Lab RECAP: Plasmolysis In this lab we learned about plasmolysis. We completed this lab to study the effects of salt and distilled water on elodea cells. We first took a leaf of an elodea plant and placed it on a slide with a drop of distilled water. We then placed a cover slip over the leaf and observed the leaf under a compound microscope with lenses that magnified the cells 100 times and then under a lense that magnified the cells 400 times. We then recorded what we saw by drawing a couple cells in each power. Next, we placed a drop of saltwater on the same leaf and observed it again under the same two magnifications. We recorded what we saw by drawing a the group of cells that we saw. Finally, we added a drop of distilled water to wash out the salt water and repeated the procedure of observing and recording at the two different powers. I knew that salt dissolves in water and that the salt may affect the water levels within the cell. I also knew that when salt was exposed to a plant, the plant wilted. However, I did not have a good understanding of plasmolysis, so I did not have an idea on what was going to happen to the cells during the lab.
When I looked at the cells with a drop of distilled water, I saw a rigid cell wall that surrounded each cell. I also saw a cell membrane that lined the cell and green chloroplasts that lined each membrane. The whole cell had a green hue and the chloroplasts were a brilliant green. I saw tiny cells with green circles moving inside of them under the 100 times magnification. However, in the 400 times power, I could see the separation between the cell wall and the cell membrane more than in the 100 times magnification. The cell’s volume did not surpass the cell wall. When I added a drop of salt water to the leaf, the cell wall remained in place, whereas the cell membrane shrunk and did not line the cell wall as it was with the distilled water. The chloroplasts moved with the cell membrane and were closer to the each other. The chloroplasts were compressed together when the cell was exposed to salt, whereas in the distilled solution, the chloroplasts were able to move freely. When the plasmolyzed cells were under the 100 times magnification, I could see the shrinkage of
If feeding efficiency and reproduction have a direct correlation, and a population started with equal proportions of individuals with each of three feeding types, metal spoon, metal knife, and plastic fork, the frequency of the population with metal spoons as their feeding structure will increase in the next generation. While the frequency of metal knifes and plastic forks will decrease. Furthermore, since the organisms with the metal spoon feeding structure have a higher fitness level, this population will evolve by natural selection to a point where the metal spoon phenotype will be in abundant. While the organisms with metal knifes and plastic forks phenotypes will decrease in frequency due to the lack of reproduction. Eventually, if this population persist overtime, most of the organisms, if not all, will have the metal spoon phenotype, while very few, if not any, will have the metal knife or the plastic fork phenotype.
The Osmosis and Diffusion lab was conducted to provide us with information on how built up mucus affects those conflicted by the recessive genetic disease, Cystic Fibrosis., due to a mutation to the membrane regulating chloride (Cl-). This mutation prevents the Cl- from leaving the cell causing the amount of sodium (Na+) in epithelial cells, which results in extreme mucus on the lungs and airways causing this disease to be fatal if not treated but treatment does not equate to a long lifetime. During the lab we took the data from three parts: Diffusion, Osmosis in an Elodea Cell, and finally the Role of Osmosis in Cystic Fibrosis. During Part 1 we looked at diffusion across a semipermeable membrane for starch and glucose, which resulted in both having a negative solution when placed in a semipermeable membrane. Then we looked at osmosis in the Elodea Cell to watch for the occurrence of Plasmolysis, when a cell’s plasma membrane pulls away from the cell, and how a plant cell is affected by both hypertonic and hypotonic solutions. Finally, we observed the role of Osmosis in Cystic Fibrosis using dialysis bags to represent a normal cell and a Cystic Fibrosis cell with the normal containing 1% NaCl while the Cystic Fibrosis bag contained 10% NaCl. After we ran the experiment, we looked at the Percent Change in Mass and compared them after 30 minutes. We found that Cystic Fibrosis cells didn’t change mass as much as the normal cell ending with a change in mass over -1%. The
The main purpose of the experiment was to test the idea that water would move from the higher concentration to the lower concentration. In order to test this theory, we placed potato slices in 7 different containers, each containing different concentrations of NaCl, to measure the weight change from osmosis. The containers ranged from 0M NaCl all the way to .6M NaCl. We measured the potato slices before and after placing the slices in the solutions and recorded the net change in weight to determine the tonicity of the potato cells. Our results showed that the potato slices put in a NaCl solution of .2M or higher lost weight and the potato slices put in a NaCl solution of .1M or lower gained weight. This shows that the osmolarity of the potato falls within the range of .1M to .2M, and it also proves the process of Osmosis by having the higher concentration move to the lower concentration. In addition to this, it can be concluded that the osmolarity of cells can be determined by observing the affects of osmosis.
