...Diffusion and Osmosis Diffusion is the passive movement of molecules or particles along a concentration gradient, or from regions of higher to regions of lower concentration. Osmosis is a type of diffusion. This is the diffusion of water through a selectively permeable membrane (chooses what comes in and what goes out) from a region of higher water potential to a region of lower water potential. Water potential is the measure of free energy of water in a solution. Unlike diffusion, osmosis requires ATP to move the particles across the membrane. Hypothesis: In both experiments diffusion and osmosis will occur between the solutions. In experiment 1A the tube of glucose/starch will absorb the iodine solution in the cup. In experiment 1B the tube of distilled water will lose weight, and the tube of glucose will gain weight. The purpose of the experiments is to differentiate which test was diffusion and which was osmosis. Materials: Experiment 1A: Plastic Cup, Plastic Pipet, Iodine-Potassium Iodide, Deionized Water, Glucose Paper Strip Experiment 1B: (3) 15 cm pieces of Dialysis Tubing, beaker, 15 cm piece of white thread, 80% Glucose, 2% Starch, Plastic cup, 10% glucose, 15 cm blue thread, distilled water, 15 cm red thread, 20% glucose Procedure Experiment 1A: First cut a 15-cm length of dialysis tubing. Place the dialysis tubing in a beaker of distilled water and allow it to remain in the beaker for 1 minute. Open the dialysis tube by rolling it in between thumb...
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...Diffusion and Osmosis: A Full Analysis on the Concentration of Solutes and the Molecular Weight of Substances in a Dialysis Tubing and Potato Experiment Alejandro Gonzalez October 30, 2012 Biology 1500 Professor Raja Abstract The purpose of the diffusion and osmosis lab experiments is to determine the contents present before and after leaving a dialysis tubing in a beaker of solution and to test water potential by determining the percent change in mass of potatoes when left in different concentrations of sucrose in numerous beakers. In the first experiment, what occurred was that we put contents into the dialysis tubing and in a solution in a beaker and we were to set the tubing in the beaker for a set amount of time and see what contents are present in the beaker and in the dialysis after the amount of time. In the second experiment, we were to test if a mass change would occur if we set potatoes in different concentrations of sucrose. My alternate hypothesis in the first experiment with the dialysis tubing was accepted due to the fact that glucose and sodium sulfate diffused across the pores of the tubing, but starch and protein could not be. My alternate hypothesis in the second experiment was also accepted due to the fact that there was a mass change in the potatoes when put in different concentrations of glucose. Introduction Diffusion and osmosis are two terms that actually coincide with each other in the big picture and in this particular set of experiments...
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...Brad Sanford Bio 1120 Section 6 September 17, 2013 Partners: Dominique & Carleigh Lab #2: Osmosis & Diffusion Introduction Diffusion is the movement of molecules from a high concentration gradient to a low concentration gradient. This can occur in gases, liquids, and solids. Osmosis is a type of diffusion that allows water molecules to move through a semipermeable membrane freely by way of passive transport. During osmosis a semipermeable membrane will allow small water molecules to pass through freely without any help but larger molecules like proteins will not move through the semipermeable membrane without active transport. Active transport requires a chemical energy like ATP (adenosine triphosphate) to help the larger molecules move through the cell’s membrane.(Krane) When describing high and low concentrated solutions, it is useful to understand the terms hypertonic, hypotonic, and isotonic. A hypertonic solution has a higher concentration of solutes compared to a lower concentrated solution as water will move out of the solution (Dehydration). A hypotonic solution has a lower concentration of solutes compared to a solution with a higher concentration of solutes and water will move into the solution (Swelling). In a isotonic solution the solutes are at an equal concentration and there is no movement of the water. In this lab, two experiments were performed. The first one uses a small plastic bag closed up and filled with cornstarch and distilled water...
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...In today’s lab we were able to get a hands on look at the osmosis and diffusion process as well as analysis the nutrients in food. We were separated into groups chosen by the Teachers Assistant and began our lab. There was a brief lecture with notes and what we would be looking forward to within the lab. We were given more information on what osmosis and diffusion were. Further into the discussion we learned about controls and variables. As we finally began the experiment we needed to make sure we had the required items such as the beakers, testing strips and the chemical solutions. From there we were able to go over the instructions and carefully do the assigned tasks. For our first experiment which was the Osmosis and Diffusion lab. We needed...
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...The purpose of this experiment was to demonstrate how diffusion and osmosis moves across a dialysis membrane. The sub-purpose was to determine if the sucrose solution, that was in dialysis tubing would leak into the distilled water. The hypothesis states that if a sucrose solution, in dialysis tubing, is placed into a beaker filled with distilled water the net movement of sucrose will be into or out of the dialysis bag. The null hypothesis states that if the sucrose solution in a dialysis bags mass may change after taking it out of the water each time to be weighted between each 15-minute increment 5 different times. After 15, 30, 45 and 60 minutes it can be concluded that weighing the sucrose solution in the dialysis bag increased in weight after each increment. Keywords: Diffusion, Osmosis, Dialysis bag, Sucrose solution, Distilled water Introduction...
