Egg Cell Macromolecules Lab Conclusion

In this lab we asked the question: Can macromolecules be identified in an egg cell? We found that there are proteins in the egg membrane, polysaccharides in the egg white, and lipids in the egg yolk. Proteins had a 4 out of 10 color change in the egg membrane. The membrane turned the color purple when sodium hydroxide and copper sulfate were added to it because of the presence of proteins. This is because of transport proteins are present in the membrane to that let things in and out of the cell. This data supports our claim that proteins are in the membrane because they serve as "gateways" to diffuse molecules into the cell. Polysaccharides had a 5 out of 10 color change in the egg white. The egg white turned black when iodine was added because of the polysaccharides. They tested positive in the egg white because polysaccharides store energy and serve as food that surrounds the chick in the egg yolk. The data supports our claim that polysaccharides are present in the egg white because polysaccharides have a useful function in the egg white as energy. Lipids had a 5 out of 10 color change in the egg yolk. The yolk turned orange when Sudan 3 and water were added because of the presence of lipids. Lipids were found in the yolk because the membrane surrounding the yolk is made up of phospholipids. This data supports our claim because lipids are essential in the yolk to keep it enclosed and separate from the egg white.

Our data was not as accurate as it could have been because of a few possible errors. One possible error is the amount of membrane each tester ripped off to test. The procedures of the experiment gave a milliliter amount of membrane to test which left students guessing how much membrane to use because the membrane is not liquid and can not be measured in milliliters. Most testers ended up guessing how much to use by ripping a small piece off. This affected our results because if the tester didn't use a large enough sample of the egg membrane, some of the macromolecules could have not tested positive because there were not enough of that molecule on the small sample used. In future experiments I would recommend editing the procedures to give a weight measurement for students to weigh the sample of membrane to make sure a large enough sample is used. Another possible error is that there was no timing instructed for how long to wait for each part of the egg to change color. Some tester may have been in more of a rush and didn't give their samples a long enough time to test color. This affected the experiment because some of the macromolecules that were present didn't test positive because not enough time was given for them to change color. For future experiments I would recommend adding a time in the procedures to clarify how long to wait for color change.

The purpose of this lab was to demonstrate the presence of macromolecules in different parts of the cell by testing an egg. From this lab I learned about the connection between the function and location of the four macromolecules which helps me understand how the macromolecules help cells function. Based on my experience with this lab I now am aware that eggs are incredible healthy because they contain all four macromolecules that are all crucial to the nutrition of our bodies.