Egg Diffusion Lab Analysis

When the sugar concentration of the solution the egg was placed in increased, the mass and circumference of the egg both became smaller. This change was caused by the passive diffusion of water. In the solution of sugar water, sugar is the solute, and water is the solvent. The sugar water had a higher concentration of solute to solvent than the egg. Solutes like sugar are too big to diffuse across the egg's membrane, but solvents can passively diffuse across the egg membrane. Since diffusion's goal is to reach equilibrium, or the point when the concentrations of solute to solvent are equal, solvent molecules moved out of the egg's membrane in order to dilute the sugar water outside of the egg. Because water left the egg in sugar water, the egg shrank.

24 hour time lapse of our Egg Diffusion Lab. Egg on left in corn syrup, egg on right in DH2O pic.twitter.com/wdfujQyBXM

— Mr. Orre's Class (@OrreBiology) October 5, 2016

A cell's internal environment changes as it's external environment changes because of diffusion. Because cells want to reach equilibrium with their surrounding solutions, they either shrink or grow, depending on their environment. When the egg was placed in vinegar, it lost its shell because vinegar is acidic. When the egg was placed in water, it grew, because the egg has more solutes than water, since pure water has no solutes. And when the egg was placed in sugar water, it shrank because the sugar water had more solutes than the egg.

This lab demonstrates the biological principal of osmosis. Osmosis is the diffusion of water across a selectively permeable membrane. This membrane refers to the egg's membrane. Because osmosis is a type of diffusion, the water will attempt to go from a low concentration of solute to a high concentration of solute in order to reach equilibrium. This is the process that happens when the egg is placed in sugar water. This lab also demonstrates the biological principal of tonicity, which is the ability of a surrounding solution to cause a cell to gain or lose water. The sugar water was a hypertonic solution, meaning the solute concentration in the sugar water was more than that inside of the egg. The deionized water was a hypotonic solution, meaning the solute concentration in the egg was more than that in the surrounding solution.

Fresh vegetables are sprinkled with water at markets because the vegetables have less water, or solvent, and more solute. Because the cells of the vegetables have more solute than their surrounding, hypotonic solution of water, the vegetables will gain water, keeping them fresh for longer. When roads are salted to melt ice, plants along the roadside may wilt. When the ice melts, the resulting water combines with the salt to form a salt water solution. Since the cells of plants have less salt than the salt water, which is hypertonic compared to the plant cells, the plants lose water, causing them to wilt.

Based on this experiment, I would like to test the tonicity of other solutions. I would like to do this so I can find solutions that are isotonic to an egg cell. I would also like to test this with different cells, but since the changes in mass and circumference would be much harder to measure, I would probably test this with different types of eggs.

Egg Macromolecule Lab Conclusion

In this lab, we asked the question, "can macromolecules be identified in an egg cell?" We found that lipids are found in the egg membrane. We know that lipids are found in the egg membrane because when Sudan III was added to the egg membrane, the egg membrane turned light orange, which is a sign that lipids are present in the egg membrane. It is reasonable that lipids would be found in the egg membrane, since membranes are made of lipids. This data supports our claim because lipids were detected in the egg membrane and the egg membrane is made of lipids. We also found that monosaccharides are found in the egg white. We know this because after benedicts solution was mixed with the egg white and heated in boiling water, the egg white turned forest green, which means monosaccharides were found in the egg white. Because the egg white is food for the baby chick, it makes sense that egg whites are made of monosaccharides, the primary energy source. This data supports our claim because monosaccharides were detected in the egg white and the egg white is an energy source. Finally, we found that proteins were found in the egg yolk. We know this because when sodium hydroxide and copper sulfate were mixed with egg yolk, it turned dark purple, which is a sign that proteins were present. Since the egg yolk is the baby chick, the proteins were probably the chick's structural proteins. This data supports our claim because proteins were detected in the egg yolk and structural proteins are needed for something to live.









While our hypothesis was mostly supported by our data, there could have been errors due to an accident that happened during the beginning of the lab. During this accident, the egg white and egg yolk became mixed. This may have affected our results because both the egg white and the egg yolk were contaminated and couldn't really be accurately tested. There could also have been errors because not all of the test tubes had exactly 2 milliliters, since the pipettes were hard to use, and also because there were bubbles of air in the pipettes. Due to these errors, in future experiments I would recommend using spoons with circular holes in them, which would make it harder for the egg white and egg yolk to mix. I would also recommend having the students temporarily mark the test tubes for 2 milliliters so they wouldn't have to worry about inaccuracies with the pipettes.

This lab was done to demonstrate where macromolecules are found in the cell. Since an egg is a single cell, we now know where monosaccharides, polysaccharides, proteins, and lipids are found in a cell. From this lab, I learned that lipids are found in the membrane of an egg cell, which helps me understand that lipids make up membranes. I also learned that proteins are found in the egg yolk, which was going to become a baby chick, which helps me understand the concept of structural proteins. Based on my experience from this lab, I know now how to test for the presence of a macromolecule, which would be helpful if I needed to test an unknown solution for macromolecules in the future.