The Effects Of Environmental Stress On Cell Membranes

Certain substances are able to diffuse across plasma membranes under the right conditions through selective permeability. The selection of these certain substances allows for cells to maintain homeostasis, as these substances move from higher concentration to lower concentration. The purpose of this experiment is to see whether or not Lugol’s will be able to diffuse across dialysis tubing, which acts as a membrane. Lugol’s turns black when it interacts with starch, which will make the diffusion easy to see. This is all based off of a caterpillar eating a plant. The starch present in the leaves causes the caterpillar to produce amylase, which breaks down starch. In one experiment, the tubing will contain starch and amylase, while the other tubing

From the Elodea cells, we see the membrane pulling away from the cell wall in hypotonic solutions, flaccid in isotonic solutions, and firm in hypertonic solutions. We can apply these findings to the potato cells. The very soft potatoes are plasmolyzed (in hypertonic solution) , the less firm potatoes are flaccid (in isotonic solution), and the firm potatoes are turgid (in hypotonic solution). Using this we can correlate each response to the solution they were in. 6)

Purpose: To determine the concentration of solute in the potato’s cytoplasm by measuring the change

Aim: To investigate how effect of Detergent Concentration (cont.) has on Membrane permeability of Beetroot cells. Hypothesis: I predict that as detergent concentration increases, the solution will become less clear, plus mass increases. The increases in mass will indicate that the water potential of the Beetroot cell is lower than that of the surrounding sucrose solution. The Beetroot discs will become flaccid and decrease in mass if the water potential of the surrounding solution is lower than the water potential inside the beetroot cell.

The procedure of this lab is to determine if liver and potato cells contain natural buffers that resist large change in pH as 1. NaCl or 1. NaOH are added to the solution.

Hypothesis: To investigate the effect of different concentrations of ethanol on the permeability of beetroot cell membranes.

The cell membrane (Plasma membrane) functions to provide cell support, cell stability and control entry and exit of materials from the cell. This study was conducted to test the effects of environmental conditions such as the on beet root cell membrane (Beta vulgaris). Five trials using varied pH concentrations were tested and absorbance rates were monitored. The experimental results showed that the protein function decreased sequentially when the pH decreased. This allowed the betacyanin dye to leak out which created the color that was needed to determine the intensity and therefore the effect of the circumstances. This supported the hypothesis that the more acidic or basic the environmental condition around the beet cell, the more permeable the, membrane indicated by color intensity. Pigment leakage in the solution was analyzed by using a spectrophotometer.

The purpose of this experiment was to alter the cell membrane of the beets, in a given fashion, so that we can test how much betacyanin was able to cross the cell membrane of the beet through various treatment. In which after we would test the absorbance level of each treatment, run it through excel and observe which treatment was most effective at getting betacyanin through the cell membrane more.

In the beginning of this experiment, our TA added water, salt, and 75/25 hexane/acetone to spinach leaves to a blender and blended the mixture to assume equal amounts for each group and to avoid erros if each student had to do the blending. The addition of the water to the mixture allowed the it to separate into a distinct organic layer after being run in a centrifuge, which was available to be collected at the top of the centrifuge. Salt reduces solubility, which will force the organic parts of the mixture (the desired pigments for example) to separate into the organic layer at the top. Lastly, 75/25 hexane/acetone is added because this is a moderately polar solvent and will useful for both the non-polar and polar pigments present within the spinach leaves. A mixed solution of hexanes and acetone must be used because acetone is very polar, while hexane in very non-polar, and the spinach leaves contain both non-polar and polar pigments in them that are important in the extraction and for further analysis. The mixture was placed in the centrifuge so the solids in the mixture (mostly cellulose) could be separated from the liquids into separate distinct layers for further extraction and testing. In the tube, the organic substances separated into the top layer, whereas the water layer remains at the bottom of the tube below the solid layer made up of mainly cellulose.

