Saturday, October 17, 2015
Unit 3 Reflection
Unit 3 was about cells. We focused on how cell's function, what they look like, and how they get their energy. It was easy for me to remember the parts of a cell required in making a protein and where they are located because of the analogy of each organelle being a part of a factory. It was more difficult to fully grasp and understand the processes involved for a cell to obtain energy. Cellular respiration is a process present in both plants and animals used to take food and turn it into energy, while photosynthesis is a process only in plants during which food is made from energy. Cellular respiration and photosynthesis are inverted. In this unit one of the in class activities was to draw and label the process of photosynthesis. This exercise made me realize what a high level of detail biology contains and the level of depth you can go into when studying the material. This made me a better student today than I was yesterday because I have learned that details are a crucial part but looking at the big picture is most important in understanding biology concepts. I am still left to wonder, however, what the proteins that cells make do in the body or plant. What role do they play that is so big that all the cells in the whole body have to help make them?
Wednesday, October 7, 2015
Egg Diffusion Lab Analysis
In this lab we answered the question: How and why does a cell's internal environment change, as it's external environment changes? We did this by placing one egg in a cup of sugar water and one egg in a cup of deionized water to see how these conditions would affect the egg. We measured the before and after circumference and mass of the eggs to find that the egg in sugar water shrunk and the egg in water grew.
1) As the sugar concentration increased the mass of the egg decreased by an average of 47.25% and the circumference decreased by an average of 22.94%. This change occurred because the sugar water solution was hypertonic to the egg, causing the egg to loose water and therefore shrink. The solvent of water diffuses from a lower concentration to a higher concentration to try to balance the amount of solvent and solute. However, the solute of sugar water couldn't move across the membrane into the egg because it's too large, causing the egg to only loose water and not gain sugar water.
2) The cell's internal environment changes as the external environment changes because cells naturally diffuse molecules in and out of its membrane through passive diffusion. Therefore, whatever molecules are outside the cell, this will affect what the concentration inside of the cell. When we put the egg in vinegar, it grew because vinegar is a solvent that diffused into the membrane. The external environment of the cell was the vinegar which affected the internal environment when the vinegar entered the cell, causing it to expand. However, when the egg was placed in sugar water, which is a solute, the egg shrunk because the solvent diffused out of the membrane to the external high concentration of solute outside the cell.
3) This lab demonstrates the biological principle of passive diffusion. During passive diffusion, transport proteins act as pores that allow molecules to slide through like a straw. This diffusion also acts as a filter because molecules that are too large cannot diffuse through the transport proteins. The solute of sugar water cannot passively diffuse through the cell membrane because its molecules are too large.
4) Fresh vegetables are sprinkled with water at markets to maintain turgor pressure. The vegetables look more appealing to customers when they are not shriveled up and water diffuses into the vegetables, causing them to expand. As humans, we shouldn't drink too much salt water because it causes our cells to loose water. The water in our cells diffuses to the high concentration of salt outside the cell, causing our cells to shrink and eventually die. Similarly, the plants along the side of the road shrivel up when salted because the water inside the plant cells diffuses out.
5) I would create an experiment testing whether plant and animal cells react the same when placed in sugar water. Would they both loose the same amount of water? Would they loose water at the same rate? I would test for the difference of diffusion in plant and animal cells.
1) As the sugar concentration increased the mass of the egg decreased by an average of 47.25% and the circumference decreased by an average of 22.94%. This change occurred because the sugar water solution was hypertonic to the egg, causing the egg to loose water and therefore shrink. The solvent of water diffuses from a lower concentration to a higher concentration to try to balance the amount of solvent and solute. However, the solute of sugar water couldn't move across the membrane into the egg because it's too large, causing the egg to only loose water and not gain sugar water.
2) The cell's internal environment changes as the external environment changes because cells naturally diffuse molecules in and out of its membrane through passive diffusion. Therefore, whatever molecules are outside the cell, this will affect what the concentration inside of the cell. When we put the egg in vinegar, it grew because vinegar is a solvent that diffused into the membrane. The external environment of the cell was the vinegar which affected the internal environment when the vinegar entered the cell, causing it to expand. However, when the egg was placed in sugar water, which is a solute, the egg shrunk because the solvent diffused out of the membrane to the external high concentration of solute outside the cell.
3) This lab demonstrates the biological principle of passive diffusion. During passive diffusion, transport proteins act as pores that allow molecules to slide through like a straw. This diffusion also acts as a filter because molecules that are too large cannot diffuse through the transport proteins. The solute of sugar water cannot passively diffuse through the cell membrane because its molecules are too large.
