An investigation of the glucose concentration of the cell sap in potato cells In this experiment I intend to investigate the effects of osmosis on potato cells. Specifically, I intend to use my knowledge of osmosis to investigate the glucose concentration of the cell sap in potato cells. Osmosis is a method by which water levels on either side of a semi permeable membrane may balance themselves. It occurs between regions of high water concentration and low water concentration. As it is a special method of diffusion exclusive to water, it also allows dilute and concentrated solutions to balance their strengths.
This usually results in equilibrium. When the plant cell is full of water, the weight increases and we say that it is turgid. The cell wall prevents the cell from bursting. Cell in a strong sugar solution When a plant cell is placed in a strong sugar solution, there is more water in the cell then in the surrounding solution, so water is drawn out by osmosis. This makes the cell decrease in weight and it becomes flaccid... ... middle of paper ... ... sure that on my behalf, my results are accurate.
The transport of materials against a concentration gradient requires energy, so it is called active transport. Aim Our aim was to find out how sugar solution strength affects osmosis, we did this by doing an experiment and then got the results. The results are as expected the 2m solution has made the potato pieces in the jar shrink. The experiment has proven that the stronger the solution is the more it affects the rate of osmosis in a semi-permeable membrane. The aim that we had was proved right and sought out to investigate osmosis in a more detailed way for us to find out more information about it.
This membrane is called a partially permeable membrane. The amount of water inside a cell is called water potential. Turgor is the name given when osmosis takes place between the cytoplasm and the solution outside the cell. This happens when a plant cell is placed in a high concentrated solution of water, water then passes through the cell wall, the cell membrane, and the cytoplasm and into the vacuole. The increased pressure of water inside the vacuole is called Turgor pressure.
Osmosis The cell membrane is partially permeable in that it allows some molecules to diffuse rapidly but slows the passing of others. The glucose molecules try to diffuse to the outside but cannot get through the membrane because the pores are too small. The water molecules diffuse trough the pores down the concentration gradient. This membrane- controlled diffusion of water molecuse is controlled by osmosis, it can works both ways so that it can pass into and out of the cell. Osmosis and Diffusion If water is withheld from a flowering plant, the flowers wilt.
-From Encarta 2001 In osmosis, a solvent (often water) moves from a region of low concentration to a region of high concentration through a semi-permeable membrane. Here, water molecules diffuse into the concentrated sugar solution because the water molecules are small enough to move through the membrane. The larger sugar molecules are unable to move through the membrane into the water solution. Osmosis will stop when the two solutions reach equal concentrations on either side of the membrane[IMAGE] . In the investigation I will be doing, it is osmosis in plant cells
Investigation of Osmosis Aim: - To investigate the effect of varying the concentration of sugar solutions on the effect of osmosis between the solution and a potato chip cells. Apparatus: - Potatoes Watch Sugar solutions (DI, 0.2, 0.4, 0.6, 0.8, 1Molar) Distilled water Mass balance Knife Measuring cylinder 6 petri dishes Ruler Prediction: - I think that the lower the concentration of the sugar solution in the petri dish the larger the increase of the mass of the potato will be. This is because the water molecules pass from a high concentration to a low concentration of water molecules through a semi-permeable membrane. The chips in higher water concentrations will have a larger mass than in higher sugar concentrations. My graph may look like this: [IMAGE] I think this is going to happen because of the following scientific knowledge: Scientific Knowledge: - Osmosis is the movement of water molecules to a lower concentration of molecules through a semi-permeable membrane.
It is the movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration until equilibrium is reached. This means that only water molecules can pass through the partially permeable membrane due to it being small enough to fit through. Bigger molecules such as glucose would not be able to get through. Also Osmosis makes plant cells swell up or turn turgid when the cell is placed in a solution containing a higher concentration of water, or shrivel up when placed in a low concentration of water. Apparatus.
Investigating Osmosis Introduction Definitions - Osmosis is the movement of water molecules from where they are at a high concentration to where they are at a lower concentration through a selectively permeable membrane. A selectively permeable membrane is one which allows only molecules of a certain size through. [IMAGE] This very basic diagram shows osmosis occurring between sugar solutions and water in visking tubing and beakers. The bag expands because the water moves from the beaker where it is at a higher concentration through into the tubing where it is at a lower concentration. Example of osmosis - Osmosis is the way in which plants absorb water (and get their minerals).The cell walls in the root hairs are semi-permeable.
If a plant cell is placed in pure water, water outside the cell will flow into the cell by osmosis as the interior of the cell has a lower water potential than the pure water. The reason why the interior has a lower water potential is because the cytoplasm has substance like glucose dissolved into it. As more and more water flows into the cell the cell becomes more and more rigid. Eventually the cell becomes turgid and this is when the cell will not accept anymore water as the water potential inside and outside now balanced. If we replicated this with an animal cell it would burst as water would enter osmotically and then the cell would become rigid and there would be no support from a cell wall, and thus the cell will burst.