Egg Macromolecules Lab

Egg Macromolecules Lab

             In this lab, we asked the question, can macromolecules be identified in an egg cell? We tested for proteins, lipids, monosaccharides, and polysaccharides. If a protein was present, then the sample would turn from blue to purple when adding sodium hydroxide and copper sulfate. For lipids, we added a chemical called Sudan III and if lipids were present, the sample would turn from red to orange. With monosaccharides, we added benedicts solution and put the test tube in boiling water, and if they were present, the sample would turn from blue to green or orange. Polysaccharides would turn from brown to black when adding iodine if the macromolecule was there. 

             We found that some macromolecules can be found in the egg membrane. The two macromolecules found in the egg membrane are lipids and proteins. For proteins, the test tube turned purple and was relatively dark, ranking 9 in a scale from 0-10. The proteins must have shown up in the membrane because there are transport proteins that are in the membrane. For lipids, the test tube was an orangery pink, ranking a 7 out of 10. Based in our vodcast, we leaned that lipids make up membranes therefore, this data supports our claim because an egg membrane is no different than a cell membrane. 

             We also found that macromolecules can be found in the egg white as well. The only macromolecule identified was proteins. The tube turned purple with a 7 out of 10 and was a lighter shade of purple that the egg membrane. This data supports our claim because enzymes, which is a type of protein, is located in the cytoplasm which would be the egg white. We learned about this in a previous vodcast. 

             In the egg yolk, we found a good amount of proteins. In the test tube for proteins, the top layer of yolk was a purple where the sodium hydroxide and copper sulfate actually made contact with the yolk. I think that the yolk was too thick for the solutions the go completely through, therefore only the top layer of the yolk turned purple. The color was a 6 out of 10 and a bit muddled. This supports our reasoning because the chick inside the yolk is going to require protein to grow. According to the North Carolina Egg Association, the yolk contains a little less than half of the protein. 

             While our hypothesis was supported by our data, there could have been error due to the inconsistent drop size when putting the chemical solutions into the three different parts of the egg. This was the case for the polysaccharide test, the protein test, and the lipid test. For the monosaccharide test, the test tubes may have been taken out too early and for the proteins test, there wasn't consistent timing. The inconsistent drop size may be fixed by pouring the needed amount of the solution into a beaker and pouring it all at once into the test tube. As for taking out the test tubes too early from the boiling water, we should just be more careful in watching the time. But for the protein test and inconsistent timing, we could have someone do it one at a time and watch the clock for 30 seconds before recording the results and going to the next test tube, or when short on time, have four people doing it at once.

             This lab was done to demonstrate how macromolecules are distributed within a cell. From this lab I learned that proteins are a major part of the cell and polysaccharides and monosaccharides aren't usually found in a cell. It helped me understand the concept of macromolecules and how they are used in a cell. Based on my experience from this lab, I can apply my knowledge when dealing with cells and macromolecules again.