...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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...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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...Abstract: The rate of osmosis was examined through an experiment. Dialysis tubes were used to simulate a cell membrane. Solutions of 0.20 % and 0.40% sucrose were placed in each tube. The bags were placed into water and let to sit for three intervals of fifteen minutes. In the first bag that had no sugar solution, it had an osmosis rate of -.04 g/min. In the second bag that had 20 percent sugar solution, it had an osmosis rate of .09 g/min and the bag that had 40 percent of sugar solution had an osmosis rate of .11 g/min. What was concluded from the results is that the more percent of sucrose solution, the higher the rate of osmosis will occur and the lower the percentage of sucrose solution, the lower the rate of osmosis. Introduction: In order to understand the process of osmosis, proper terms must be defined. The first term was osmosis itself, osmosis is defined as the passive transport that refers to the diffusion of water across a selectively permeable membrane (Reece, 2009). Then of course, there are three different cases of osmosis which were defined. Hypertonic is a solution with a higher solute concentration. Hypotonic is a solution with a lower solute concentration. Isotonic is when the cells solute concentration is equal. The volumes were all made possible to increase or decrease via the plasma membrane, the plasma membrane defined as a flexible boundary between the living cell and its surrounding (Reece,2009) The dialysis tube represents the plasma membrane and...
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...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...
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...Atichai Suwannapeng Pre Lab #6 Diffusion, Osmosis, and Tonicity Group #3 Section A3 Group Members: Laghu Shakya, Alex Maican, Kelvin Chen, Ziye Lin 10/18/2015 Abstract: In this lab we will be gaining an understanding of how transport in membranes work. This is important because in our semi permeable cell membrane the mode of movement relies on transport. Some methods of transportation for molecules are simple diffusion, facilitated diffusion, active transport, exocytosis and osmosis. The reason molecules tend to move around when dissolved in a solution is because all molecules display random thermal motion and have kinetic energy. Kinetic energy is what allows the molecules to diffuse down a gradient of high concentration to regions of low concentration until the distribution of molecules become equal and achieved dynamic equilibrium. The entire solution only becomes homogeneous when one of the several factors are reached: the size of the dye molecules, temperature of the solution, density of the solvent and concentration of the dye. Heat is what causes random motion of molecules and passively moves molecules in biological systems. However, we can’t see this movement with our naked eye. In order for us to see this movement, we must use a microscope to see the small particles move after collision, this is called the Brownian movement. When talking about the cell membrane we must understand that it is selectively permeable, which means it can choose what can pass through...
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...Osmosis Experiment Diana Arrowood Grand Canyon University BIO-100L Biology Concepts September 16, 2011 Osmosis Experiment Directions Use the information below to complete the Osmosis Experiment. Materials 1 fresh baking potato Water Salt Four small containers (i.e., drinking cups or clear glasses) A metric ruler Methods and Procedure 1) Place 1 cup (236 ml) of water in each of the 4 containers. In 2 of the containers, add 1 tablespoon (14.8 ml) of table salt and mix well until dissolved. Label which containers have salt. Cut a fresh baking potato into 5 mm slices. Cut four rectangles 2.5 cm x 1 cm from the slices as close to the same size as possible. Measure the length and width of each rectangle in metric units and place one in each of the containers, keeping track of which measured slice went in which container. There will be two slices (duplicates) for fresh water and two for salt water. After 1 hour, remove and measure the length and width of each piece of potato and return it to the appropriate container. Note any physical changes. After 24 hours, remove and measure the length and width of each piece of potato. Note any physical changes in the potatoes and describe their appearance. Written Lab Report Introduction 1) Address the following questions: A) Define osmosis. Osmosis is the movement of solvent molecules through a selectively permeable membrane into a region of higher solute concentration, aiming to equalize the solute concentrations...
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...The aim of this experiment is to investigate the influence of various alcohols and temperature on the permeability of beetroot cell membrane. The different types of alcohol will include ethanol, methanol, propanol, butanol and the tissue from the beetroot will be exposed different salt concentrations (0%, 5% ,10% and 20%) . The stress affecting the membrane’s permeability will be assessed by the amount of leakage of pigment caused. ‘Homeostasis the ability of the body or a cell to seek and maintain a condition of equilibrium or stability within its internal environment when dealing with external changes’ (Biology, 2014). Organelle membranes and the plasma membrane are selectively permeable, allowing water to pass through freely, but regulating the movement of solutes. The function of a cell membrane is to transport and allow certain substances into the cell, while keeping other substances out. Surrounding the cytoplasm of a cell, the cell membrane (plasma membrane) is a thin semi-permeable membrane (Bailey, 2014) consisting mostly of lipids and proteins and composed up of a phospholipid bilayer. This contributes to the selectively permeable nature of the membrane. 70% of proteins contribute to the cell membrane, allowing communication outside and inside the cell. The phospholipids arrange themselves so that hydrophobic tails are shielded from the surrounding water exposing the hydrophilic heads to the water. While small molecules and non-charged ions cross freely, big charged...
