Unit 3 Reflection

After studying about Unit 3, I have learned quite a lot about cells. From exploring the inside of the cells, to their history and evolution, Cells have gone a long way from the beginnings of Earth. I understand most of the history and reactions that occur within the cell, but struggle a little when trying to remember the many parts of a Eukaryotic Cell. Otherwise, I understand how prokaryotic cells evolved to become the very cells in our body, or photosynthesis, osmosis, diffusion and cellular respiration.

A quick summary of Unit 3 would be that it is about cells. Cells are either prokaryotic / singular or eukaryotic / multicellular. They evolved from the single celled organisms that swarmed the lifeless earth, to autotroph cells that produce oxygen and food for the cell, giving life to Earth. Later on, Heterotroph cells became more popular as it ate the autotroph cells. By accident, the autotroph cell sometimes would survive getting eaten and merge with the cell. This made the first eukaryotic cells, with an inside that produces energy and an outside that protects the inside. This type of cell became more and more popular till it had also evolved to different cells still related to the original. Photosynthesis was one way cells produced energy and food for themselves, and cellular respiration was the other part of the cycle, that used the products of photosynthesis to make its reactants. Osmosis and diffusion were ways that the cell adapted to changing environments and the transfer of materials.

From learning this unit, I have learned my many flaws, but also learned more about the subject and ways to improve myself. I hope this summary and overview about this unit was helpful, and can be used in studies.

Egg Macromolecule Conclusion

Derek Fung P5

Aug. 28, 2015

Egg Macromolecule Conclusion

In the lab we had finished, we were trying to test if macromolecule can be identified in an egg cell. For each part of the egg we had tested, we had found that there were some macromolecules in each parts, and little or none in other parts. In the egg membrane, we found lipids and polysaccharides; in the egg white, polysaccharides and in the egg yolk: lipids, polysaccharides, and monosaccharides. When we used special liquids on each of the egg parts, the part changes color, depending on the part or the substance used. For example, some parts turn green if the substance used identifies that there are monosaccharides in the part. This evidence proves that there are carbohydrates in the egg, because of the color changes when you use.

Even with this evidence here, we have made some mistake here and there in the experiment. One such example is during the test where we were looking for proteins in the parts. While we were doing so, we found that the substance turned all but one part mostly blue, except the egg yolk, which was a mixture of yellow and blue. To think that the egg had no proteins make me think that there was an error in the procedure, but several others had this problem also, which made it hard to know if I did it right or wrong. This error could take away an important part of the results that we could have lost if the procedure was done wrong. Another error that could have changed the results would be when we were using the pipette. While we were adding each of the egg parts to the containers, we used the same pipette for each of the parts, thus mixing a small part of each of the egg into the other. This error could have changed the effects of the substance we used on each part, making it produce a different color than what we had expected. A few ways to ensure that these errors could be avoided are by having a separate pipette for each of the containers when transferring a sample of each of the egg parts, and by spending a lot more time on the protein test to see if there is progress going on.

The purpose of this lab was to find the macromolecules and know its uses in each of the egg parts. This is a review of what we had learned in class about macromolecules and an in-depth review of how the macromolecules were used in each parts. This lab can be applied to parts other than the egg, such as the human body or animals, since egg cells are nearly the same as the humans or animals.

Egg Diffusion Lab Analysis

In the Egg Diffusion Lab, we had found that the eggs in the sugar water had shrunk, while there was no change in the egg within the pure water. When we put the egg in the sugar water, there would be more solute than solvent outside the cell. Because of this difference, the water / solvent inside the cell would come out, shrinking the cell. This, with the large amount of solute in the water, caused the mass and the circumference of the egg in the sugar water to shrink considerably. As the external environment changes, the internal environment of the cell adapts according to the differences between the outside and the inside of the cell. When we put the egg in vinegar, we dissolved the membrane that prevents materials from entering the egg. After we had done that, we were able to add the eggs without the membrane into either the pure or sugar water. Due to passive diffusion, the materials inside the water diffused into the egg and changed the amount of solvent or solute inside, causing changes in the egg. The high concentration of either solvent or solute goes into an area of low concentration in the egg.

This lab had demonstrated examples of diffusion and its effects, which we had learned in class, that we could apply to other situations. Vegetables are given water to add more solvent inside, making the cells inside the plant grow, and the plant itself will grow with it. People add salt to ice in order to add solute inside the ice, making the hypertonic ice shrink and disappear into water. The salt / solute makes the high concentration of frozen water inside the ice go towards the low concentration of salt, making the cells shrink and turning the ice into water. This experiment would lead others to try other experiments. One such experiment that I think might be tested would be putting salt onto ice and see what could make the ice melt faster. This experiment uses diffusion and also is a great example of other things.