...Effects on rate of Osmosis across a selectively permeable membrane for varying starch solute concentrations and water mixed with Lugol’s Iodine The contents of this document pertain to the effect of particle (starch) concentration on the rate of Osmosis through a selectively permeable membrane made visible by the use of Lugol’s Iodine indicator. The results proved that the greater the concentration of the starch solute within the membrane, the greater the rate of osmosis and change in color of the solute due to an increase of Lugol’s Iodine diffusing into the membrane and reacting with the starch. Ruba Nizam 3/18/2014 Introduction The purpose of this lab is to test the rates of osmosis on a model of a selectively permeable membrane filled with varying levels of starch concentrations using dialysis tubing. This experiment will make it possible to see how particles move from an area of high concentration to an area of low concentration due to the use of Lugol’s Iodine indicator. According to Michael McKinley, osmosis is defined as the, “movement of water molecules across a membrane from an area of high water concentration to an area of lower concentration until equilibrium” (McKinley). Diffusion is related to the movement of particles from an area of high concentration to an area of low concentration. Osmosis and diffusion are both passive transports that do not require energy although osmosis is the diffusion of water (Balmer). These transport processes occur across...
Words: 2715 - Pages: 11
...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)...
Words: 756 - Pages: 4
...hypotonic solution in Solution A, the potato increased from 2.71 ± 0.01 grams to 3.01 ± 0.01 grams. Through osmosis, the water molecules moves from the solution into the potato cells’ semi-permeable membrane which exists across the concentration gradient in order to reach an isotonic state. This lead to the potato increasing in relative weight and size to its prior form. With my data’s evidence,...
Words: 570 - Pages: 3
...in a cell. It allows oxygen and carbon dioxide exchange in the lungs and between the bodies of intracellular fluid and cells. An example of this process is the diffusion of a smell in a room. Eventually dynamic equilibrium will be reached. This means that the concentration of the molecules carrying the smell will be approximately equal through out the surrounding enclosed area and no net movement of the molecules will occur from one area to another. Osmosis has to deal with the movement of water molecules. It is the diffusion or movement of water through semi-permeable membranes from a region of higher water potential (hypotonic solute) to a region of lower water potential (hypertonic solute). Water potential is the measure of free energy of water in a solution. The movement of water across the cell membrane depends on the concentration of solutes on both sides of the cell membrane. When water moves out of the cell, the cell will shrink. When water moves into the cell the cell will expand and possibly burst. Diffusion and osmosis are not the only processes responsible for the movement of ions or molecules in an out of cells. Active transport is process that uses energy from ATP to move substances through the cell membrane. Active transport moves a substance against its concentration gradient, that is to say from a region of low concentration to an area of higher concentration. Procedure 1A Obtain dialysis tubing that has been submerged in water. Tie off on of the ends to form...
Words: 1802 - Pages: 8
...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...
Words: 451 - Pages: 2
...Introduction Water can diffuse across the partially permeable membrane of cells depending on the concentration difference between the inside and the outside of the cells. You are going to look at the effect of different concentrations of sugar solutions on potato cells. By measuring the mass of the potato cylinders, you will be able to find out if water has entered or left the potato cells. Aim To find out what happens to the mass of potato cells when they are left in increasingly concentrated solutions. Hypothesis My hypothesis was that if the concentration of sugar where the water potential is higher than the water potential of the potato, the mass of the potato will increase. On the other hand, if they have similar water potential, the mass will not change. Variables Independent variable: concentration of sugar Dependent variable: change of mass of the potato before and after the experimant Controlled variable: temperature Apparatus • Potato • A 6mm Cork borer • Ruler • Scalpel • White tile • Sugar • Distilled water • Labelling pen • 50mL measuring cylinder • Weight balance • Stopwatch • Labels • Paper towel • 12 boiling tubes • Boiling tubes rack • Four 250mL beakers Methods 1. Measure 100mL of distilled water into a 250mL beaker. Label it “0% sugar solution”. 2. Measure 100mL of distilled water into a third 250mL beaker. Add 20g of sugar into it and stir until fully dissolved. Label it “20% sugar solution”. 3. Measure 100mL of distilled...
Words: 732 - Pages: 3
...nucleus being the yolk. Diffusion is the movement of cells from an area of higher concentration to an area of lower concentration. Osmosis is the movement of water molecules across a semi-permeable membrane. Diffusion and osmosis are important because they help with cellular respiration, which is how we stay alive. We conducted this experiment...
Words: 714 - Pages: 3
...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...
Words: 476 - Pages: 2
...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...
Words: 3633 - Pages: 15
...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...
