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Investigation of osmosis and cell structure
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Recommended: Investigation of osmosis and cell structure
In this experiment we took dialysis bags and filled them with various sucrose solutions and put them in water over a period of about 90 minutes to look at the osmosis in each bag and the tonicity of each environment the bags were in. We also took potato pieces and submerged them into various sucrose solutions to determine the ideal state of tonicity for plants and the osmosis that occurred over a period of time. The final results for the first exercise was that 0.8M sucrose solution gained the most mass and that it was hypertonic to its environment. The overall results for exercise 2 was that 1.0M sucrose solution lost the most amount of mass and was hypotonic to its environment.
Introduction
In this lab we tested osmosis through a semi permeable membrane using dialysis bags (SCC Science Division, 2014). We also looked at osmosis in living cells of potatoes. When water is moved through a semi permeable membrane that is called osmosis. Passive transport is when molecules move with the concentration gradient across the membrane with no cellular energy used. Osmosis and diffusion are examples of passive transport. There is also active transport which is when molecules move against the concentration gradient and uses energy in the form of ATP (Urry, Cain, Wasserman, Minorsky, Jackson, & Reece, 2014). There are three types of conditions that deal with osmosis that will be found in this experiment: isotonic, hypertonic, and hypotonic solutions. Isotonic is when the concentration of a solute is identical outside of the cell and inside of the cell. Hypertonic is when the concentration of solute is higher outside of the cell than inside of the cell. Hypotonic is when the concentration of a solute is less than the solutions outside the c...
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...again we would try to make sure that one of the potato pieces was in a completely isotonic environment (SCC, Science Division, 2014).
References
Urry, L., Cain, Wasserman, Minorsky, Jackson, & Reece. (2014). Membrane Transport and Cell
Signaling. In Campbell biology in focus (pp. 94-102). Boston: Pearson.
Diffusion. (2000, August 1). Retrieved October 15, 2014, from http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/diffus.html Surry Community College. (2014). Osmosis and diffusion Part 1. In SCC Science Division (Ed.),
Lab manual-Biology 111-General Biology I (pp. 35-37). Dobson, NC: Surry Community College.
Lodish H, Berk A, Zipursky SL, et al. Molecular Cell Biology. 4th edition. New York: W. H.
Freeman; 2000. Section 15.8, Osmosis, Water Channels, and the Regulation of Cell Volume. Available from: http://www.ncbi.nlm.nih.gov/books/NBK21739/
The Effect of Solute Concentration on the Rate of Osmosis Aim: To test and observe how the concentration gradient between a potato and water & sugar solution will affect the rate of osmosis. Introduction: Osmosis is defined as, diffusion, or net movement, of free water molecules from high to low concentration through a semi-permeable membrane. When a substance, such as sugar (which we will be using in the experiment we are about to analyse), dissolves in water, it attracts free water molecules to itself, and in doing so, stops them from moving freely. The effect of this, is that the concentration of (free) water molecules in that environment goes down. There are less free water molecules, and therefore less water molecules to pass across a semi-permeable membrane, through which sugar molecules and other molecules attached to them are too big to diffuse across with ease.
Osmosis Experiment Planning Aim: The main subject that I will be planning to investigate is the effects of a concentrated sucrose solution on potato cells on the basis of the Osmosis theory. Background knowledge: The plant cell and its structure To understand osmosis in detail I will need to explain the plant cell (which is the cell included in the osmosis experiment) and its cell membrane. Below I have a diagram of a plant cell: [IMAGE] Osmosis is about the movement of particles from a higher concentrated solution to a lower concentrated solution to create an ethical balance via a partially or semi permeable cell membrane. Osmosis in simple terms is the exchange of particles between the cytoplasm inside the cell and the solution outside the cell. What makes this exhange is the partially permable cell membrane.
== == = Osmosis is defined as 'the movement of water molecules from an area of high water concentration to an area of low water concentration, across a semi-permeable membrane' (Collins, 1999). A semi-permeable membrane is a membrane that partially allows liquid to pass through. In the case of the experiment I am carrying out, the potato chips have small holes in their membranes, which only lets some water molecules flow in and out of the solution and potato chips depending on the concentration of both.