Thus it forms holes, disrupting the membrane of the beetroot core which essentially prevents the betacyanin pigment from leaving the cell. Also, when exposed under heat, the cholesterol, glycolipids and phospholipids expand, putting pressure on the membrane from inside. The lipid part of the membrane will become liquid, making it open to leakage. The proteins in the membrane will denature, increasing the permeability in the surface. The combination of vibrating molecules and a denaturing membrane would disrupt the organized structure of the membrane. And eventually with a disrupted membrane, betacyanin pigment in the innermost compartment will leak out.

In this lab, neutral red was used as a pH indicator. The color changes from yellow to red in a basic solution to an acidic solution. The neutral red dye was applied to Saccharomyces Cerevisiae. When the S. Cerevisiae cells come in contact with the neutral red dye, the dye gets to the cell by crossing the cell membrane. The cell membrane is the outer surface of the cell that functions as a barrier. The outside of the cell membrane is made of lipid and membrane proteins (Hardin, 2012). It is selectively permeable, which means only select ions and molecules can pass through it by transport. Membrane transport can be actively or passively moving a substance from side of the membrane to another (Hardin, 2012). Passive transport does not require energy to move molecules across the cell membrane. Diffusion is a form of passive transport that moves molecules across the membrane from an area of higher concentration to an area of lower concentration. Osmosis, diffusion, and facilitated diffusion are all examples of passive transport. Active transport requires energy to move molecules across the membrane from areas of lower concentration to higher concentration. It requires energy because it pushes sodium ions (Na+) and potassium ions (K+) (Hardin, 2012). When the dye entered the cell, it also showed its location. Sodium azide (Na+N3-) is a metabolic inhibitor that blocks the flow of electrons along

As a result, if an animal cell were placed in pure water, it would eventually burst. This is because the membrane alone is not enough to support a turgid cell. For this reason I will use plant cells in my experiment. Method The aim of this experiment is to work out the water concentration of cell sap in potato cells.

Mr. A is exhibiting signs and symptoms of atrophy which is a decrease in cell workload. Mr. A muscle cell workload will decline as well as o2 and protein synthesis. Mr. A is experiencing several different forms of atrophy, with the first being disuse, which is a reduction in skeletal use. Secondly Mr. A is also exhibiting inadequate nutrition due to his diet of only biscuit and grits. Lastly, due to the compound fraction which means there is a break in the skin, there would be poor circulation. Mr. A is experiencing gas gangrene due to the compound fracture, and exposure to outside elements for the past few weeks he has been in the bed. There are 3 different types of gangrene.

Van’t Hoff’s Law suggests that the osmotic potential of a cell is proportional to the concentration of solute particles in a solution. The purpose of this experiment was to determine if there are any differences between the osmolalities, the no-weight-changes of osmolalities, and the water potentials of potato cores in different solutions of different solutes. The percent weight change of the potato cores was calculated through a “change in weight” method. The potato core’s weight was measured before and after they were put into different concentrations of a solute for 1.5 hours. In our experiment, there were no significant differences from the osmotic potentials of our results and the osmotic potentials of other scientists work. Ending with chi square values of 2.17 and 2.71, and p values of 0.256 and 0.337, concluding that there is no difference in water potentials of potato cores in different solutions of different solutes at varying concentrations.

The aim of this investigation was to determine the effect of ethanol on the membrane permeability using Beta vulgaris. Beta vulgaris contains red pigments called betalain sequestered in vacuoles. The cell membrane is generally impermeable to betalain as this pigment is relatively large and cannot pass through the membrane by diffusion. (123HelpMe.com, 2015) However, by increasing the permeability of the cell membrane, betalain can leach out of the cell and colour the liquid red. The colour intensity of the solution due to leakage of betalain is proportional to the membrane permeability. To quantify the colour intensity, the light absorbance of the solutions containing a Beta vulgaris cube were measured by a spectrophotometer. These measurements were used to analyse the membrane permeability. (Flinders University, 2015)