Osmosis and Diffusion

In: Science

Submitted By berad2424
Words 1110
Pages 5
Brad Sanford
Bio 1120 Section 6
September 17, 2013
Partners: Dominique & Carleigh
Lab #2: Osmosis & Diffusion

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 sitting inside a beaker filled with water and a potassium iodide solution. The bag is the semipermeable membrane and the cornstarch is our molecule that will diffuse through the membrane and into the potassium iodide solution. The hypothesis of this experiment is the cornstarch will move across the membrane of the plastic bag and into the potassium iodide solution. The starch will turn a…...

Similar Documents

Diffusion and Osmosis

...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......

Words: 2729 - Pages: 11

Ap Biology Diffusion + Osmosis Lab

...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......

Words: 3633 - Pages: 15

Reverse Osmosis

...What is reverse osmosis? What is reverse osmosis? Reverse osmosis is a special kind of diffusion. The word reverse means the opposite of the original direction of movement and osmosis is the movement of water molecules from where they are plentiful to less abundant over a selectively permeable membrane. Therefore, reverse osmosis can be define as when the solvent passes through the selectively permeable membrane from where they are less abundant to where they are in abundance. In other words, reverse osmosis is the flow water molecules opposing the natural direction of osmosis through a porous membrane. The reverse osmosis process happens after the osmosis process. Therefore, in order to fully grasp the process of reverse osmosis one has to understand the process of osmosis first. When a lower concentrated solution and a higher concentrated solution are separated by a selectively permeable membrane, water naturally moves across the membrane to the higher concentrated solution to dilute it. In time, the osmotic pressure will counter the diffusion process precisely and then the solutions will be at equilibrium. No net movement of water will be at this stage. This process is called osmosis. But, if there is an adequate amount of counter pressure applied to the concentrated solution to overpower the osmotic pressure, then osmosis will be reversed. The solution is now coerced through the selectively permeable membrane contrary to the natural flow of water. This is......

Words: 700 - Pages: 3


...atoms that are independent, rapid, and random in motion. These molecules frequently collide with each other and with the sides of the container. In a period of time, this movement results in a uniform distribution of the molecules throughout the system. This process is called diffusion (Everett and Everett, n.d.). Diffusion is defined as the movement of molecules away from the area of their highest concentration to an area of low concentration. Net diffusion can be restated as the movement of particles along the concentration gradient. According to Meyertholen (n.d.), there are several factors which may affect the rate of diffusion of a substance. These factors include the following: (1) Temperature: higher the temp-higher the rate of diffusion, (2) Size of particle: bigger the particle-higher the energy to diffuse , (3) State of matter: solid takes more time to diffuse compared to liquids, liquids take more time to diffuse compared to gases and gases take less time to diffuse compared to liquids and solids, (4) Nature of matter: denser the matter-slower the rate of diffusion. My objective was to determine the properties of ammonia (NH3) and of hydrochloric acid (HCl) that are related to diffusion. I hypothesized that ammonia diffuse faster than hydrochloric acid. For more support we conduct also an experiment that would detect the diffusing substances in an agar plate using colored compounds; potassium permanganate, methylene blue and potassium dichromate...

Words: 268 - Pages: 2

Biology 1020 Diffusion and Osmosis Lab Report

...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...

Words: 873 - Pages: 4


...Introduction Osmosis is a key for every living organism on Earth, from humans to plants. In this lab we examined the processes of osmosis and diffusion. Osmosis is a specialized type of diffusion; “it is the process of water moving across a semi-permeable membrane, in response to a concentration gradient” (Readel, 2000). Fluid passes both in and out of the semi permeable membrane in osmosis, but usually there is a “net flow in one direction or another, depending on which side of the membrane has a higher concentration of solutes” (Smith, 2013). There are different factors that can affect the rate of osmosis such as temperature. In one experiment, my group and I used dialysis tubing to simulate a cell membrane. This tubing was filled with molasses and was immersed in water; cold, warm and hot. The bags were removed at regular intervals and measured for the amount of osmosis that occurred. We observed that the bags in the hot water experienced the highest amount of osmosis. In warmer temperatures the water particles tend to diffuse from high to low concentration, thus trying to dilute the solute concentration from the solution outside. From these observations and conclusion, my group and I hypothesized for our own experiment the level of solute concentration will affect the rate of osmosis. Diffusion is the process of “any substance moving from a region of high concentration to a region of lower concentration” (Readel, 2000). Therefore we predicted that the higher......

