A Basic Understanding of Diffusion and Osmosis The purpose of this lab was to have a basic understanding about concepts diffusion and osmosis. In this lab we had dialysis tube as a cell membrane of cell, which lets small particles pass through it nbsp; Diffusion and osmosis video Khan Academy , osmosis , and concentration gradients and why these are important to cells.
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Don 39;t study it Osmose it! Knowledge Diffusion. Free; Offers In-App Purchases. This includes flashcards, practice questions, videos, etc.
Osmosis also keeps you on your toes by sending quot;push questions quot; to your mobile devices nbsp;. Osmosis Essay Examples Kibin in a Potato. An Analysis of Osmosis and Diffusion in Biology. Diffusion is the movement of particles atoms, ions or molecules from a region in which they are in higher concentration to regions of lower concentration.
A good example of diffusion is food colouring. If you place a drop of red food colouring in a beaker of water eventually the entire beaker of water will have a nbsp; Biology Coursework : The effects of Osmosis on a potato chip in : Effect of Sugar Solution on Potato ChipsPlanningBefore planning the experiment, I will research osmosis , so that I can make predictions. This will help me to discover how to make this investigation fair and safe.
If a concentration gradient has been established across a membrane, the permeable solute will diffuse across the membrane: Your answer was: nbsp; Osmosis potato lab report Gravy Anecdote help online. Activity 2: Eggs and Osmosis. Formal lab report using each part of the scientific method. Use the following table for data if you were unable to complete the lab This simple osmosis experiment is a great way to teach any new biology student the gist of diffusion and the process of osmosis , regardless of.
Leaving Cert. Biology Osmosis - The movement of water molecules from a region of high concentration to a region of low concentration; Diffusion The passive movement of particles from a region of high concentration to a region of low concentration; Turgor The normal rigid state of fullness of a cell as a result of the pressure of the contents of nbsp; Osmosis and diffusion lab report. Diffusion , Osmosis and Active , or lab reports. Writers with varied academic experience and fields of nbsp; across.
Hydrostatic pressure pressure potential usually is positive but can be negative such as in xylem where the water is under tension so the pressure potential returns a negative value. In plant cells the force of the water pushing against the cell wall creates a positive pressure potential causing the cell to become turgid. If we return to the sucrose experiment and let it continue, the bag will eventually become turgid. If the bag is suspended in fresh distilled water, it will increase in mass as it gains water. Because the bag acts like a cell wall, it cannot stretch further and pressure begins to build up eventually rising out to cancel out the solute potential.
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Every cell in a plant has a lipid bi-layer surrounding its content. So how does water get into a cell to affect its water potential? Water can sometimes find gaps in-between various molecules embedded in the surface such as glycoproteins. Also cells have protein lined pores that selectively allow some compounds through. When a cell is in water of the same water potential as itself, there is no net water movement, even though water molecules are moving in and out of the cell. The two sets of water are said to be isotonic. If there is no net water movement into cells, then they will not increase in mass.
If we were to replace the surrounding cells with a solution of sucrose, you can test which solution will not cause the cells to increase in mass. If you know the water potential of the solution then you can find the water potential of the cell.
When the external water potential of the cell is less negative than the cell, more dilute, water flows into the cell. In this case the outside solution is said to be hypotonic. The cell sap becomes diluted, and the volume begins to expand and push against the cell wall. A pressure potential develops and eventually causes the rate of osmosis to cease. The cell walls help prevent the cell from haemolysing and destroying the cell.
The cell is now described as turgid. Being turgid does not cause damage to the cell and it will eventually return back to its normal size. This case is most likely to happen during the experiment when the solvent used has a molarity of 0. In these cases the potato slices would have put on their maximum weight. The reverse can also happen. If the surrounding solution is more negative called hypertonic then the water flows out of the cell. The cell sap would become more concentrated and the cell membrane would pull away from the walls, apart form where cytoplasmic connections occurred.
Cells in this condition have become flaccid. Cells that are flaccid are not damaged in the long run and return to normal once they receive water.watch
Investigate Osmosis :: GCSE Biology Osmosis Coursework
This case will probably occur at molarities of 1. The slices in this case would lose weight. The baking potato and the sweet potato have different compositions and these factors will determine the outcome of the experiment because the amount of impurities in the potato will govern its water potential.
Potatoes have 76g of water for every grams, whereas sweet potatoes only have 70g of water every g. This already shows that baking potatoes have more water and therefore a less negative water potential than the drier sweet potatoes. The aim of this preliminary experiment was to best determine how to carry out the method in the real experiment, not to gather results. I only used one type of potato, the baking potato, to test the method since the sweet potatoes would not show another way of carrying out the practical.
My method was to rinse all the equipment out with distilled water three times. Then I cut a cylinder out of the baking potato using a borer. Then I cut thirty-six slices of roughly the same width using a scalpel on a white tile, boring out more cylinders when needed. I then labelled six test tubes with 0.
A Biology Coursework: Osmosis
I then put 10 ml of distilled water into the 0. Once this is complete, you need to re-rinse the burette with distilled water. Then, put 10 ml of 1. Shake each test tube well, covering it and then inverting it three times. You should now have sucrose concentrations equal to that of their labels.
Record the combined mass of six potato slices and place them into the 1. After three minutes, drain away the solution and dry the potato slices gently on some tissue, then reweigh. Take another six slices and do the same for each of the different strength solutions of sucrose, taking six fresh slices every time. The equipment used were: digital scales, baking potato, borer, sucrose 1.
I feel that the results generally went well, except the last value which was a bit more extreme than I thought it would be. While I was carrying out the practical I became aware that when the potato slices were placed into the test tubes they did not always show the same surface area, something which might affect results since the amount of contact between cells and water determines how much osmosis takes place, more surface area, more area for water to diffuse into cells.
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In a bid to correct this, I will use a mounting needle, so that as much surface area is in contact with the water. Also I might leave the potato slices in their test tubes for five minutes so that as much water as possible can enter the cell. Also I will repeat the experiment in total twice more to improve reliability three times baking potato, three times sweet potato. In addition, I could also take the mean temperature of the room, because temperature differences have an affect on proteins and their hydrogen bonds protein water channels , or I could submerge the test tube containing solutions into a water bath at a.
This would be a better temperature, as it would be more stable than fluctuations in the room temperature. Place a thermometer in the room away from sunlight and record its temperature every five minutes. The thermometer is there to get a mean temperature reading throughout the practical to allow for variances which could affect the protein pores in the potato cells. The thermometer must be out of sunlight because that could give a biased reading. Rinse out all components not electronic like the stop clock or.
Rinsing the equipment three times dilutes impurities by a greater factor than just doing it once.
Using a borer cut out a whole cylinder of potato out of the baking potato. Using a white tile as a backboard, cut slices of potato, taking more cylinders out of the potato then needed, of roughly the same width using a scalpel. Take care with the scalpel as it is much sharper than a normal knife. The white tile will protect the surface you are working on.
The slices will be sufficient for the entire experiment. The remainder will allow for two extra repeats. The potato slices must be the same width and diameter to have the approximately same surface area, this is a primary factor over differences in mass as they are generated into percentages later on. The surface area will affect how much water can enter the total volume of the potato slice. You must cover then shake each test tube to mix up the sucrose and water, this will give an even water potential.