The membrane contains polysaccharides. When we put the membrane in an iodine solution to test for polysaccharides, it turned black. The membrane contains this because it uses polysaccharides to communicate with other cells. The egg white had proteins floating around in it. We know this because when the separated egg white was dropped in copper sulfate, a chemical that tests for peptide bonds, the solution turned purplish. The egg white may contain proteins for helping the developing chicken embryo grow. The proteins would provide nourishment and vital ingredients for life.The egg yolk was composed of lipids. This was learned when the broken down yolk was put in a solution of Sudan IV. Soon, it turned a shade of orange. The yolk probably contains lipids because it is actually a cell. Cells have phospholipid membranes, so this is the most likely reason for a positive lipid test.
One possible error is that a sample was contaminated. If one sample was accidentally mixed with the one being tested, it may show positive results when in reality the macromolecule is only present in the contaminant. If this happened, then the macromolecules that the evidence proved may not normally be present. Another mistake that could have occurred is if an inadequate amount of testing substance was used. In the procedure, it only said how many drops should be added. This is not a very accurate measurement and people may have also miscounted the amount of drops of a chemical they added. This may cause no results to be displayed even when a part of the cell contains a certain macromolecule. These inaccuracies can be remedied in the future by assigning each table a certain part of the egg rather than having each group test every single part of the egg. This new procedure would reduce the chance of contamination. The amount of testing chemical should also be changed from "drops" to "milliliters". This is a more standard and widely accepted measurement unit and would help prevent not using enough testing solution.
The purpose of this lab was to learn about the function and location of macromolecules in the cell. This relates to an activity I did in seventh grade where we made a chart of the macromolecules and wrote facts about what they did and where in the cell they are found. What I learned in this lab can be applied to situations where I may need to retrieve a certain macromolecule from the cell. With this information, it will be easier to know where the molecule is and how to isolate it.
Monosaccharide Test tubes- From the left: water, membrane, white, yolk
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