8. Phosphate buffered saline (PBS) is often used as an isotonic solution to keep cells happy and alive. Though recipes vary, PBStypically contains 157 mM Na* and 4.5 mM K+, yet inside of the cell that ratio is switched (there is approximately 150 mM K*and only about 10 mM Nat). Why is PBS still considered isotonic? That is, why does putting cells into PBS not create a lot ofosmotic pressure?

Osmosis is the movement of water across the semipermeable membrane driven by the difference in…

Answered: 8. Phosphate buffered saline (PBS) is…

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter5: Membranes And Transport

Section: Chapter Questions

Problem 8TYK

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7. Imagine that the red blood cells shown below are suspended in liquids of 3 different concentrations. a. Identify the solution in each box as either hypertonic, hypotonic, or isotonic. b. Describe the reasons for your choice of tonicity. Solution 1 2 3 Red Blood Cells Top-Down View Side View Tonicity of Solution? Reasoning?
4. A researcher is interested in the mode of transport of three different substances (A, B, & C) across the cell membrane. The researcher's data is presented in the graphs below. A) A Initial rate of transport into the Bor C cell Concentration The graph above shows the initial rate of transport for each substance when cells that do not contain A, B, or C are placed in solutions of differing concentrations of A, B, and C, respectively. Based on this data, which of the following is/are compatible modes of transport for substance A? (active transport, facilitated diffusion, simple diffusion) For substance B? For substance C?
Osmosis Practice Activity Osmosis is the diffusion of water from an area of high concentration to an area of low concentration. Only water moves in osmosis! The diagrams below show the concentration of water and salt inside the cell and the concentration of water and salt surrounding the cell. Complete the sentences below by comparing the concentration of the water inside the cell and the concentration outside the cell. 1. a. Water will flow the cell, out of the cell, in both directions). (into 5% NaCl 95% H20 95% NaCI 5% H20 b. The cell will (shrink, burst, stay the same). a. Water will flow (into the cell. 2. 5% NaCl out of the cell, in both directions). 5% NaCl 95% H20 95% H20 b. The cell will (shrink, burst, stay the same).
2. (a) Define concentration polarization and polarization modulus. How is polarization modulus mathematically related to filtration flux? (b) If bacterial cell debris has G t = 54 x 106 sec, what centrifuge speed is needed to effect a full sedimentation in two hours? (centrifuge having bowl diameter of 10 cm)
6. A carrot, when dried out, becomes soft. There is a way to make it firm and crisp. Explain how and why, using the following guidelines. a) Draw and label a representative cell of the carrot, in its dried state. Be precise in your drawing. b)Describe the type of extracellular solution that is appropriate to add to make the desired change (name and define what type of solution, the net movements of solvent and solutes, etc.). c)Draw a representative cell of the carrot, in its possible state after the change. Represent the movement of water using an arrow to indicate what has happened.
8.Patients who enter the emergency room dehydrated are usually given sterile saline solution intravenously. The solution administered is isotonic to prevent cell damage. What would happen if the solution was hypotonic? Group of answer choices A. Hypotonic solutions have a higher osmotic pressure than that within cells so hemolysis can occur B. Hypotonic solutions have a lower osmotic pressure than that within cells so crenation can occur can occur. C. Hypotonic solutions have a lower osmotic pressure than that within cells so hemolysis can occur. D. Hypotonic solutions have the same osmotic pressure as that within cells so nothing will happen. 9.The solubility of CaCl2 in water is135g/100 ml. What would be the best method for preparing a 50.0 mL of supersaturated CaCl2 solution? Group of answer choices A. add 72 g of CaCl2 to 50.0 mL of H2O at 100 °C while stirring at room temperature B. add 67 g of CaCl2 to 50.0 mL of H2O at 100 °C while stirring at room temperature…
7. The diffusion constant for the membrane protein fibronectin is approximately 0.7 x 10-12 cm²/sec, whereas that for rhodopsin is about 3 x 10-9 cm2/sec. Calculate the distance traversed (in nanometers) by each of these proteins in 50 msec.
2. 1. Compare and contrast between passive transport, active transport and bulk transport? Explain (using the correct terminology and drawing an image) what happens to the cells in the following environments: a. A human blood cell (0.9% salt) is placed in a salt water tank (27.5% salt). b. A bacterial cell with 35% organic material in their cytoplasm is living in a tank filled with 35% sulfur. c. A freshwater plant cell (75% water) is living in a pond that floods over. 3. List and briefly define the two Laws of Thermodynamics (energy).
1. Using the data provided in Table 1, construct a graphical representation of the data to visualize the differences of the diffusion rates of Congo red and Toluidine blue in the three agar concentrations and between different temperatures. Table 1. Diffusion rates of Congo red and Toluidine blue in the three agar concentrations under different temperatures Agar (%) 3 cr crc w 3 5 5 7 7 Room temperature: 26% Refrigerator: 15% Temperature Room Refrigerator Room Refrigerator Room Refrigerator Diffusion Rates (mm) Congo Red 10 11 17 14 20 18 Toluidine Blue 7 7 14 7 16 9
In an investigation of osmosis, apple cores were submerged in different molarity solutions to determine the unknown osmolarity of the apple. To determine the molarity five uniform apple cores were massed before submerging them in different molarity solutions. After 24 hours the apple cores were massed again. Then the percent change in mass was determined for the five uniform apple cores in each molarity solution. c) Describe the environmental conditions taking place in each of the six solutions with the apples
9. Using the images of blood from 7.8 in the lab manual, what is the ideal tonicity of sheep's blood? Explain. 10. Using the image in 7.9 of the Elodea cell tissue in the lab manual, why is a hypertonic environment dangerous to plant cells? Explain. 11. Review the following experiment and answer the questions. You set up an experiment where you place a sealed (clamped) dialysis tube cell in a beaker of water. The solution in the dialysis tube cell is 25%NaCl solution and the solution in the beaker is 1%NaCl solution. The solvent for both is water. Before you place the tube in the cell, after it has been filled and clamped, you find the mass of the cell. You also find the mass of the cell after it has been placed in the beaker solution for 30 minutes. The masses are in the table below. Mass in grams of dialysis tube cell Initial Mass 25g Final Mass after 30 minutes 28.7g Using this information, explain the difference in mass before and after submerging the cell in the beaker solution.…
6. Which diagram shows the appearance of a cell with an original Y of -1.2 kPa, after being placed in a solution as shown? A B C D water potential (Y) of external solution / kPa -06 -1-2 -00 -1-5 7. Which pair of factors is inversely proportional to the rate of diffusion? A. Concentration gradient and surface area over which diffusion occurs. B. Distance over which diffusion occurs and size of diffusion molecule. C. Size of diffusion molecule and concentration gradient. D. Surface area over which diffusion occurs and distance over which diffusion occurs. 8. The diagram shows two molecules of glucose. Four possible bonding positions are labelled p, q, r and s; and t, u, v and w. CH,OH CH,OH ОН OH Но ОН Но OH S w u OH OH V When these two molecules condense to form glycogen, where could bonds form? A. p-u or p – v B. p- u or q - w C. p – v or q – w D. p – w or v - w

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