of the membrane if others space excluded. The dialysis pipe is made up of cellulose fibers. This is shame in a flat tube.

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

And as soon as Benedict’s reagent is added to a solution in i beg your pardon reducing sugar is present and it is heated in a water bath, the equipment turns green, yellow, orange, red, and also then brick red or brown (with high concentration of sugar present). Otherwise, the solution remains blue.


Will glucose, starch and also iodine (potassium iodide) conveniently pass with the pores of the dialysis tubing?


Glucose, starch and also iodine (potassium iodide) will readily pass v the membrane of the dialysis tubing.


The equipment in the bag and the beaker will both revolve blue-black because of the existence of iodine and also starch; the presence of glucose in the bag and also beaker will certainly be investigated utilizing Benedict test.

MATERIALS: BeakersDialysis TubingTest TubesClipsWater BathWater


Benedict’s reagentGlucoseStarchIodine (Potassium Iodide)


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

2) The dialysis tubing to be soaked in water because that a few minutes until it began to open. One end of the bag to be folded and clipped in order to secure that so the no systems seeped through.

3) The other finish of the tubing was opened up so the it develops a bag and also 4ml of glucose and 3ml of strength was fed into it. The bag was likewise closed and its contents was mixed. The shade of the solution was then recorded.

4) The external of the bag was rinsed in tap water.

5) The magnetic stirrer and then the bag was placed in the beaker. The other finish of the bag was made come hang over the leaf of the beaker.

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

7) after ~ 30 minutes, the bag was closely removed and also made to was standing in a dry beaker. The final color of the options was recorded.

8) Benedict test was performed come test for the visibility of reducing street in the solution in the bag, beaker and tap water (serves together control).

a) 3 test tubes were labelled control, bag and also beaker.b) 2 ml the water was added to the control test tube. 2 ml the the bag solution was added to the bag test tube and also 2 ml the the beaker solution was added to the beaker check tube.c) 2 ml that Benedict’s reagent was included to each test tube and also was rely in a boiling water bath because that 10 minutes. The color readjust was recorded.

The solution in the bag turn blue-black in color owing come the movement of molecules of iodine indigenous the beaker come the bag which consists of starch. The solution in the beaker turn brown after Benedict’s test.

This suggested the existence of glucose in the beaker. This means that the tubing was permeable to both glucose and also iodine however not starch. The is recognized that strength didn’t pass due to the fact that the systems in the maker which consists of iodine didn’t revolve blue-black in color, but remained yellow-amber.


1) How deserve to you explain your results?

From the results of the experiment represented in a tabular kind above, the hypothesis suggested before transferring out the experiment turned the end to be incorrect. The dialysis tubing was no permeable to every the 3 solutions- glucose, starch and Iodine (Potassium Iodide). Rather, the tubing was permeable come glucose and also iodine yet not starch.

This can be well-known from the color readjust in the solutions in the beaker and also the bag. The tubing was permeable to iodine and also so the contents of the bag rotate blue-black in color indicating the visibility of starch. Glucose also readily passed v the pores the the membrane.

After performing Benedict’s test on the solutions, the bag’s solution and also the beaker’s equipment turned brown in color. This reflects the visibility of reducing street in both solutions, meaning that glucose passed right into the beaker native the bag.


2) From your results, predict the size of Iodine (Potassium Iodide) family member to Starch.

From the outcomes of this experiment, that is obvious that glucose and also iodine (potassium iodide) has smaller molecular size than starch. Since starch had actually larger molecular size, the dialysis pipe was no permeable to it (it didn’t allow it to easily pass with the pores that its membrane).

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

* The solution in the bag will stay yellow-amber in color at the end of the experiment.

* The equipment in the beaker will rotate blue-black in shade at the finish of the experiment.

* ~ performing benedict test, both options will turn brown in color.

The solution in the bag stayed yellow-amber in shade at the finish of the experiment due to the fact that the dialysis tubing is no permeable to starch and so starch didn’t pass v from the beaker right into the bag.

The solution in the beaker turn blue-black in shade at the finish of the experiment since iodine passed indigenous the bag right into the beaker v the membrane.

After performing Benedict’s check on the bag and beaker solution, both services turned brown in color since the tubing was permeable come glucose, therefore glucose conveniently passed from the bag right into the beaker through the membrane.


It was ensured that the right quantity of services was offered in every component of the experiment.It was additionally ensured that the time forced for the successful match of the experiment was adhered to.It was ensured the all apparatus supplied were taken on with caution.And also, the dialysis tubing was clipped fine on both ends to secure that so the no systems seeped through. CONCLUSION:

It was concluded that the dialysis pipe doesn’t permit all type of substances to pass conveniently through the pores that its membrane. This method that the is selective in its permeability to substances. The dialysis tubing to be permeable come glucose and iodine yet not come starch. Strength was excluded due to the fact that it has a larger molecular dimension than glucose and iodine.


Ramlingam, S. T. (2008). Modern Biology. Onitsha: African an initial Publishers.

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

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