The Cell: Transport Mechanisms and Cell Permeability

Abstract

The purpose of this experiment is to investigate the process of diffusion and osmosis in non-living membrane. The process of diffusion and osmosis are very significant  and help in bodily function. For example: the diffusion of nutrients from blood into tissues. In this lab, experimental data is collected to analyze the effect of diffusion in non living membrane. The results is showed  that water molecule move from high to low concentration while solute act similar if the permeable membrane is present.

Introduction

1. In this lab, we are studied an overall effect various membrane on permeability. 
2. This is an interesting and important points, as we are studied the effect through the process of osmosis and diffusion.
3. According to the theoretical background of this experiment, there are two types of transport a) Active b) Passive. In active transport, the movement of the material occurs and the cell expands energy. In passive transport, the movement of substance occurs across the membrane in the absence of input energy by cell. Usually, in osmosis process movement of water occurs from three different areas .That solution will consider as the hypotonic to the cytosol in which the molecule present outside the cell are lower as compare to the concentration in cytosol. During that, water starts to diffuse into the cell membrane until the equilibrium state established. If the molecule present outside the cell is much higher as compare to the concentration in cytosol, the solution is considered as the hypertonic to cytosol .During that, water starts to diffuse outside the cell until equilibrium established. If the present of molecules at outside is same as the inside of the cell, the solution is isotonic.
4. In conclusion , the two hypothesis 1) “different solutes will diffuse based on temperature and permeability of membrane and  2) osmosis should occur based on the concentration on either side of membrane  ” are  tested.

Materials and Methods

Benedict’s solution , 10% NaCl, 3% AgNO3, De-ionized water,KMnO4, Weigh boats, Methylene Blue, Lugol’s Iodine, 20% Glucose, 250ml beaker, Green pipump, Wax pencil, Metric Ruler, Small culture Dishes, Test tube Clamps, Test tube.

In method section , four dialysis sacs are used. Solution : Sac 1, 20 ml of 40% glucose solution, Sac 2, 20 ml of 40% glucose solution, Sac 3, 20 ml of 10% NaCl solution, Sac 4, 20 ml of 40% sucrose solution containing Congo red dye are weighted and placed in beaker. Remain beaker undisturbed for about 1 hour. And boil the water beaker for AgNO3 and Benedict’s test. Dialysis sacs are taken and blotted gently then weighted and collected data ("Cell Transport Mechanisms And Permeability").

 

Results

In results, dye diffusion and experimental data of diffusion and osmosis through non living membrane are tested. 

1. Dye Diffusion Result

Potassium dye diffuse rapidly.

 

1. Experimental Data Result on diffusion and osmosis through non living membrane

Cloudy white milk appears that indicates the presence of silver chloride AgCl. AgCl is formed due to the reaction in between sodium chloride NaCl and silver nitrate AgNO3.

Discussion

The experimental results are confirmed the hypothesis that diffusion  is supposed to occur at faster rate with high temperature and the molecule that have smaller molecular weight is diffused faster. The section of testing the permeability of membrane is indicated  the dialysis tube is completely permeable to the iodine and the content is turned into black color as because iodine is diffused through reacting with sucrose Furthermore, membrane is also permeable to the glucose as because Benedict’s test is positive, which is indicated the sugar. This is implied that glucose is diffused into iodine and water solution. The solutes are hypertonic and are expected to diffuse with solution. The chemicals present in the solution are hypertonic .All these observations are confirmed the hypothesis that the iodine and water can move while the starch cannot move. Furthermore, the movement of glucose molecules is also observed.

Compare dialysis, diffusion, and osmosis