The Effect Of Plasma On The Membrane Performance

Membranes are an important feature of plant cells and they act as a barrier that separates the interior of the cell from the external environment (Campbell et al., 2008). Each membrane layer is composed of a phospholipid layer, which is semi-permeable and possesses the ability to control the movement of diffusion. Within the centre of a cell, the vacuole that is responsible for storage and the maintenance of osmotic balance can be located. In this study, we are using beets to study these cellular structures. Beet is a plant whose cells contain a characteristic red pigment, called betacyanin. It is located in the vacuole, which is

This lab was performed to test the permeability of the cell membrane of a beet using various and extreme temperatures (high and low). The prediction of this lab is testing how much stress the cell membrane can withstand under different polarities and strengths of bonds using our understanding of the fluid-mosaic model. A spectrophotometer was used to calculate the absorbance of each variable after the beet was placed in each environment. When the lab was completed, the data stated that under each different reactant and condition the cell membrane showed multiple changes in tolerability of the beets.

The cell membranes are the utmost essential organelle that surrounds all living cells. Its purpose is to control what goes in and out of the cells and is accountable for the various other properties of the cells as well. The nucleus and other organelles also have membranes that are practically indistinguishable. Membranes are organised in a mosaic arrangement, comprised of carbohydrates, proteins and phospholipids. This can be seen in Figure 1. The objective of this indirect examination is to study the causes of various solvents and conducts on live beetroot cells. The reason why beetroot cells have been selected for this experiment is because they have a big membrane-bound central vacuole, as seen in Figure 2. The red colour anthocyanin, which provides the beetroot its bright colour is located in the vacuole. The cell membrane encloses the whole beetroot cell. The anthocyanin cannot leak out if the membranes stay unharmed. The red colour can escape if the membranes are hassled or broken.

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.

Repeated Trials: In procedure one, we tested diffusion on different sized cell models (gelatin with various volume and surface area wise). In procedure two, we tested cell models in different internal environments and similar external environments to find the effects on rate of osmosis. In procedure three, we used potato cells in different concentrated sucrose environments to test the effects on water potential on cells and osmosis.

The Transport of Substances Across the Plasma Membrane The plasma membrane or, the cell surface membrane, is made almost entirely of protein and lipid. The plasma membrane controls the movement of substances into and out of a cell. It is partially permeable so some substances cross more easily than others.

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.

The observation under the microscope of a cell of an onion skin soaked for 15 minutes in a 0.5 molar sucrose solution showed a cell membrane just beneath the cell wall. The cell wall had a rectangular shape. See diagram 3 for sketch. The cell and its surrounding were in an isotonic solution. The two solutions in the cell and out (0.5 molar sucrose solution) of the cell were homogenous. No net movement of water and change in the cell structure was observed. The components of the solute and solvent were evenly intermixed. The concentration of solute and solvent on either side of the cell membrane was equalized. Because the onion tissue didn’t get any water the cell was flaccid and nonturgid.

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)

The diffusion across a cell membrane is a process of passive and spontaneous net movement of small lipophilic molecules. The molecules move from a high concentration to a low concentrated region along the concentration gradient. The result being a point of equilibrium, this is where a random molecular motion continues but there is no longer any net movement. However, there are things that can affect the rate of diffusion, these being temperature, surface area, concentration, size of the molecule, permeability, diffusion distance and concentration difference. Osmosis is a type of diffusion as it is the movement of water molecules through a semipermeable membrane into a region of higher solute concentration. Equilibrium is reached when the solute concentration is equal on both sides. Water potential is measured in kiloPascals, it is the measuring of the concentration of free water molecules that are able to diffuse compared to pure water, which is 0 kilopascals. It is a measure of the tendency of free water molecules to diffuse from one place to another. The result being, the more free water molecules, the higher the Water Potential. However, Water potential is affected by two factors: pressure and the amount of solute.

All cells contain membranes that are selectively permeable, allowing certain things to pass into and leave out of the cell. The process in which molecules of a substance move from an area of high concentration to areas of low concentration is called Diffusion. Whereas Osmosis is the process in which water crosses membranes from regions of high water concentration to areas with low water concentration. While molecules in diffusion move down a concentration gradient, molecules during osmosis both move down a concentration gradient as well as across it. Both diffusion, and osmosis are types of passive transport, which do not require help.

are covalently attached to the surface of the membrane are loosely associated with the surface of the membrane may penetrate the membrane partially never interact with the surface of the membrane All of the following can cross the cell membrane by simple diffusion EXCEPT? O2 ethanol CO2 glucose All of the following factors affect membrane fluidity EXCEPT? temperature cholesterol cis/trans-configuration of double bonds all of the above affect membrane fluidity Which of the following is true when comparing facilitated diffusion to simple diffusion? facilitated diffusion does not occur down a concentration gradient, only simple diffusion does facilitated diffusion is faster than simple diffusion energy in facilitated diffusion is supplied

To study the effects of hypotonic, hypertonic and isotonic solutions on plant and animal cells.

Only uncharged, small, polar molecules, (such as water) and hydrophobic molecules, (such as oxygen, carbon dioxide) and lipid-soluble molecules (such as hydrocarbons) can freely pass across the membrane. All ions and large polar molecules (such as glucose) are not permeable to the membrane.