Words: 1054 - Pages: 5

Diffusion and Osmosis

...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......

Words: 1249 - Pages: 5

Osmosis Lab

...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......

Words: 2715 - Pages: 11


...lighter molecular weight value diffused at a faster rate. Thus, resulting in the formation of a white smoke in the glass tube moving closer to the side of the heavier substance Hydrochloric Acid (HCl). The agar-water gel set-up consisted of a agar-water gel in a petri dish. Potassium Permanganate (KmnO4), Methylene Blue (C16H18N3SCl) had a drop in each well. Methylene Blue, having the heaviest weight, diffused slowly. Therefore, the heavier the molecular weight, the slower the rate of diffusion. Introduction Many interesting biological facts but usually, when modifications or experiments are tried, the investigator has some reason for doing so. A substance in the gaseous or liquid state consists of molecules or atoms that are independent, rapid, and random in motion. These molecules frequently collide with each other and with the sides of the container. In a period of time, this movement results in a uniform distribution of the molecules throughout the system. This process is called diffusion. Diffusion is a process of equalization which involves movement of molecules from an area of high concentration to an area of low concentration. Materials and Methods Results Methylene Blue(MW: 320g/mole) | Potassium Permanganate(MW : 158g/mole) | Time(min) | Distance (mm) | Rate(mm/min) | Time(min) | Distance (mm) | Rate (mm/min) | 0 | 15 | 0 | 0 | 24 | 0 | 15 | 16 | 1.06 | 15 | 32.67 | 2.178 | 30 | 16.3 | 0.5 | 30 | 36.67 | 1.23 | 45 | 17 | 0.38 | 45 | 40.3 |......

Words: 297 - Pages: 2

Diffusion Lab

...Fatmata Diffusion Abstract dialysis tubing is, made of cellulose because it’s a selectively permeable membrane. In this experiment, we are testing to see if the solution in the beaker moves into the dialysis bag. Which because of that, Introduction Diffusion and osmosis are two types of transport mechanisms. Diffusion is the movement of molecules from areas of higher concentrations to areas of lower concentration until the molecules are evenly distributed through the area. Osmosis is the dispersion of water. Our cells are capable of absorbing nutrients because, the cell membrane is selectively permeable (some molecules can diffuse freely through the membrane while others cannot). In this experiment we used dialysis bag as a model of the cell membrane. Our hypothesis was that the glucose will diffuse out of the membrane into the beaker filled with iodine solution. To demonstrate dialysis tubing we used water, starch and iodine. When starch and iodine react together they form a dark brown color. Materials Rubber band | Dialysis bag | Beaker | Glucose solution | Iodine solution | Water, thread | Methods * Cut a piece of dialysis tubing that has been soaking in water approximately 40 cm (approx. 16 in) long, Tie the end of the dialysis tubing with two or more knots. * Fill the bag halfway with glucose solution. And add 4 full droppers of starch solution to the bag. * Hold the open end close while you mix the content o the bag. Rinse of outside the bag...