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...Marisa M Souza AP Biology Mrs.Therrien October, 6, 2015 Diffusion and Osmosis Exercise 1A: Diffusion In our diffusion experiment glucose is leaving the bag and Iodine-Potassium-Iodide or IKI is entering the bag. The change in color within the bag indicates the presence of glucose. The IKI moved from the beaker into the dialysis bag, this resulted in a change of color to black within the bag. This made the concentration within the bag equal to the concentration outside the bag. The glucose solution moved out of the bag making glucose present in the beaker. The glucose moved to make the solute concentration inside and out equal. If the initial and final % concentration of glucose and IKI for in the bag and in the beaker were given they...
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...Sonora Schueneman Dr. Kemp- Hailee Nerber Bio 111- 551 19 September 2017 Osmosis and Diffusion Across a Plasma Membrane-Lab 2 Week two in the lab consisted observing a constructed experiment involving osmosis and diffusion across a semi-permeable membrane. This allowed myself to formulate a hypothesis stating, the four pipets of cooked starch and amylase will diffuse through their dialysis bag into the beaker containing 2/3 water and four pipets of Lugol’s solution. Thus being stated, the null hypothesis would be, the four pipets of cooked starch and amylase will not diffuse through their dialysis bag into the beaker containing 2/3 water and four pipets of Lugol’s solution. In order to test our hypothesis, I set up a control beaker (Beaker...
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...Diffusion is defined as the random movement of molecules from an area of higher concentration to areas of lower concentration. Osmosis is a special type of diffusion in which water moves from high to lower concentration through a selectively permeable membrane. If for some reasons two solutions have same level of concentration no movement take place and such solutions are called isotonic. If the solutions have different levels of concentration then the area with higher concentration is called hypertonic and the area with lower concentration is called hypotonic. This experiment was conducted to observe the osmosis process. In this experiment dialysis tubbing served as the permeable membrane. The weight of the dialysis bags is taken one time before putting them into the solution and once after soaking the bag into another solution for about the hour. The weight of the bag determined the movement of the molecules from higher to lower concentration. Hypothesis: for this experiment three hypothesis were made: 1. For test one it was expected that the water molecules will enter the dialysis bag 2. For test two it was expected that the water molecules will move out from the dialysis bag 3. For test three it was expected that the water molecules will move into the dialysis bag Material:...
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...Diffusion And Osmosis Introduction: There are several valuable aspects of this lab that must be understood before it is conducted. The first of these concepts is called diffusion. Molecules are constantly moving and as they are moving they tend to move from areas of higher concentration to areas of lower concentration. Diffusion can be defined as the net movement of molecules from higher to lower concentrations. One example, of diffusion is when an item like perfume is opened in a room. Shortly after it is opened the smell can be detected throughout the entire room. Diffusion can occur through a membrane such as that of a cell which explains how something can enter the cell. One special type of diffusion is called osmosis or the diffusion of water. Osmosis describes how water moves through a membrane from areas that have high water potential to areas that have lower potential. Water potential is defined as the measure of free energy of water in a solution. Biologists use this term to help describe why water moves from one area to another. Water potential can be affected by two major aspects pressure and the amount of solute. Water potential can be calculate by the pressure potential added to the solute potential. In order to calculate the solute potential one must multiply the ionization constant, the molar concentration, the pressure constant, and the temperature. When looking at a solution one can categorize it into several different relationships based...
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...Kristina Eskola BL 1020 L01 Diffusion and Osmosis Lab Report (Dialysis) Introduction: Dialysis Tubing is a membrane made of regenerated cellulose fibers formed into a flat tube. If two solutions containing dissolved substances of different molecular weights are separated by this membrane, some substances may readily pass through the pores of the membrane, but others may be excluded. We will be investigating the selective permeability of the tubing to reduce sugar, glucose, starch, and iodine potassium iodide. We will test this by placing a solution of glucose and starch into a dialysis tubing bag and then place this bag into a solution of iodine potassium iodide (I2KI). Prediction: The I2KI solution will turn blue when adding Benedict’s reagent. Hypothesis: The solution of water and I2KI will be the most permeable because they will mix and react with Benedict’s reagent and the heat so the cell membrane only allows certain molecules to enter and leave the cell Materials and Methods: In the experiment we will be using two tests. In the first test, we will be using I2KI to test for the presence of starch. When I2KI is added to an unknown solution, the solution will turn purple or black if starch is present. If there is no starch in the solution, it will remain pale yellow. In the second test we will be using Benedict’s test for reducing sugar. When Benedict’s reagent is added to an unknown solution and the solution is heated, it will turn green, orange or orange-red...
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...Investigating Osmosis in Potatoe Tissue To find out how the concentration of sucrose solution affects the rate of osmosis in a potato and what happens to the length and mass of the potato. What is osmosis? Osmosis is the movement of the water molecules across a partially permeable from a region of high water concentration to a region of low water concentration. Osmosis is a special case of diffusion The biochemical process in living cells always takes place in a solution. A solution is made up of a solvent (the dissolving fluid) and solute (the particles dissolved in the solvent). In living organisms, the solvent is water and the solution is called aqueous solution. Living cells are separated from their surroundings by the partially permeable cell surface membrane. The contents of the cell, the cytoplasm, are one aqueous solution and the surroundings of the cell, for example pond water, is another aqueous solution. If the two solutions do not have the same concentration of various substances, molecules may move away from one to the other by diffusion, if the membrane is permeable these substances. To summarise osmosis: The diffusion of water molecules, down a water potential gradiant across a partially permeable membrane. Cells and osmosis A cell is surrounded by a partially permeable membrane, and water may cross the membrane easily. If cell is placed in a solution of lower water potential, water leaves the...
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...In our lab, we were able to witness the process of osmosis and diffusion through dialysis tubing, starch, glucose, iodine, and water. The reason we chose to use these materials is because the dialysis tubing could act as a selective permeable cell membrane to view which molecules are able to pass through and which weren’t. We used the starch, since it is a polymer, and found out that it could not pass though the membrane. We used the glucose, which is a monomer, and found that it was easily able to go into a state of equilibrium with the water. The monomer was able to pass through the dialysis tubing due to its small size and the polymer was not due to its large size. This was what we had predicted in our hypothesis except for the fact that although the glucose did pass through the membrane it did not completely pass through only some of it to create equilibrium. In the starch and iodine solution it was the iodine which was allowed to pass thought the starch was not able to due to its large size further explaining why the water had eventually turned almost clear again compared to its brown looking initial state and the inside of the membrane had turned almost completely blue compared to the clear color it was before. When measuring the glucose both inside and out of the membrane we found that they both had some glucose in it, and although we could not visibly see the changes, it was noticed that the diffusion had occurred and since there was some glucose in each it is safe to...
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...Osmosis of Water Biology 105 Lab 3/22/11 Introduction Cells have kinetic energy, a source of energy stored in cells. This energy causes molecules to bump into each other and move in new directions. Diffusion is one result of this molecular movement. Diffusion is the random movement of molecules from an area of higher concentration to areas of lower concentration. Osmosis is a special kind of diffusion where water moves through a selectively permeable membrane that only allows certain molecules to diffuse though (Lab Manual 7e, 2010). Diffusion or osmosis occurs until dynamic equilibrium has been reached. This is the point where the concentrations in both areas are equal and no net movement will occur from one area to another. If two solutions have the same solute concentration, the solutions are said to be isotonic. If the solutions differ in concentration, the area with the higher solute concentration is hypertonic and the area with the lower solute concentration is hypotonic. Besides osmosis and diffusion, molecules and ions can be moved by active transport. This process includes the use of ATP (adenosine tri-phosphate) to drive molecules in or out of a cell. Active transport is generally used to move molecules against a concentration gradient, from an area of low concentration to an area of higher concentration of molecules. The purpose of this experiment was to show that osmosis of water thru plant stomata does not require energy (ATP)...
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...Diffusion and Osmosis Jeveen Edmondson Micah Martello Rachel Mitchell Katelyn Lanier Biology Lab 152_26 October 21, 2010 Introduction Purpose: To show the different effects concentration gradients have on diffusion and osmosis across a selectively permeable membrane. Diffusion is the movement of a molecule from an area of high concentration to an area of low concentration. Osmosis is the movement of H20 from an area of high concentration to an area of low concentration across a selectively permeable membrane. Selectively permeable means that the membrane is regulating the passage of some substances while preventing others from entering the cell. The rate of diffusion or osmosis depends upon different factors. Diffusion rates depend on temperature, concentration gradients, and the size of the molecule that is trying to pass. Osmosis will depend up whether the membrane is permeable to water. In this experiment, the rate of diffusion or osmosis is based on the concentration gradient. The differences in the concentration gradient will either make for an isotonic, hypotonic, or hypertonic solution. Isotonic means that the concentration is equal inside and outside of the cell. Hypotonic means that there is a higher concentration outside of the cell than inside, so molecules would move from outside of the cell to inside the cell; and hypertonic means that there is a higher concentration inside the cell than outside, so molecules would move from inside...
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... (4x, 10x, 40x) Part 2: 1) Repeat the same lab procedure as you did with soaking onion skin cells in tap water last day, but now using the onion and soaking it into saltwater. 2) Prepare a wet-mount slide for the onion skin cell done by your teacher. 3) Add iodine to the onion and place a cover slip on top of the onion. 4) Examine the slide under all magnifications and sketch Proper Biological Diagrams for each power. (4x, 10x, 40x) Hypothesis: If tap water is added to the onion skin cells then the water will absorb and swell up because, osmosis is occurred and it becomes completely inflated. If saltwater is added to the onion skin cells then the cells would wrinkle up and probably shrink because, once the onion is placed in salt solution, it will dehydrate since it’s hypertonic. The water would leave the cell by diffusion to get an osmosis balance. Observations: Quantitative Variables: * Amount of salt * Amount of water * What time you start the experiment * Where you place the onion * What temperature was the onion placed in before * How much iodine you drop on the onion skin * How long did you place the onion skin in either salt or tap...
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