Concept explainers
Assume that a membrane permeable to
a.
b.
c. A membrane potential, negative on side 1, would develop.
d. A membrane potential, positive on side 1, would develop.
e. None of the preceding is correct.
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Chapter 3 Solutions
Human Physiology: From Cells to Systems (MindTap Course List)
- Describe the contribution of each of the following to establishing and maintaining membrane potential: (a) the Na+K+ pump, (b) passive movement of K+ across the membrane, (c) passive movement of Na+ across the membrane, and (d) the large intracellular anions.arrow_forwardUsually , rates of diffusion vary inversely with molecular weights; so smaller molecules diffuse faster than do larger ones. In cells, however, calcium ion diffuses more slowly than does cAMP. Propose a possible explanation.arrow_forwardA hypothetical cell has a higher concentration of sodium ions outside the cell than inside the cell but an equal amount of chloride outside the cell and inside the cell. Based on its electrochemical gradient, which direction would chloride ions move across the cell membrane?arrow_forward
- Some antibiotics act as carriers that bind an ion on one side of a membrane, diffuse through the membrane, and release the ion on the other side. The conductance of a lipid-bilayer membrane containing a carrier antibiotic decreased abruptly when the temperature was lowered from 40°C to 36° C. In contrast, there was little change in conductance of the same bilayer membrane when it contained a channel-forming antibiotic. Why?arrow_forwardA red blood cell has an internal salt concentration of ∼150 mM. The cell is placed in a beaker of 500 mM salt. Solve, (a) Assuming the cell membrane is permeable to water but not to ions, describe what will happen to the cell in terms of osmosis. (b) If the membrane were permeable to ions, in which direction would solutes diff use: into or out of the cell?arrow_forwardIn 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. (b) Identify the osmolarity of the apple.arrow_forward
- If you made a hematocrit in two tubes. Tube A is made of 0.60M NaCl, and Tube B is made of 1.00M of NaCl, describe how the cell would respond in these solutions? Which would have a higher rate of osmosis? If the cell is permeable to NaCl, which would have a higher rate of diffusion?arrow_forwardAn osmotic semipermeable membrane that allows only water to pass separates two compartments, A and B. Compartment A contains 0.9% NaCl, and compartment B contains 3% glycerol, C3H8O3. (a) In which compartment will the level of solution rise? (b) Which compartment has the higher osmotic pressure (if either)?arrow_forwardA membrane separates Solution A and Solution B. The membrane has a permeability of 2 x 105 cm/s to urea and has a surface area of 5 cm2. The concentration of urea in Solution A is 2 mg/mL. The initial rate of net diffusion of urea is 1 x 104 mg/s. What is the concentration of urea in Solution B?arrow_forward
- 7. Given the following concentrations: K* ICF 140 mM Na CH 12 mM 12 mM ECF 3 mM 145 mM 120 mM a) Calculate the equilibrium potentials of K, Na* and Cl using the Nernst equation. EK = ENa = ECi = b) In the case above, if the membrane is permeable only to K, what would be the predicted membrane potential? c) If the membrane is equally permeable to K and Na", and impermeable to all other ions, what would be the predicted membrane potential?arrow_forwardA red blood cell with an intracellular fluid (ICF) concentration of 280 mmol/L, is placed into an environment were the concentration of the extracellular fluid (ECF) is 305 mmol/L. As a result, water will move across the cell/plasma membrane. a) Name the process by which water moves b) Describe the overall direction of movement of the water. Answer choices: (i) From outside the cell to inside the cell (ii) From inside the cell to outside the cell, or (iii) Equally, into and out of the cell iii Explain your reasoning for your answer to part (c). 1In your answer you must describe the environment on both sides of the membrane, and use 3 of the following 4 terms correctly; hypertonic, hypotonic, lower solute concentration, higher solute concentrationn (2pts -Correct use of biological terminology, and correct spelling is essential. Edit View Insert Format Tools Table 12pt v Paragraph BIUA ...arrow_forwardIt is typically sufficient to rupture cells when the solute concentration is reduced from 0.15M to 0.001M. Calculate what transmembrane pressure this would result in. Use that to access if the red blood cells would break. Yes or No? Compare to the transmembrane pressure when cells are in normal saline solution (0.91%NaCl) -> 0.156M(change unit to osM) Basically Calculate the transmembrane pressure when the solute concentration is reduced from 0.15M to 0.001M Determine if that transmembrane pressure would result in the breakage of red blood cells Calculate the transmembrane pressure when cells are in a normal saline solution and comparearrow_forward
- Human Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning