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Clockwise starting from top left: Egg Membrane, Egg White, Egg Yolk, Pure WaterEgg Macromolecule Lab Analysis
In this lab we asked the question: Can macromolecules be identifies in an egg cell? And we found an overarching answer that macromolecules can be identified in all parts of the egg cell, whether it is the egg yolk, the egg membrane or the egg white.
Egg Membrane |
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| The color change for the egg membrane in Sudan III |
Evidence: When the Sudan III was mixed with the egg membrane, the sample did turn to a shade of dark orange. On a rating scale of 0 to 10, (0 = color of the negative control, 10 = very dark shade of orange), we ranked the color change to be 8.5 - The picture to the right shows the egg membrane mixed with Sudan III. This data clearly indicates that there is a strong presence of lipids in the egg membrane.
Reasoning: The bilayer of the cell membrane is made up of phospholipids - which are lipids what have a phosphate group in its molecule - nevertheless still lipids that are a major part of all membranes. Other types of lipids that are found in the egg membrane include cholesterol and glycolipids. Cholesterol maintains membrane structural integrity and fluidity, making it another essential part of the membrane. Glycolipids help maintain the stability of the membrane and act as a recognition site for certain chemicals to pass in and out of the cell membrane. All in all, lipids are a major and essential part to the function and structure of cell membrane, thus are present in the cell membrane.
Egg White
Claim: The Egg White tested positive for the macromolecule of protein. We tested the presence of proteins in the egg white by mixing the egg white solution (shown in the top right of the picture at the very top) with sodium hydroxide copper sulfate, a solution which would turn any sample from blue to purple if the sample had proteins present.
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| Proteins present in Egg White |
Evidence: When sodium hydroxide copper sulfate was mixed with the egg white (shown in image to the right), the sample turned to a shade of dark purple. On the aforementioned rating scale, we rated the color change as a 6. The color change rating, compounded with the image shown to the right, clearly shows that there is a presence of proteins in the egg white.
Reasoning: The primary function of the egg white is to protect the yolk, also known as the nucleus of the egg cell. Proteins are found anywhere there is a membrane, because they (1) transport molecules and ions across the membrane as transport proteins, and (2) are attached to the lipid bilayer to help protect the cell as "integral membrane proteins." Some of the types of proteins present in the egg white are albumins, mucoproteins and globulins. The presence of proteins in egg whites does not just include transport and integral proteins, but is compounded by the fact that egg whites have 50 percent of the total protein in the egg. Thus, because the egg white's purpose is to protect the yolk, and proteins are found anywhere in the cell that serves as protection, proteins are present in the egg white solution.
Egg Yolk
Claim: The egg yolk tested positive for the macromolecule of lipids. We tested the presence of lipids in the egg yolk by mixing the egg yolk solution (shown in the bottom right in the very top image), with Sudan III, a solution which would turn any sample from red to orange if the sample had lipids present.
Evidence: When Sudan III was mixed with the egg white, the sample did turn to a shade of dark orange. On a rating scale of 0 to 10, (0 = color of the negative control, 10 = very dark shade of orange), we ranked the color change to be 4 - The picture to the right shows the egg yolk mixed with Sudan III. This data indicates that there is a presence of lipids in the egg membrane.
Reasoning: The primary function of the egg white is to protect the yolk, also known as the nucleus of the egg cell. Proteins are found anywhere there is a membrane, because they (1) transport molecules and ions across the membrane as transport proteins, and (2) are attached to the lipid bilayer to help protect the cell as "integral membrane proteins." Some of the types of proteins present in the egg white are albumins, mucoproteins and globulins. The presence of proteins in egg whites does not just include transport and integral proteins, but is compounded by the fact that egg whites have 50 percent of the total protein in the egg. Thus, because the egg white's purpose is to protect the yolk, and proteins are found anywhere in the cell that serves as protection, proteins are present in the egg white solution.
Egg Yolk
Claim: The egg yolk tested positive for the macromolecule of lipids. We tested the presence of lipids in the egg yolk by mixing the egg yolk solution (shown in the bottom right in the very top image), with Sudan III, a solution which would turn any sample from red to orange if the sample had lipids present.
Reasoning: Egg yolk has both cholesterol and phospholipid contents. Cholesterol is a type of lipid that is present in the egg yolk, which helps protect the egg yolk, which is the nucleus of the egg cell. Phosvitins are also a type of protein present in the egg yolk, and they are important in getting calcium and iron to the nucleus. LIPIDS are found wherever there are membranes, as they are essential for any protection inside the cell. As the yolk is the nucleus, it contains a nuclear membrane, and thus lipids will be present in the nucleus.
Possible Errors
While our hypotheses were supported by our data, there may have been some possible errors during the steps of the experiment. One of the possible errors is the amount of solution placed into the egg yolk, egg membrane or egg white. If there was too much solution, whether it was Sudan III, sodium hydroxide copper sulfate, iodine, or benedicts, the effect of the solution may have been exaggerated. If there was too little solution, the true effect and potential of the solution may not have been shown. Although we tried to set a specific number of solution drops to limit the possible error percentage, no one can account for how much one drop is, how many drops may have accidentally be put in.
Another possible error could have been the mixing of the solution and the sample. One person may have mixed the solution and sample extremely well, clearly showing the color difference and properly telling us what macromolecules were present in each of the samples, however others may have recorded their data without properly mixing their solution and sample. If this did happen, the effect of the solutions on the samples would not have been shown, and would give us incorrect data to analyze. However the possibility of this is minimum. Although some people may have mixed the solution and sample more than others (ex. more time spinning the tubes), the procedure told us to mix it well, and the couple extra mixes would not provide too much of a data difference.
Two recommendations that I would give when doing this experiment in the future is to put the exact amount of solution (that should be poured) into a separate petri dish, that way groups can simply pix it up, and dump all the solution into the sample. This would prevent any errors of the quantity of drops from taking place. The second recommendation that I would give is to give the exact number of seconds a student should spend mixing, or the number of times a student should spend mixing, thus eliminating any possibility of excess or insufficient mixing.
Practical Applications
This lab was done to demonstrate the macromolecules that are present in all parts of the egg cell. From this lab I learned that every part of the egg cell, whether it is the egg yolk, egg membrane, or egg white, has at least one, if not multiple, macromolecules present. This helps the understand the concepts of macromolecules - especially the structure and function that each macromolecule serves in each part of the egg cell. This also helps me better understand the importance of macromolecules, as well as what each part of the cell does. With better knowledge of macromolecule function, I can quickly relate to and understand different functions of different cells. Based on my experience from this lab, I can eat much better. I understand that the egg yolk is mainly a source of cholesterol and saturated fats, both of which are not extremely good for your body, and that egg whites are the egg's main source of protein. This has allowed be to shift my morning meals from being full egg omelets, to solely egg white omelets, something that will hopefully help me put on more muscle, and still stay very healthy.
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