Investigating Osmosis in Potato Cells Planning: Aim:- To investigate the effect of different concentrations of sucrose solution, on potato cells Osmosis:- Osmosis is the passage of high water concentration through a semi-permeable membrane to a region of low water concentration, i.e. the passage of water. Explanation of osmosis For osmosis to occur there must be; semi-permeable membranes are very thin layers of material (cell membranes are semi-permeable) which allow some things to pass through them but prevent other things from passing through. Cell membranes will allow small molecules like Oxygen, water, Carbon Dioxide, etc. to pass through.
Investigate the Osmotic Point of Equilibrium in a Potato The following Passages are information which I have managed to find when researching the topic of Osmosis: - The cell membrane controls the movement of substances going into and out of the cells. The cell therefore controls the Chemical composition of the internal environment of the cell. It does this in two ways; Passive Process - this does not require energy Active Process - this does require energy to occur This works in principle which diffusion in which molecules and ions in a solution move from an area of high concentration to an area of low concentration resulting in the equal distribution of molecules. Cells membranes are selectively or partially permeable, this means moving the membrane allows certain molecules to pass through it moving freely down the concentration gradient but not others. Osmosis The cell membrane is partially permeable in that it allows some molecules to diffuse rapidly but slows the passing of others.
Experiment to Investigate Osmosis in Potatoes The aim of this experiment is to investigate the movement of water in and out of plant cells. The cells chosen for study will be taken from potato tubers. Firstly I will explain what osmosis is. Osmosis is the passage of water from a region of high water concentration through a semi permeable membrane to a region of low water concentration. This definition contains three important statements: a) It is the passage of water through a semi permeable membrane b) It is the passage of water from a region of high water concentration c) It is the passage of water to a region of low water concentration.
By doing this I will receive more accurate results and therefore draw up a more accurate conclusion. I will also use 20 ml of each solution and of tap water. The potato cylinders will then be left for 15 minutes. When the cylinders are removed I will clean them with a paper towel, to remove excess moisture, and then re-weigh them. Prediction For this investigation, I think the lower the concentration of the
The net (overall) result is that water enters the cell. The cell is likely to swell up. · If the medium is exactly the same water concentration as the cell there will be no net movement of water across the cell membrane. Water crosses the cell membrane in both directions, but the amount going in is the same as the amount going out, so there is no overall movement of water. The cell will stay the same size.
If a cell were put in a hypotonic solution, osmosis will cause water to move through the cell membrane into the cell. A solution is hypertonic if its concentration of dissolved substances is greater than the concentration inside the cell. If a cell were placed in a hypertonic solution, it would lose water. All particles that pass through the plasma membrane by the process of diffusion do not require energy, so their movement is called passive transport. The transport of materials against a concentration gradient requires energy, so it is called active transport.
A solution that has a lower solute concentration than is present in cells is said to be a hypotonic or hypo-osmotic solution. In this case, excess water flows into the cells and the cells swell. These cells may eventually rupture or burst open. This process is called lysis. Although we simplify osmolarity problems by using the % of a solute to
Investigating Osmosis in Potatoes Aim: Investigate the movement of osmosis through a selectively permeable membrane, in this case potato. Introduction: Osmosis is the movement of water through a semi permeable membrane. The water passes from an area of high concentration to an area of low concentration, until the two concentrations are equal in concentrations of water. Many cell membranes behave as semi permeable membranes, and osmosis is a vital part in the movement of liquids in living organisms, for example, in the transport of water from the soil to the roots in plants. If a cell is in contact with a solution of lower water concentration than its own contents, then water leaves the cell by osmosis, through the cell membrane.
The increased pressure of water inside the vacuole is called Turgor pressure. Then the cell becomes turgid. Plasmolysis is the opposite of turgor. This happens when plant cells may be placed in a less concentrated solution of water, although this is very unlikely to happen in nature. Water passes out of the vacuole, the cytoplasm, the cell membrane and the cell wall and into the solution outside the cell.
Cells placed in distilled water take up water by osmosis. This happens because the cell contains dissolved chemicals and therefore has a lower water potential than the distilled water surrounding it. As there are more water molecules outside the cell, more go in to the cell than out of it. The net movement of the water molecules is into the cell, and the cell will increase in mass. Eventually the cell stops taking up water, even though the concentrations inside and outside are not even.