Lab 2: Osmosis And Diffusion - Mater Lakes
Lab 2: Osmosis and DiffusionPart 1- Diffusion Across a MembraneProblem Statement:Hypothesis: (Think about what you expect to move through the membrane)Materials: Iodine, water, dialysis tubing, 2 beakers, starch solution, graduatedcylinder.Procedures:Variables:Data: Include a data table & observations.
Lab 2: Osmosis and DiffusionPart 1- Diffusion Across a MembraneAnalysis: (Complete the questions below)1. Based on your observations, which substance moved, the iodine or thestarch? Explain.The dialysis bag was permeable to which substance? Explain how you knowthis.Discuss how the bag is a model for the cell. Sketch a diagram of your lab,molecules involved and movement across the cell membrane.Conclusions:
Lab 2: Osmosis and DiffusionSummarize inbullet pointsPart 2- Water Potential in Potato CellsBackground: In animal cells, the movement of water into and out of the cell isinfluenced by the relative concentration of solute on either side of the cellmembrane. If water moves out of the cell, the cell will shrink. If water moves intothe cell, the cell may swell or even burst. In plant cells, the presence of a cellwall prevents the cells from bursting, but pressure does eventually build upinside the cell and affects the process of osmosis. When the pressure inside thecell becomes large enough, no additional water will accumulate in the cell eventhe though cell still has a higher solute concentration than does pure water. Somovement of water through the plant tissue cannot be predicted simply throughknowing the relative solute concentrations on either side of the plant cell wall.Instead, the concept of water potential is used to predict the direction in whichwater will diffuse through living plant tissues. In a general sense, the waterpotential is the tendency of water to diffuse from one area to another under agiven set of parameters. Water potential is expression in bars, a metric unit ofpressure equal to about 1 atmosphere and measured with a barometer. Waterpotential is abbreviated by the Greek letter psiand has two majorcomponents:
Lab 2: Osmosis and DiffusionIn Figure 1.1, a potato cell isplaced in pure water. Initially thewater potential outside the cell is 0and is higher than the waterpotential inside the cell (-3). Underthese conditions there will be a netmovement of water into the cell.The pressure potential inside thecell will increase until the cellreaches a state of equilibrium.
Lab 2: Osmosis and DiffusionProcedures:1. Pour 50 ml of each solution into your measuring cup- Make sure your cups areclean.2. Using the cork boarer, cut out 6 potato cylinders (about the same size), determinethe mass and record .3. Place the cylinders into the beaker one in each of the solutions and cover withplastic wrap. Leave overnight4. Day 2- Remove the cylinders from the beakers and carefully blot of any excesssolution. Record the room temperature in Celsius.5. Determine the mass of the 4 potato cylinder together and record.6. Calculate the % change.Data:Contents in BeakerDistilled Water0.2 M0.4 M0.6 M0.8 M1.0 MInitial MassFinal MassMass difference% Change in Mass
Lab 2: Osmosis and DiffusionAnalysis:1. Graph the results for both your individual data and class average on one graph. Inorder to do so, the 0 axis line should actually be in the middle of your graph. The y axisabove this line should be labeled % increase in mass while the y axis below this lineshould be labeled % decrease. The x axis is the sucrose molarity within the beakers.Contents in BeakerClass AverageDistilled Water0.2 M0.4 M0.6 M0.8 M1.0 M1. Determine the molar concentration of the potato cores. This would be the sucrosemolarity in which the mass of the potato core does not change. To find this, draw thestraight line on your graph that best fits your data. The point at which this line crossesthe x axis represents the molar concentration of sucrose with a water potential that isequal to the potato tissue water potential. At this concentration, there is no net gainor loss of water from the tissue. What is the Molar concentration of the cores?
Lab 2: Osmosis and DiffusionAnalysis:3. Calculate the solute potential for the sucrose solution using the formula. ShowCalculations.4. Explain water potential and describe how it affects osmosis.
