B Based on all the charges around a neuronal membrane, the resting membrane potential is closer to that of the potassium ion equilibrium potential than it is to the sodium ion potential. This is because the potassium equilibrium potential is enhanced by the presence of proteins potassium has a stronger charge the electrochemical force of potassium is stronger potassium's concentration gradient is much larger the membrane is more permeable to potassium

B Based on all the charges around a neuronal membrane, the resting membrane potential is closer to that of the potassium ion equilibrium potential than it is to the sodium ion potential. This is because the potassium equilibrium potential is enhanced by the presence of proteins potassium has a stronger charge the electrochemical force of potassium is stronger potassium's concentration gradient is much larger the membrane is more permeable to potassium

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?
Assume that a membrane permeable to Na+ but not to Cl- separates two solutions. The concentration of sodium chloride on side 1 is higher than on side 2. Which of the following ionic movements would occur? a. Na+ would move until its concentration gradient is dissipated (until the concentration of Na+ on side 2 is the same as the concentration of Na+ on side 1). b. Cl- would move down its concentration gradient from side 1 to side 2. 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.
Nervous Tissue electrical and chemical disequilibrium across cell membranes equilibrium potential calculating the equilibrium potential using the Nernst Equation The parameters of the Goldman Equation the reason for a -70mV resting'potential in most excitable cells gated channels particulars Defining depolarization, repolarization and hyperpolarization defining the role for the common ions, (K+, Na+ )special ions Cl, Ca+ have Define Current and ohm's law l=V/R Defining graded potentials and particulars about graded potentials such as subthreshold GP o suprathreshold GP temporal summation spatial summation e1 of 2 418 words English (United States) O Focus B I @ #3 24 & * 3 4 7 8
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).
Which of the following statements best describes the features of voltage-gated K+ channels? They consist of 4 subunits, are activated at the same time as voltage-gated Na+ channels, but do not inactivate. They consist of 4 subunits, are activated by depolarisation and close slowly during the refractory period. They have 24 membrane spanning alpha helices, 4 of which have positively charged amino acids which promote a conformational change in the channel following depolarisation. They consist of 4 subunits and are open at rest which causes the resting membrane potential to be close to the K+ equilibrium potential.
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?
Membrane potential in cells is constantly fluctuating. These fluctuations are called graded potentials and we will learn more about them in future lectures. Look at the fluctuating graded potential in the graph as an example. If Cl- generally has a relatively low membrane permeability, how would increasing Cl- permeability affect this graph?
The membrane potential for an excitable cell membrane is -70 mV, for sodium ions the Nernst equilibrium potential is +50 mV, the conductivity of the single sodium channel is 10 pS. What is the electrochemical potential difference that is the driving force for sodium ions to migrate? How much current flows through an open sodium channel under these conditions?
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+.
True and false - A k+ channel will be just as permeable to Na+ as to K+ because Na+ is a smaller ion - channel proteins are for small things like ions, not larger molecules like sugars - channel proteins have specificity by providing amino acid side chains to H bongs with particular ions in place of those ions binding with water -Ion channels all low ions to pass through in either direction depending on the electrochemical gradient of the ion - the free energy of an ion travelling across the plasma membrane depends completely on the ions concentration inside versus outside the cell
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.
If the equilibrium potential for K* is -90mV, and the charge inside the cell is -70mV, which direction will K move across the membrane assuming there is permeability (membrane leak channels) which allow it to pass?