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...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...
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...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...
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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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...Clara Skepple Miranda Wilby, Sarah Cavanagh Thursday, March 3 2016 Observing Diffusion and Osmosis INTRODUCTION: Related Theory: The cell membrane is the outermost boundary of the cell, made up of proteins and lipids. This membrane holds the cell together and establishes the movement of materials that go into and out of the cell. This is a selectively permeable membrane: a barrier that allows some molecules to pass through, but prevents other molecules from penetrating (1). Passive transport is the movement of materials across a cell membrane without the use of energy from the cell. One type of passive transport is diffusion. Diffusion involves the movement of molecules from an area with a higher concentration to one with a lower concentration (1). Diffusion is affected by many things; temperature, concentration and pressure. It disperses until molecules are equally distributed within a space. Osmosis is diffusion of water through a selectively permeable membrane. Water will diffuse from the place with higher concentration to the place with a lower concentration. Water goes through the concentration gradient. Which is when molecules without energy diffuse from the place with higher concentration to the one with lower (1). The ability to diffuse through water all depends on the size of the molecule as well. For example, starch is a large molecule therefor it should not fit through the cells membrane. Starch is a polysaccharide because it is comprised of lots of sugars. Individually...
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...Change in Potato Cells Due to the Effects of Osmosis (AYE YO POTATO! HOW MUCH OSMOLARITY YOU GOT?) Introduction: The purpose of this experiment was to determine the osmolarity of a potato. Osmolarity is defined as the solute concentration expressed as molarity. Lerner and Lerner (2008) define osmosis as the movement of water across a membrane that is selectively permeable. Osmosis is important in plant cells because it plays a role in regulating guard cells, which are cells that are on the surface of a plant’s leaves and control the opening of the stoma. When the stoma is open, it increases the water movement out of the plant by a process called transpiration. When there is a shortage of water, the guard cells well get smaller and close the stomata, and the transpiration process will move slower. The osmolarity would be tested with solute concentrations ranging from 0.0 M to 0.6 M. The concentrations increased 0.1 M each time and the solute used was sucrose. The goal of this experiment was to determine which concentration had the least effect on the potato after being incubated. This information helped us estimate the osmolarity of the potato tuber tissue. Our group hypothesis is that the osmolarity of the potato will have the concentration with the 0.1 M solution. This hypothesis is based off the predicted outcome that smaller molarity concentrations will have the least effect on the potato. The more solute added to a solution decreases the concentration of water in most cases (Kosinski)...
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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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...cells in support of the higher demand of oxygen. The muscle cells extract energy from the protein and other valuable nutrients to generate ENERGY. This process is referred to as ATP. “Tonicity is how a cell loses or gains water from its surrounding solution. From here cells maintain the mass balance through a process called diffusion, all this means is the ability to spread out evenly in an available area. Isotonic simply means the ability to replace air, water, energy at the rate it is losing it. Hypotonic is a solution with a solute concentration less than the cell. Hypertonic is the opposite a solution with a higher solute concentration. Osmosis, the diffusion of water across a membrane. Membranes exhibit selective permeability; that is, they allow some substances to cross more easily than others. Campbell Biology: Concepts & Connections, Seventh Edition, by Jane B. Reece, Martha R. Taylor, Eric J. Simon, and Jean L. Dickey. Published by Benjamin Cummings. 2012 by Pearson Education,...
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...Cell Membrane Transport Harjot Dhesi Zoology 2011-13 Amon Gekombe 17 February 2014 Introduction The human body must maintain a balance within itself in order to abstain from disturbances caused by the external environment, for example a sudden increase in the outside temperature, or even the internal environment of the body, such as a dramatic drop in blood pressure. The body maintains this equilibrium through various methods and regulators, beginning in the cellular level. The human cell has a selectively permeable plasma membrane, allowing only certain substances to easily pass through to reach the inside or outside of the cell. Small, uncharged, and nonpolar molecules pass with the most ease through the plasma membrane (Tortora and Derrickson 2012). The constant moving in and out of substances is crucial in sustaining the life of the cell. Tortora and Derrickson explain in their book Principles of Anatomy and Physiology that, “Certain substances must move into the cell to support metabolic reactions. Other substances that have been produced by the cell for export or as cellular waste products must move out of the cell” (Tortora Derrickson 2012). Because of the selectively permeable nature of its plasma membrane, the cell can retain chemicals that have a difference in concentration on the inside than on outside of the cell. This is called the concentration gradient. A substance can either move against its concentration gradient by an active process, which requires...
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