4) Fresh vegetables are sprinkled with water at markets to maintain turgor pressure. The vegetables look more appealing to customers when they are not shriveled up and water diffuses into the vegetables, causing them to expand. As humans, we shouldn't drink too much salt water because it causes our cells to loose water. The water in our cells diffuses to the high concentration of salt outside the cell, causing our cells to shrink and eventually die. Similarly, the plants along the side of the road shrivel up when salted because the water inside the plant cells diffuses out.
5) I would create an experiment testing whether plant and animal cells react the same when placed in sugar water. Would they both loose the same amount of water? Would they loose water at the same rate? I would test for the difference of diffusion in plant and animal cells.
Tuesday, October 6, 2015
Egg Cell Macromolecules Lab Conclusion
In this lab we asked the question: Can macromolecules be identified in an egg cell? We found that there are proteins in the egg membrane, polysaccharides in the egg white, and lipids in the egg yolk. Proteins had a 4 out of 10 color change in the egg membrane. The membrane turned the color purple when sodium hydroxide and copper sulfate were added to it because of the presence of proteins. This is because of transport proteins are present in the membrane to that let things in and out of the cell. This data supports our claim that proteins are in the membrane because they serve as "gateways" to diffuse molecules into the cell. Polysaccharides had a 5 out of 10 color change in the egg white. The egg white turned black when iodine was added because of the polysaccharides. They tested positive in the egg white because polysaccharides store energy and serve as food that surrounds the chick in the egg yolk. The data supports our claim that polysaccharides are present in the egg white because polysaccharides have a useful function in the egg white as energy. Lipids had a 5 out of 10 color change in the egg yolk. The yolk turned orange when Sudan 3 and water were added because of the presence of lipids. Lipids were found in the yolk because the membrane surrounding the yolk is made up of phospholipids. This data supports our claim because lipids are essential in the yolk to keep it enclosed and separate from the egg white.
Our data was not as accurate as it could have been because of a few possible errors. One possible error is the amount of membrane each tester ripped off to test. The procedures of the experiment gave a milliliter amount of membrane to test which left students guessing how much membrane to use because the membrane is not liquid and can not be measured in milliliters. Most testers ended up guessing how much to use by ripping a small piece off. This affected our results because if the tester didn't use a large enough sample of the egg membrane, some of the macromolecules could have not tested positive because there were not enough of that molecule on the small sample used. In future experiments I would recommend editing the procedures to give a weight measurement for students to weigh the sample of membrane to make sure a large enough sample is used. Another possible error is that there was no timing instructed for how long to wait for each part of the egg to change color. Some tester may have been in more of a rush and didn't give their samples a long enough time to test color. This affected the experiment because some of the macromolecules that were present didn't test positive because not enough time was given for them to change color. For future experiments I would recommend adding a time in the procedures to clarify how long to wait for color change.
The purpose of this lab was to demonstrate the presence of macromolecules in different parts of the cell by testing an egg. From this lab I learned about the connection between the function and location of the four macromolecules which helps me understand how the macromolecules help cells function. Based on my experience with this lab I now am aware that eggs are incredible healthy because they contain all four macromolecules that are all crucial to the nutrition of our bodies.
Our data was not as accurate as it could have been because of a few possible errors. One possible error is the amount of membrane each tester ripped off to test. The procedures of the experiment gave a milliliter amount of membrane to test which left students guessing how much membrane to use because the membrane is not liquid and can not be measured in milliliters. Most testers ended up guessing how much to use by ripping a small piece off. This affected our results because if the tester didn't use a large enough sample of the egg membrane, some of the macromolecules could have not tested positive because there were not enough of that molecule on the small sample used. In future experiments I would recommend editing the procedures to give a weight measurement for students to weigh the sample of membrane to make sure a large enough sample is used. Another possible error is that there was no timing instructed for how long to wait for each part of the egg to change color. Some tester may have been in more of a rush and didn't give their samples a long enough time to test color. This affected the experiment because some of the macromolecules that were present didn't test positive because not enough time was given for them to change color. For future experiments I would recommend adding a time in the procedures to clarify how long to wait for color change.
The purpose of this lab was to demonstrate the presence of macromolecules in different parts of the cell by testing an egg. From this lab I learned about the connection between the function and location of the four macromolecules which helps me understand how the macromolecules help cells function. Based on my experience with this lab I now am aware that eggs are incredible healthy because they contain all four macromolecules that are all crucial to the nutrition of our bodies.
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