Egg Diffusion Lab

       In this experiment, we took two regular eggs and submerged them in vinegar for two days to dissolve their hard outer shell. We then placed them in water for two more days. After this process, we took two egg cells and placed one in a sugar solution, and the other in water. Our group was responsible for measuring the egg immersed in the sugar solution. We measured the circumference and mass of the egg before and after it was soaked in its solution, recorded the data, and were able to understand and reason as to why we got the results we did. As the sugar concentration increased, the mass and circumference decreased. The reason the egg shrank was because the situation was hypertonic. What hypertonic means is that there was more solute (sugar molecules) outside of the cell than inside the cell. Because the solute was too large to enter the egg cell through its membrane, the solvent (water) had to move outside the cell in order to stabilize the amount of molecules inside and out of the cell. Because the egg cell has lost its solvent, this causes it to shrink. Below is the egg cell before it has been placed in the sugar solution (left egg), and the egg cell after it has been in the sugar solution for two days (right egg).

        The sugar solution clearly caused the egg to shrink because of the amount of solute and solvent in and outside the cell, but this process is called diffusion. Diffusion is when small molecules move from an are of high concentration to an area of low concentration through a membrane. In the case of this egg cell, the solvent (small water molecules) moved from the highly concentrated area of molecules within the cell to the lower concentration of molecules outside of the egg cell. This balanced out the amount of molecules in and outside of the cell, essentially spreading them out equally. This type of diffusion is called passive diffusion because it required no energy for the molecules to move from an area of high concentration to low. This lab demonstrated the concept we learned in class that all membranes are semipermeable. Semipermeable membranes mean that they allow certain molecules through, and keep others out, as we observed from the egg immersed in a sugar solution. Typically, it is easier for smaller molecules to move across membranes, which makes sense because sugar molecules are large compared to water molecules. From the concepts I learned in this lab, I can now understand the reasoning behind everyday processes. When fresh vegetables are sprinkled with water at markets, it is to put more solvent outside the plant cells than there is inside. this would ensure the plants do not shrink and that they stay looking fresh and plump. When roads are salted to melt ice, plants alongside the road shrink and die. This is because there is more solute (salt) outside the plant cells, so when diffusion takes place, the plants shrink, just like the egg cell in this lab. Based off this experiment, I would like to learn more about to what extent the egg cell can and will shrink. I would like to test to see if more sugar molecules are added to the outside of the egg cell again, if the egg cell would shrink more or simply stay the same. the reason I would like to know this is because I understand the cell will diffuse so that the amount of molecules stabilizes in and outside the cell, but i wonder if there is a certain point at which the egg cell will have diffused too many times. I am curious to see if the cell can become "worn out" and simply not diffuse further.