The experiment is aimed at giving a better understatement of osmosis process and the different conditions in which osmosis occurs.
molecules go in and out of the cell. There is no net movement of water
Investigate the Osmosis of Potato Cells in Various Salt Solutions. Introduction I have been asked to investigate the effect of changing the concentration of a solution on the movement of water into and out of potato cells. I will be able to change the input of my experiment. The input variable is the concentration of the solution.
In life, it is critical to understand what substances can permeate the cell membrane. This is important because the substances that are able to permeate the cell membrane can be necessary for the cell to function. Likewise, it is important to have a semi-permeable membrane in the cell due to the fact that it can help guard against harmful items that want to enter the cell. In addition, it is critical to understand how water moves through the cell through osmosis because if solute concentration is unregulated, net osmosis can occur outside or inside the cell, causing issues such as plasmolysis and cytolysis. The plasma membrane of a cell can be modeled various ways, but dialysis tubing is especially helpful to model what substances will diffuse or be transported out of a cell membrane. The experiment seeks to expose what substances would be permeable to the cell membrane through the use of dialysis tubing, starch, glucose, salt, and various solute indicators. However, before analyzing which of the solutes (starch, glucose, and salt) is likely to pass through the membrane, it is critical to understand how the dialysis tubing compares to the cell membrane.
If the concentration of sucrose increases, then the mass of the potato will decrease. However, if the concentration of the solution in the beaker is less than that of the potato (such as distilled water), then the mass of the potato will increase. So, as the concentration of sucrose increases the rate of osmosis increases.
The data presented in this table supports the conclusion of Purdy et al. (2005) that the inclusion of cholesterol to the CHO cell membranes will result in significant changes to the membrane, confirming the established function of cholesterol as a regulator of membrane fluidity.
Osmosis in Carrots Background Osmosis is the diffusion of water from a dilute solution to a more concentrated solution through a partially permeable membrane, which allows the pass of water molecules but not solute molecules. [IMAGE][IMAGE][IMAGE][IMAGE][IMAGE][IMAGE][IMAGE][IMAGE]If a cell is placed in a less concentrated solution water enters because the less concentrated solution will have a high concentration of water than the inside of the cell. Once the cell takes in maximum water the cell becomes turgid. If the cell was to be placed in a high concentrated solution, water would leave the cell because the cell would contain a low concentrated solution. So in the low concentrated solution there will be a high concentration of water and in the high concentrated solution there will be a low concentration of water.
-The cells in the body will increase because osmosis causes molecules to move from a less concentrated solution to a more concentrated solution.
Most cell membranes are like that, being permeable to water and some solutes only. Osmosis is therefore the diffusion of water through a partially permeable membrane. The basic principles of diffusion apply here.
Activity 3: Investigating Osmosis and Diffusion Through Nonliving Membranes. In this activity, through the use of dialysis sacs and varying concentrations of solutions, the movement of water and solutes will be observed through a semipermeable membrane. The gradients at which the solutes NaCl and glucose diffuse is unproportional to any other molecule, therefore they will proceed down their own gradients. However, the same is not true for water, whose concentration gradient is affected by solute ...
Osmosis in Potato Tubes Osmosis: Osmosis is the movement of water molecules through a semi-permeable membrane from a high concentration to a low concentration. Diagram: [IMAGE] [IMAGE] Aim: To see the effects of different concentration of sugar solution on Osmosis in potato tubes. Key factor: In the investigation we change the sugar solution from: 0%-10%-20%-30%-40%-50% this is the independent variable; the dependant variable is the change in mass. Prediction: I predict that all the potato tubes in pure water or low concentration sugar solution will swell because water enters their cells by osmosis.
Osmosis is the passage of water molecules from a weaker solution to a stronger solution through a partially permeable membrane. A partially permeable membrane only allows small molecules to pass through, so the larger molecules remain in the solution they originated in. Solute molecule [IMAGE] [IMAGE] Water molecule [IMAGE] The water molecules move into the more concentrated solution. When water enters a plant cell it swells up. The water pushes against the cell wall and the cell eventually contains all that it can hold.