Words: 535 - Pages: 3


...Demonstration of Osmosis using visking tubing Aim The aim of the experiment is to demonstrate the effects of osmosis using visking tubing, warm water and sucrose solution. Method Test tube A on the inside is hypertonic because there is a more concentrated solute, on the outside it is hypotonic because there is a less concentrated solute. Test tube B is isotonic both on the inside and outside. Test tube C on the inside is hypertonic and on the outside is hypertonic. Experiment During the experiment 3 test tubes were placed in a wire rack, the test tubes were then labelled A, B and C. Tube A was half filled with 0.1M sucrose solution whilst tube B was half filled with 0.5M sucrose solution, tube C was half filled with 1.0M sucrose solution. Three lengths of visking tubing were soaked in warm water for two minutes. One piece of visking tubing was three quarters filled with 0.5M sucrose solution and knotted at either side, it was then rinsed to get rid of any sucrose solution on the outer tubing. The visking tubing was then dried and weighed. The same was done with test tube B and C. After 10 minutes the cell models (visking tubing) were removed from the test tubes and dried and weighed. The results were recorded and the cell models were returned to the test tubes. After 20 and 30 minutes the same thing was done and results were recorded afterwards. Tube | Start | 10 Minutes | 20 Minutes | 30 Minutes | A | 19.16g | 18.29g | 19.81g | 20.13g | B |......

Words: 499 - Pages: 2


...Osmosis Is Serious Business! by Troy R. Nash Department of Biology Presbyterian College, Clinton, SC Questions-Too Much of a Good Thing 1. The extra fertilizer created a hypertonic environment around the roots of the corn ____/ 2 pts. What sort of environment (hypotonic, hypertonic, isotonic) did the extra fertilizer create around the roots of the corn? 2. The extra fertilizer caused the soil to become hypertonic which cause water to diffuse out of the corn into the soil. This caused the crops to die from lack of water. ____/ 2pts. Keeping in mind your answer to the previous question, what do you believe caused the corn plants to wilt and eventually die? 3. If Michael would have told his dad what he had done, two things could have possibly been done.. One option would have been the removal of as much of the extra fertilizer as possible to reduce the chance of the fertilizer becoming hypertonic. The other option would to be to overwater the crops so the environment would be isotonic and no diffuse would take place because of the equal concentrations of the solutions inside and outside of the plant cells. I think just telling his father would have saved a lot of heartache and trouble. ____/ 2 pts If Michael’s mistake had been caught earlier, is there anything that could have been done to prevent the corn from dying? Questions-Too Little Too Late 1. The distilled water cause the patient’s bloodstream to become a hypotonic environment . ____/2pts. What problem......

Words: 318 - Pages: 2


...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......

Words: 704 - Pages: 3

Osmosis and Diffusion

...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 compartment containing solute that cannot cross the same membrane. The osmosis is what causes the bubbles. Osmotic pressure is the ability of osmosis to generate enough pressure to lift a volume of water. The water equilibrates in the jar. The passive transport exchanges the oxygen 02and C02 in the jar. Active transport of the osmosis lab was against the gradient. Ph.I.L.S Lab 3. Explain what happened to the......

Words: 579 - Pages: 3

Osmosis Problems

...Practice Problems – Osmosis and Water potential Use this key to answer all the problems below. If you choose B or C, rewrite the statement so that it is complete and true. A = TRUE B = FALSE C = NOT ENOUGH INFORMATION PROBLEM ONE: The initial molar concentration of the cytoplasm inside a cell is 2M and the cell is placed in a solution with a concentration of 2.5M. 1. Initially, free energy is greater inside the cell than outside 2. It is possible that this cell is already in equilibrium with its surroundings. 3. Initially, solute concentration is greater outside the cell than inside. 4. Water will enter the cell because solute potential is lower inside the cell than outside. 5. The cell will become flaccid because the pressure potential is greater outside the cell than inside. 6. The cell is already in equilibrium with its surroundings because of the combination of pressure potential and solute potential inside and outside the cell. 7. Initially, the cytoplasm is hypertonic to the surrounding solution. 8. Initially, the numerical value of the solute potential is more negative inside the cell than outside. 9. Net diffusion of water will be from inside the cell to outside the cell. 10. At equilibrium, the molarity of the cytoplasm will have increased. 11. At equilibrium, the pressure potential inside the cell will have increased. PROBLEM TWO: The initial molar concentration of the cytoplasm inside a cell is 1.3 M and the surrounding solution......

Words: 1076 - Pages: 5