Dialysis

Cell Transport: Dialysis of Methylene Blue, Calcium, and Chloride Ions By: Chelsea Caceres Caceres,, Nathalia Palma, Samantha Rillo, Diana Rondilla, and Angelica Velilia Velilia (Group 2)

ABSTRACT

The process of dialysis has an important role in order to maintain the functioning of cells. Because of this type of  passive transport, transport, transporting molecules through semi-permeable membrane is possible. possible. As not all substances substances can pass through the membrane, it is essential to determine the effect of the membrane’s membrane’s permeability in the transfer of different kinds of molecules and ions… The study’s objective. In this study, a simple set-up was used in order to test the presence of chloride and calcium ions in separate test tubes wherein aspirated 2-4 drops of calcium chloride solution and methylene blue was placed. The time when methylene  blue in the longganisa longganisa skin diffused was also recorded. recorded. At the end of the day, the study had proved that small molecules like chloride and calcium ions are allowed to pass in a differentially permeable membrane like the longganisa skin while preventing the passage of large molecules like methylene blue.

INTRODUCTION

Dialysis is the transfer of solutes across a semi-permeable membrane. In the cell, dialysis occurs by transporting molecules and ions through a semi-permeable cell membrane. It regulates its passage, allowing only small molecules and some ions into the cell, and prohibiting large molecules from passing through. With this, the cell can control its own composition, thus maintaining its constant condition. Furthermore, since this is a passive transport, it does not require energy. energy. Nowadays, dialysis is used to separate chemical components. This study aims to determine how the permeability of a membrane could affect the transfer of different kinds of molecules and ions, and which of these would diffuse first.

MATERIALS

1 beaker; 3 droppers; 3 test tubes; test tube holder; dried longganisa skin; rubber band; 3 ml calcium chloride; 2 ml methylene blue; 30 ml distilled water; diver nitrate; ammonium oxalate

METHODOLOGY

• 3 ml of Calcium Chloride solution and 2 ml of methylene blue was combined in a test tube.

• The said test tube was sealed with dried longganisa skin using a rubber band. • The test tube was immersed, with the sealed mouth facing down, in a beaker with 30 ml of distilled water using a test tube holder. • 2-3 drops of water was aspirated from the beaker and  placed it in 2 separate test tubes. •A dr op o f silver nitrate w a s

simultaneously added in the first test tube, and a drop of ammonium oxalate in the second. •Steps 3 and 4 were repeated very 30 seconds until precipitate formed in both test tubes. • The time when precipitate is observed in both test tubes was recorded whether methylene blue diffused into into the  beaker was noted.

RESULTS

Time (min)

Chloride Test

Calcium Test

Methylene Blue

Methylene Blue (Theoretic al)

Reactions Formed: Ag+  AgCl (precipitate) 2+ Ca  + C2O4 2- + CaC2O4 (precipitate)

Cl- +

!

1

-

-

-

-

2

-

-

-

-

3

-

-

-

-

4

-

-

-

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DISCUSSION

5

-

-

-

-

6

+

-

-

-

7

+

-

-

-

In both test tubes, cloudy white precipitate was observed. This shows the presence of chloride and calcium ions since they both reacted with their reactants, silver nitrate and ammonium oxalate respectively. Chloride ions diffused faster compared to calcium ions because they have a smaller molecular size or radius.

8

+

-

-

-

9

+

-

-

-

10

+

-

-

-

11

+

-

-

-

12

+

-

-

-

13

+

-

-

-

14

+

-

-

-

15

+

-

-

-

16

+

-

-

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CONCLUSION

17

+

+

-

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18

+

+

+

-

In dialysis, a differentially permeable membrane, such as a dried longganisa skin, allows the passage of small molecules, such as chloride and calcium ions, in which chloride ions diffuse faster, and prevents the passage of large molecules, such as methylene blue.

However, methylene blue is much larger in size. It is larger than the permeability of the dried longganisa skin can allow to pass through. Therefore, theoretically speaking, it should not have been able to diffuse into the beaker since its molecules cannot pass through. The dried longganisa skin is differentially permeable  because it allows the passage of small molecules, such as chloride and calcium ions, and prevents large molecules from  passing through, such as methylene blue.

Results of Dialysis of Methylene Blue, Calcium, and Chloride Test

Chloride Test

Calcium Test

REFERENCES: Books Agapito, J., Beltran, K., Endriga, M., Lapuz, R. S., Mazahery, A. R., Ng, J., Obico, J. J., Parungao, M., Ragragio, E., Rubite, R., Sia, A. J., & Yap, A. Biology 22: General Zoology Laboratory Manual Third Edition. Websites Dialysis. (2005). Retrieved November 23, 2013, from http://www.biology-online.org/dictionary/Dialysis Dialysis. (2013). Retrieved November 23, 2013, from http://encyclopedia2.thefreedictionary.com/Dialysis