Compute the free energy change in Joules thatoccurs at 303 K as the cell is tranitions from restingstate to the maximum depolarization potential.●At resting state, the intracellular potassium andsodium concentrations are 140 mM and 10 mm,respectively. The extracellular sodium and potassiumconcentrations are 145 mM and 5 mM respectively.

For free energy calculation, we can use the Nernst free energy equationi.e ΔG = -nF.ΔEWhere, ΔG =…

Answered: Compute the free energy change in…

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

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter4: Principles Of Neural And Hormonal Communication

Section: Chapter Questions

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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?
Calculate the free energy of transport for the movement of potassium by the sodium/potassium pump under normal physiological conditions: 4 mM serum potassium, 135 mM intracellular potassium, 37.1 °C, and resting potential -82 mV. Express your answer in kJ/mol. Show all work. Calculate the free energy of transport for the movement of potassium by the sodium/potassium pump under disturbed conditions of 2 mM serum potassium. Assume all other parameters remain the same. Express your answer in kJ/mol. Show all work. What factors could limit the continued action of the sodium/potassium pump when only 2 mM potassium is present in the blood plasma? Note that under normal physiological conditions, the cell interior contains 11 mM sodium and the blood contains 140 mM sodium.
Table Q1(a) shows typical values for the intracellular and extracellular concentrations of the major ion species (in millimoles per litre) for frog skeletal muscle. Table Q1(a) Permeability (cm/s) 2 x 10-8 2х 10 Ions Intracellular Extracellular Na* 12 145 K+ 155 4 4 120 4 x 106 By referring to Table Q1(a), compute the equilibrium resting potential for this membrane by assuming the room temperature is 20° C. Given the Boltzman's constant, k = 1.38 x 1023 J/K and an electronic charge, q = 1.602 x 10-19 C.
Define electrochemical gradients and the term “polarized”, and describe the electrochemical basis of the resting membrane potential including the function of the sodium-potassium pump in maintaining the resting membrane potential.
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).
Given that the extracellular concentration of Cl- is approximately 120 mM, what is the intracellular concentration if the Nernst potential for Cl- is 39 mV. (T=298 K, R=1.987 cal/K·mol, F=23,062 cal/mol·V)
At the peak of the action potential, Vm is approximately -65 mV. Assuming normal intracellular and extracellular K+ concentrations (refer to the table), (1) calculate the driving force (in mV) that acts on K+ ions and (2) use the information obtained in part 1 to determine the direction in which K+ ions will flow (i.e., into the cell or out of cell)
Nernst (equilibrium) Potential (mV) - 6.lol 0.07 0.125 D.094 lon Intracellular Extracellular Concentration (mM) Concentration (mM) K* 155 4 Nat 12 145 Ca** 104 1.5 4 120 D) If during the generation of an action potential in the skeletal muscle cell the membrane potential approaches +65 mV, membrane permeability for which ion likely plays a major role in membrane depolarization? Explain your choice.
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 driving force for Na+, K+, and Ca2+ current in a neuron under physiological conditions.
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.
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

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