Diffusion and Osmosis Using “Deshelled” Chicken Eggs

Diffusion and Osmosis Using “Deshelled” Chicken Eggs

Introduction

With the various change in the extracellular environment, cells and tissues are subjected to various conditions, which may cause stress to the body. For the body to maintain a harmonic balance of its internal environment, it has to make use of the forces of diffusion and osmosis. The process of osmosis enables living tissues to maintain a pressure balance between the internal and external environment of the cell (Strange, 2004). It also enables the cells to absorb nutrients as well as expel the waste material from different organs.

Diffusion is generally the phenomenon in which molecules of high concentration move to regions where they are less concentrated until equilibrium is achieved. The diffusion can either be simple diffusion, which does not require a membrane or facilitated diffusion, which requires a protein carrier to pass through the bipolar membrane.in the case of diffusion, it is the solute molecules that move against the concentration gradient (Meschia, & Setnikar, 2007). However, in osmosis, solvent/water molecules move from the region where they are highly concentrated into the region of their lower concentration. A semi-permeable membrane facilitates this process. The movement of water molecules during osmosis is dependent on the concentration of the cell’s surroundings (VanSomeren, 2011). The surroundings can be isotonic, hypertonic, or hypotonic and create a concentration gradient between the cell and its environment.

A hypertonic solution contains more of the solute molecules as opposed to water molecules. If a cell is subjected to such an environment, the osmotic pressure created between the two regions will cause the water molecules to diffuse out of the cell, where they are highly concentrated into the solution where they are less concentrated. This activity may affect the cell shape causing it to shrink (VanSomeren, 2011).  An isotonic environment contains an equal balance of solute concentration with the cell. As such, a concentration gradient cannot be created, and thus the net osmosis would be zero. In the case of a hypotonic solution, water molecules diffuse from the solution where they are highly concentrated into the cell. This may affect cells causing them to swell and can finally lead to cytolysis in cells that lack a cell wall.

Experimental Objectives

The experiment was to demonstrate the effect of osmosis on living cells under different conditions of tonicity using unshelled chicken eggs. It was hypothesized that egg 1 in the hypotonic solution (0% sucrose) would swell and increase in weight. Egg 2 in the 14% sucrose solution (isotonic) would not change, while egg 3 in the 40% sucrose would shrink and reduce in weight.

Materials and Method

• 3 unshelled Eggs (treated with dilute acetic acid)
• 3 Glass culture Dishes
• 3 Sucrose bathing solutions (0%, 14%, 40%)
• Spoon
• Paper Towels
• Balance
• Large Weigh Boats

Procedure

Protective hand gloves were worn throughout the experimental procedure. The materials were brought from the course set are into the experimental table. After gently blotting, the eggs were measured separately to the nearest 0.1g, and the data recorded in table 1 at time 0. Eggs 1, 2, and 3 were placed each in a separate culture dish containing solutions of distilled water (0% sucrose), 14% sucrose, and 40% sucrose. The weight of the eggs was determined at a time interval of 15 minutes up to the 60^th minute by carefully removing them from the solution, wiping them dry, and weighing them separately. The data was recorded in table 1. The eggs were then replaced in the dish for the next interval. The eggs were returned into their container, and each solution to its labeled container after the experiment was complete. The dishes and experimental table were then cleaned, and the weigh boats and all other material returned to the setup area.

Results

Table 1   Weight of Eggs (g) vs. Time (minutes)

Following the hypothesis, the egg in distilled water (0% sucrose) swelled and increased in weight. The starting mass of the egg at 0 minutes was 67 grams and increased to 70 grams at the end of 60 minutes. The egg in the 14 % (isotonic solution) had no change. Its starting mass was 77 grams at zero minutes and 77 grams at the 60^th minute. That in the 40 % sucrose solution (hypertonic solution) decreased in weight. It had a starting mass of 82 grams at time zero and 78 grams after 60 minutes.

Table 2 Weight Change of Eggs (g) vs. Time (minutes)

Table 3 Total Weight Change of Eggs (g) vs. Sucrose Concentration (%

The egg in 0% sucrose solution had lost a total of 3 grams that in the 14% sucrose had lost 0 grams while that one in the 40% sucrose solution lost a total of 4 grams at the end of the 60-minute experimental period. This information was further interpreted by the use of graphs as shown below

Figure 1 showing a graph of weight change in eggs in grans against time in minutes

Figure 2 showing a graph of total weight change of eggs in grams against the concentration of sucrose

Discussion

An unshelled egg functions in a similar way just living cells. It can allow the entry and exit of cellular components in and out of the cell. In this experimental test, it was hypothesized that the egg which was placed in distilled water would swell and increase in weight. Through the experimental results, the egg in the hypotonic solution gained weight with time. The egg absorbed water by osmosis since its cellular components were highly concentrated as compared to the solution the egg was placed in. Water molecules, therefore, diffused into the egg to bring a balance between the two regions (Lucké, Hartline, & McCutcheon, 2010). It was thus concluded that cells in a hypotonic environment will gain water swell and may, at times, lyse.

The egg in the isotonic solution did not have any change. Its weight remained the same, even as time increased. The concentration of the egg and the 14% sucrose solution were equal. As such, there was no concentrating gradient that existed between the egg cellular components and the sucrose solution. As such, there was no notable increase in weight. Finally, it had been hypothesized that the egg in the 40% sucrose solution would reduce in weight. During the experiment, this egg continually lost weight as time increased. 40% sucrose solution is highly concentrated compared to the egg cells. In this case, the solution extracted water molecules from the egg cell, causing it to shrink and lose weight. More water was lost with an increase in time.  From the resulted obtained, all the test hypotheses were accepted.

Applications of Osmosis

Osmosis is widely used by living cells in the regulation and maintenance of a harmonic balance of the cells and their external environment. It is also applied in the absorption of nutrients as well as the excretion of toxic waste products from different body organs.

Conclusion

Osmosis is a vital process in the normal functioning of cellular organs in all living things. The effect of concentration on living cells can be determined using living cells such as the unshelled egg to explain how the process happens within our body. Osmosis in cells is highly affected by the concentration of the surrounding solution. A hypotonic environment would cause cells to absorb water from the environment while a hypertonic environment will draw water from the cells. An isotonic environment has no impact on osmosis since it does not create a concentration gradient between the two regions.

References

Lucké, B., Hartline, H. K., & McCutcheon, M. (2010). Further studies on the kinetics of osmosis in living cells. The Journal of general physiology, 14(3), 405-419.

VanSomeren, L. (2011). Fun Science Experiment – Dissolve an Egg Shell. Retrieved from https://untamedscience.com/biology/cells/osmosis/

Meschia, G., & Setnikar, I. (2007). Experimental study of osmosis through a collodion membrane. The Journal of general physiology, 42(2), 429-444.

Strange, K. (2004). Cellular volume homeostasis. Advances in physiology education, 28(4), 155-159.