Lab 2: Osmosis and DiffusionPart 3- Plasmolysis in Elodea CellsBackground: The cell membrane is a structure that forms the outer boundary of thecell and allows only certain materials to move into and out of the cell. Food, oxygen andwater move into the cell through the membrane. Waste products also leave through themembrane. Cells that perform photosynthesis (plants and some protists) take in carbondioxide through the cell membrane instead of oxygen.Pre-Lab Questions: What is the major function of a cell membrane? Why is the cell membrane sometimes described as a gate? Describe the structure of a cell membrane. How is the structure of the cell membrane related to its function? What is the major function of the cell wall? Describe the structure of the cell wall and its composition. How is the structure of the cell wall related to its function?
Lab 2: Osmosis and DiffusionPart 3- Plasmolysis in Elodea CellsProcedure: Watch the following video- https://www.youtube.com/watch?v OtPaPbVBMbMAnswer the following questions about the videoConclusions: Answer the following questions in your lab notebook.What is the shape of a typical Elodea cell? Draw it. Your drawing should include the cell wall,chloroplasts, and central vacuole. Identify the functions for each structure.What happens to the cells as the salt water flows under the cover slip?What is the shape of the Elodea cell after salt solution has been added? Draw it. . Your drawing shouldinclude the cell wall, chloroplasts, and central vacuoleWhy did the water in the vacuole pass out of the cell?Why didn’t the outer boundary of the cell collapse?
Lab 2: Osmosis and Diffusion Part 3- Plasmolysis in Elodea Cells Background: The cell membrane is a structure that forms the outer boundary of the cell and allows only certain materials to move into and out of the cell. Food, oxygen and water move into the cell through the membrane. Waste products also leave through the membrane.
Lab 4: Diffusion and Osmosis (Revised Fall 2009) Lab 4 - Biol 211 - Page 1 of 23 Lab 4. Diffusion and Osmosis in Selectively Permeable Membranes Prelab Assignment Before coming to lab, read carefully the introduction and the procedures for each part of the experiment, and then answer the prelab q
AP BIOLOGY NAME_ CELL UNIT ACTIVITY #6 DATE_HOUR_ DIFFUSION AND OSMOSIS LAB INTRODUCTION: In this laboratory you will investigate the processes of diffusion and osmosis in a model membrane system. You will also investigate the effect of solute concentration on w
energy –referring to active transport, exocytosis and endocytosis. The correct processes that the molecules Louise was may utiliseinclude A. osmosis, simple diffusion and active transport. B. osmosis and simple diffusion. C. osmosis and exocytosis. D. simple diffusion, exocytosis and endocytosis
Diffusion, Osmosis, and Osmoregulation NOTES January 23, 2012 Passive vs. Active Transport Passive Transport - the movement of molecules, into or out of cells, with the concentration gradient. * No energy required by the cell. * Examples: diffusion and osmosis *Active Transport - the movement of molecules, into or out of cells, against the .
EMA 5001 Physical Properties of Materials Zhe Cheng (2016) 4 Self-Diffusion & Vacancy Diffusion Diffusion of Vacancy vs. Substitutional Atoms Continue from p. 7 2 Therefore, Diffusion coefficient of vacancy vs. substitutional atom For self-diffusion 2 The relationship between jump frequency is Since the jump distance is the same
PRE-LAB ASSESSMENT These questions are designed to help you understand kinetic energy, osmosis, and diffusion and to prepare for your investigations. All lab questions should be answered in thorough, complete sentences. 1) What is kinetic energy, and how does it differ from potential energy? (2 pt) 2) What environmental factors affect .
Select Lab 1: Diffusion & Osmosis Complete the virtual lab activity and record your responses in this packet. Introduction The processes of diffusion and osmosis account for much of the passive movement of molecules at the cellular level. In this laboratory, you will study some of the basic principles of molecular movement in solution and .
Biology Lab Notebook Table of Contents: 1. General Lab Template 2. Lab Report Grading Rubric 3. Sample Lab Report 4. Graphing Lab 5. Personal Experiment 6. Enzymes Lab 7. The Importance of Water 8. Cell Membranes - How Do Small Materials Enter Cells? 9. Osmosis - Elodea Lab 10. Respiration - Yeast Lab 11. Cell Division - Egg Lab 12.
