1. (a) In class thus far, we have focused our membrane transport energetics discussions on the transfer of K+ ions. Of course, in the cell there are other ions that contribute to the overall resting membrane potential (Autotal). To estimate the overall resting membrane potential for the predominant ions present in the cell, we must first calculate the individual resting membrane potential. Using the Nernst equation discussed in class, and the values provided below, calculate A for each ion. lon K+ Na+ Ca²+ CI- outside cell 6 mM 145 mM 4 mM 90 mM [ion] [ion] inside cell 145mM 8 mM 0.001 mM 6 mM

1. (a) In class thus far, we have focused our membrane transport energetics discussions on the transfer of K+ ions. Of course, in the cell there are other ions that contribute to the overall resting membrane potential (Autotal). To estimate the overall resting membrane potential for the predominant ions present in the cell, we must first calculate the individual resting membrane potential. Using the Nernst equation discussed in class, and the values provided below, calculate A for each ion. lon K+ Na+ Ca²+ CI- outside cell 6 mM 145 mM 4 mM 90 mM [ion] [ion] inside cell 145mM 8 mM 0.001 mM 6 mM

Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter3: The Plasma Membrane And Membrane Potential

Section: Chapter Questions

Problem 2SQE: One of the important uses of the Nernst equation is in describing the flow of ions across plasma...

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One of the important uses of the Nernst equation is in describing the flow of ions across plasma membranes. Ions move under the influence of two forces: the concentration gradient (given in electrical units by the Nernst equation) and the electrical gradient (given by the membrane voltage). This is summarized by Ohms law: Ix=Gx(VmEx) which describes the movement of ion x across the membrane. I is the current in amperes (A); G is the conductance, a measure of the permeability of x, in Siemens (S), which is I/V;Vm is the membrane voltage; and Ex is the equilibrium potential of ion x. Not only does this equation tell how large the current is, but it also tells what direction the current is flowing. By convention, a negative value of the current represents either a positive ion entering the cell or a negative ion leaving the cell. The opposite is true of a positive value of the current. a. Using the following information, calculate the magnitude of Na [ Na+ ]0=145mM,[ Na+ ]i=15mM,Gna+=1nS,Vm=70mV b. Is Na+ entering or leaving the cell? c. Is Na+ moving with or against the concentration gradient? Is it moving with or against the electrical gradient?
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.
Calculate the equilibrium membrane potentials to be expected across a membrane at 37 ∘C, with a NaCl concentration of 0.50M on the "right side" and 0.08 M on the "left side", given the following conditions. In each case, state which side is (+) and which is (−). (a)Membrane permeable only to Na+.
Calculate the equilibrium membrane potentials to be expected across a membrane at 37 ∘C, with a NaCl concentration of 0.50 M on the "right side" and 0.08 M on the "left side", given the following conditions. In each case, state which side is (+) and which is (−). Membrane equally permeable to both ions.
The ion flows across neuronal membranes at rest and duringan action potential do not significantly change bulk ionconcentrations, except for that of Ca2+ ions. Resting Ca2+ ionconcentrations in cells are usually about 10–7 M, and Ca2+ ionsexert physiological effects at concentrations of perhaps 10–5 M.Explain why relative changes of intracellular [Ca2+] are muchgreater than for, say, [Na+] (12–50 mM).
Calculate the equilibrium membrane potentials to be expected across a membrane at 37 °C, with a NaCl concentration of 0.10 M on the “right side” and 0.01 M on the “left side”, given the following conditions. In each case, state which side is (+) and which is (-). (a) Membrane permeable only to Na+ (b) Membrane permeable only to Cl– (c) Membrane equally permeable to both ions
Separately, draw a table using arrows to depict the appropriate magnitude and direction of the forces and ion fluxes at different membrane potentials for a ligand-gated channel that is equally permeable to both ion X+ and ion Y+. The equilibrium potential for ion X+ is -60 mV, and the equilibrium potential for ion Y+ is -20 mV. Which item best represents the forces and fluxes for a membrane potential of 0 mV?
What is the equilibrium membrane potential due to Na+ ions if the extracellular concentration of Na+ ions is 154 mM and the intracellular concentration of Na+ ions is 27 mM at 20 ∘C ? Please answer asap and in short and content should not be palgarised please
What happens across the membrane of an electricallyactive cell is a dynamic process that is hard to visualizewith static images or through text descriptions. View thisanimation (http://openstaxcollege.org/l/dynamic1) toreally understand the process. What is the differencebetween the driving force for Na+ and K+? And what issimilar about the movement of these two ions?
Calculate the maximum ratio that can be achieved by the plasma membrane Na+-glucose symporter of an epithelial cell when [Na+]in is 12 mM, [Na+]out is 145 mM, the membrane potential is −50 mV (inside negative), and the temperature is 37 °C.
How can the resting membrane potential of a membrane be calculated using the Goldman-Hodgkin-Katz (GHK) equation?
The extracellular concentration of Cl-Cl¯ is 123 mM and the intracellular concentration is 4 mM. In which direction does Cl-CI¯| flow through an open channel when the membrane potential is in the -60 mV-60 mV to +30 mV+30 mV range?