Words: 1136 - Pages: 5
...includes selective transportation of molecules and cell-cell gratitude. The passive process of the plasma membrane doesn’t use energy to move substances down their absorption grade. Active transport process of the plasma membranes processes use energy to move substances across the membrane. Osmosis Lab 2. Explain your observations in detail in terms of concentration gradient, diffusion, osmosis, osmotic pressure, passive transport, and active transport. A. The osmosis lab was a really awesome lab. It gave you the excitement for three days to see how much the egg has changed. Concentration gradient is a ongoing change in the concentration of solutes in a solution as a function of distance through a solution. The concentration gradient of the egg was almost seeing through. You could see the eggs membrane and the yellow oak that was in the center of the egg. Diffusion is the tendency of atoms, molecules, and ions in a liquid or air solution to move from areas of higher concentration to areas of low concentration to become more diffuse. For the diffusion of the egg, the egg expanded and got higher concentration of the water outside of the membrane and a lower concentration inside the osmosis. Osmosis is the movement of water across a selectively permeable membrane into a...
Words: 579 - Pages: 3
...Onion Skin Cell Lab Purpose: To determine the effect of water and saltwater environment on an onion skin cell. Materials: * Eye dropper * Microscope * Onion Skin Cell * Slide * Cover Slip * Iodine * Salt * Water Procedure: Part 1: 1) Attain an onion skin cell sample which has been soaking in tap water from your science teacher. 2) Prepare a wet-mount slide for the onion skin cell directed by your teacher. 3) Add iodine to the onion and place a cover slip on top of the onion. 4) Observe the slide under all magnifications and sketch Proper Biological Diagrams for each power. (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...
Words: 1935 - Pages: 8
...Lab Report on Osmosis and Diffusion Biology 1, Period 3 March 15, 2010 Lab Team: Jason Perez, Kicia Long, Chris McLemore Purpose: The purpose of this lab is to observe the acts of passive transport: diffusion and osmosis in a model membrane system. The experiment will show how molecules in solution move from areas of higher concentration to areas of lower concentration. The model membrane is dialysis tubing. Materials Used 2.5 cm dialysis tubing 15% glucose solution glucose test strip 1% starch solution distilled water Lugol’s iodine solution Procedure: Each member of the lab group will complete the procedures independently 1. Obtain a 30 cm piece of 2.5-cm dialysis tubing that has been soaking in water. Tie off one end of the tubing to form a bag. To open the other end of the bag, rub the end between your fingers until the edges separate. 2. Place 15 mL of the 15% glucose/1% starch solution in the bag. Tie off the other end of the bag, leaving sufficient space for the expansion of the contents in the bag. Record the color of the solution and weight of the bag in a data table. 3. Test the 15% glucose/1% starch solution for the presence of glucose using a test strip. Record the results in the data table. 4. Fill a 250 mL beaker or cup two-thirds full with distilled water. Add approximately 4 mL of Lugol's solution to the distilled water and record the color of the solution in data table. Test this solution...
Words: 750 - Pages: 3
...Laboratory Exercise Osmosis and Diffusion “Osmosis and the Incredible, very Inedible Egg” **This is a fun thing to have your kids or significant other help with. Please note that this experiment takes several days to complete, so don't wait until the last minute to start!** I. Background: Osmosis is the diffusion of water molecules through a semi-permeable membrane. This is how water gets into and out of our cells. In this lab we will investigate the effects of different solutions on the water content of an egg. An egg will serve as our model of a cell. A. Remember, when comparing 2 solutions, the one with the greatest amount of stuff dissolved in it is called hypertonic while the one with the lesser amount of stuff dissolved in it is called hypotonic. Please get these terms straight in your mind before you start the experiment. B. Therefore, hypertonic solutions have less percentage of water in them than hypotonic solutions. Water, like everything else, moves from a greater concentration of itself to a lesser concentration of itself. C. In this experiment you will observe the movement of water into and out of an egg. To do this we will remove the minerals from the egg shell leaving only a membrane that is permeable to water. II. Supplies needed: 3 eggs 4 drinking glasses or clear containers Vinegar (about 2 cups) Foil or plastic wrap White Karo syrup (or any brand like it) Distilled water (actually...
Words: 632 - Pages: 3
...Determining the Osmotic Equilibrium of Potatoes Danielle Soule, Honors Biology, March 18th, 2013 ------------------------------------------------- Abstract: In this lab, our group tried to determine the osmotic equilibrium of potatoes by testing potatoes in solutions of different strengths. We saw that the solutions of lower strengths had swelled the cells of the potatoes and the solutions of higher strengths had decreased the size of the cells of the potatoes. We found that this was due to osmosis. The cells of the lower strength solutions were in a hypotonic solution, and the cells in the higher strength were in a hypertonic solution. We used the information we gathered to conclude the osmotic equilibrium of a potato cell is about 2.7 M. INTRODUCTION Our biology class was learning about the basics of osmosis and diffusion. Diffusion, being the tendency for molecules of any substance to spread out into available space (Cambell 2002), is directly linked to osmosis which is the diffusion of water across a membrane toward the side that cannot transverse the membrane (Johnson, 2000). Thus, in cells, movement of H20 into and out of a cell is influenced by the relative concentration of solute on either side of the cell membrane (Mahar 2013). We saw the affects of osmosis when we submerged potatoes into solutions of different strengths to see how the cells would react to this change in environment. We saw that some of the cells were in a hypertonic solution, which has a...
Words: 1266 - Pages: 6