Finally, it could also be a hypertonic solution which is when there is a higher concentration of solute in the solution than in the cell and therefore the water leaves the cell. This make the cell plasmolyzed or “shrunken”. In our experiment this means that the potato cell would
Water diffuses across the membrane from the region of lower solute concentration (higher free water concentration) to that of higher solute concentration (lower free water concentration) until the solute concentrations on both sides of the membrane are equal. The diffusion of free water across a selectively permeable membrane, whether artificial or cellular, is called osmosis. The movement of water across cell membranes and the balance of water between the cell and its environment are crucial to organisms. ("Diffusion And Osmosis - Difference And Comparison | Diffen"). A semi-permeable membrane known as the cell membrane surrounds the living cells of both plants and animals. Both solute concentration and membrane permeability are
Observation: no bugs were found except small, black, gnats were all close to the ground.
This lab is about moving genes from one thing to another using plasmids. Plasmid has the ability to replicate, so it replicates independently, and separately from the chromosomal DNA. Plasmid are one or more small piece of DNA and they enter cells as a double strand DNA. When they enter the cell as a doubke strand they do not invade he chromosomal DNA. We will also transform bacteria into GFP which is mainly from the jelly fish Aequorea Victoria. The GFP causes the the jelly fish to fluorescent and glow in the dark. After the transformation, bacteria starts to make the GFP which causes them to glow a green color under a ultraviolet light.
The objective of this experiment is to develop an understanding of the molecular basis of diffusion and osmosis and its physiological importance. Students will analyze how solute size and concentration affect diffusion across semi-permeable membranes and how these processes affect water potential. Students will also calculate water potential of plant cells.
Ps: the iodine was already really dark so it was very hard to see much difference between the control and the others.
The major storage polysaccharide in plants is starch. These molecules would be found in abundance in the stroma in the plant tubers where it is found as granules. Glucose is stored mainly in the form of starch granules, in plastids like chloroplasts and amyloplasts. Plant starch starts out as glucose, but glucose is very hard for plants to store, so it is converted to starch through polymerization. Amyoplasts turn the glucose into starch and move it to the stroma, and in tubers the stroma is a place to store the food (starch), and when plants need the energy in the starch, it converts the starch back into glucose.
The lost of water from the vacuoles and cytoplasm pulled the cell membrane away from the cell wall. The water was diffused from a hypotonic solution to a hypertonic solution. Because the water flowed out of the cell by osmosis, the cell became more flaccid and then plasmolysed.
Plant cells react differently to osmosis than animal cells. When an animal cell is placed in a hypertonic solution, water will leave the cell causing it to shrink, this is known as crenation. When a plant cell is placed in a hypertonic solution the cell membrane will pull away from the cell wall, making the plant flaccid, this is known as plasmolysis. When an animal cell is placed in a hypotonic solution, water will rush in to the cell, causing it to swell and sometimes burst. A plant cell placed in a hypotonic solution will also swell due to water rushing in, but will resist rupturing due to the rigid cell wall. Plant cells become more rigid in a hypotonic solution.
The way to get the full results of this lab was through the process of osmosis. Osmosis is the movement of water across a membrane into a more concentrated solution to reach an equilibrium. When regarding cells osmosis has three different terms that are used to describe their concentration. The first of these words is isotonic. Cells in an isotonic solution show that the water has no net movement and the amount of water that goes in is the same that goes out. Isotonic comes from the root iso, which means equal. This makes sense because the definition of isotonic is: same concentration. The second out of three words is hypotonic. Cells in a hypotonic
In animal cells, the movement of water into and out of the cell is influenced by the relative concentration of solute
To study the effects of hypotonic, hypertonic and isotonic solutions on plant and animal cells.