Unit 3 Reflection

This unit was all about the cell. We learned about the different organelles in the cell and their functions, along with a few very important processes like photosynthesis and cellular respiration. Some themes for this unit were how the cells function inside an organism and how their are different processes that keep us and other organisms alive. Some strengths that I have on this unit was the process of diffusion and osmosis because I learned about them last year. Some weaknesses that I have are the different steps in both cellular respiration and photosynthesis. After the vodcasts and the labs that we did in class, I feel like I am a better student than before this unit because before I had no idea that a cell was so detailed and had so many different parts. Also I had no idea that photosynthesis and cellular respiration were so complex. Now, I have a better understanding of what really goes on inside a cell. I want to learn more about how what we have learned applies in modern applications. For the test, I am planning on reading through the vodcast notes and also to try and create a chart of the different organelles and their functions just by memory. Also I will draw a plant cell and name the parts of the plant, along with naming the different parts that incorporate the process of photosynthesis and cellular respiration.

Diffusion

Photosynthesis and Cellular Respiration

Egg Diffusion Lab Conclusion

In this lab we asked the question, "How and why does a cell's internal environment change as it's external environment changes?" To test this, we put two eggs in vinegar for 48 hours. That made the cell membrane degrade. After that we took the two eggs and put one in demonized water and the other in corn syrup. Before we put them in the water and the corn syrup we measured the mass and circumference. After two days, we measured the circumference and the mass again. As the sugar concentration increased, the mass and circumference of the egg decreased. The circumference decreased by an average of 22.94% and the mass decreased by an average of 47.25%. The reason that the egg shrunk is because the corn syrup is hypertonic. This means that there is less solute, or sugar, outside than inside the cell, so the solutes inside want to go from a high concentration to low concentration, but they cannot because of the membrane. Thus, the solvent goes outside, making the cell smaller. A cell's internal environment changes when its external environment changes because the external environment either had more or less solutes than inside the cell. This would make the internal environment to change because of diffusion and how the solutes and solvents always want to be balanced. This would occur because the solutes would not be able to enter or exit the cell, so the solvents need to go from the high concentration to low concentration. This lab demonstrates the principle that states diffusion, which goes from high to low concentrations, and also about hypertonic solutions which shrivel up the cell. Fresh vegetables are sprinkled with water because otherwise, the cells will shrivel up making the fresh vegetables not so fresh and good looking anymore. Salting the roads will make the plants on the sides of the roads shrink because there will be more solutes outside, the salt, which will make the solute inside the plants try and move to the lower concentration, but they will not be able to. During this process, the solvent will passively diffuse to the outside, shrinking the cell. One experiment I would like to test is doing testing a different fruit or vegetable. The reason that I would do this is because I would like to find out if all fruits and vegetables respond like the egg did.

Egg Macromolecules Lab Conclusion

In this lab, we asked the question, "Can macromolecules be identified in an egg cell?". We found that in the egg memebrane, one of the macromolcules present was lipids. The reason we found that lipids are inside the membrane was because of the indicators that we put in. For the lipids, we used Sudane 3, which changed the color from red to orange. This proves that lipids are infact present in the membrane of the egg. Also, we know that lipids should be inside the membrane because a membrane is made of phospholipids. Moving onto the egg white, one of the macromolecules present was proteins. The color changed from clear to white, when using copper sulfate. Since there is a color change, we know that proteins are present. Also, we know that proteins are supposed to be in the egg white because the enzymes help with the process of growth and development. Finally, when we tested for macromolecules inside the yolk, we found that monosaccharides were present. When I added the Benedict solution to the egg yolk, the color changed from turquoise blue to green blue. This shows that monosaccharides are present. The reason that macromolecules are inside the egg yolk is for energy. The yolk needs the energy to carry out the functions of the cell.

One possible error that could have occurred in the experiment is the amount of drops of each solution that is put in. For example, if someone puts more of the Benedict solution inside one of the test tubes. This could have affected the experiment because then there would be more pigment change in one of the test tubes, making the observations and ratings different. This would throw of the data. Another error that could have occurred is the egg was not separated properly into the three test tubes. For example, the egg membrane could have mixed with the yolk and when the solution was added there could have been an extra color change. This would tell the analyzer that there is that macromolecule in the yolk, when the macromolecule was not supposed to be found there. One recommendation that could improve the experimental procedure is being more careful with the droppers and the amount that is supposed to be put in the test tubes. Another recommendation could be when you are separating the egg yolk, you can use a strainer to get only the yolk.

The purpose of this lab is to show what macromolecules are used in different parts of the cell. This lab relates to what we have done in class because we have learned about the macromolecules and where they are used inside a regular cell and the lab was done to show where the macromolecules in a egg are located. The outcome from this lab could be applied to other things like understanding the reason of why macromolecules are found where they are in a cell.