4. Cells have an intracellular [Ca²+] = 0.1 µM. If cells hydrolyzed 1 mol of ATP understandard conditions (AGO ATP hydrolysis = -30.5 kJ/mol) for active transport, what is thetheoretical [Ca²+] outside of the cell against which this would not be enough energyto pump any additional Ca²+ ions? Assume the transmembrane potential is 50 mV,temp = 298 K, R = 0.008315 kJ/mol, and F = 96.5 kJ/V*mol.www.

Gibbs free energy change for the ion to move across the membrane (both chemical and electrical…

Answered: Cells have an intracellular [Ca²+] =…

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

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In the situations described below, what is the free energy change if 1 mole of Na* is transported across a membrane from a region where the concentra- tion is 1 µM to a region where it is 100 mM? (Assume T = 37 °C.) (a) In the absence of a membrane potential. (b) When the transport is opposed by a membrane potential of 70 mV. (c) In cach case, will hydrolysis of 1 mole of ATP suffice to drive the trans- port of 1 mole of ion, assuming pH 7.4 and the following cytoplamic concentrations: ATP= 4.60 mM, P = 5.10 mM, ADP = 310 µM?
Suppose that the concentration of CI outside the cell is 100 and inside the cell is 10 mmol/liter. The Nernst equation at 20°C is: Eton = 58 millivolts/z- [10810 (m)] [lonlin You set the membrane voltage at 0 millivolts using a voltage clamp, and measure membrane current. If Cl is the only ion crossing the membrane, you would expect to see: Onegative charges flowing into the cell negative charges flow out of the cell 0 current the membrane hyperpolarizes (becomes more negative)
In the situations described below, what is the free energy change if 1 mole of Na+ is transported across a membrane from a region where the concentration is 48 μM to a region where it is 110 mM? (Assume T=37∘C.) When the transport is opposed by a membrane potential of 70 mV.
Calculate the energy cost (free-energy change) of pumping Ca2+ from thecytosol, where its concentration is about 1.0 × 10−7 M, to the extracellularfluid, where its concentration is about 1.0 mM. Assume a temperature of 37°C (body temperature in a mammal) and a standard transmembrane potentialof 50 mV (inside negative) for the plasma membrane.
Uniporters and ion channels support facilitated transport across cellular membranes. Although both are examples of facilitated transport, the rates of ion movement via an ion channel are roughly 104 - to 105 -fold faster than the rates of molecule movement via a uniporter. What key mechanisticdifference results in this large difference in transport rate?What contribution to free energy (ΔG) determines the direction of transport?
In the following situations, what is the free energy change if 1 mole of Na+is transported across a membrane from a region where the concentration is1 μM to a region where it is 100 mM?(Assume T = 37 °C.) (a) In the absence of a membrane potential. (b) When the transport is opposed by a membrane potential of 70 mV. (c) In each case, will hydrolysis of 1 mole of ATP suffice to drive the transport of 1 mole of ion, assuming pH 7.4 and the following cytoplasmic concentrations: ATP = 4.60 mM, Pi = 5.10 mM, ADP = 310 μM?
You are considering transport of Fe3+ out of a biological cell with a membrane potential of -60 mV. What is the value for delta psi in this case? (Make sure you express this value in proper units, i.e., as you would enter this value into the change in free energy of transport equation.)
Uniporters and ion channels support facilitated transport across cellular membranes. Although both are examples of facilitated transport, the rates of ion movement via an ion channel are roughly 104- to 105-fold faster than the rates of molecule movement via a uniporter. What key mechanistic difference results in this large difference in transport rate? What contribution to free energy (ΔG) determines the direction of transport?
The sarcoplasmic reticulum Ca2+-ATPase, pumps 2 mol Ca2+ out of sarcomeres per mol ATP hydrolyzed. Given the following steady-state concentrations and a membrane potential of 67 mV (inside negative), calculate ΔG for the following active transport process at 37 ∘C and pH=7.4:2Ca2+(in)+ATP+H2O→2Ca2+(out)+ADP+Pi+H+
The average time it takes for a molecule to diffuse adistance of x cm is given byt = x2/2D where t is the time in seconds and D is the diffusioncoefficient. Given that the diffusion coefficient ofglucose is 5.7 × 10−7cm2/s, calculate the time it wouldtake for a glucose molecule to diffuse 10 μm, which isroughly the size of a cell.
For a typical vertebrate cell with a membrane potential of −0.070 V (inside negative), what is the free-energy change for transporting 1 mol of Na+ from the cell into the blood at 37 °C? Assume the concentration of Na+ insidethe cell is 12 mM and in blood plasma it is 145 mM.
The sarcoplasmic reticulum Ca2+-ATPase, pumps 2 mol Ca2+ out of sarcomeres per mol ATP hydrolyzed. Part A: Given the following steady-state concentrations and a membrane potential of 64 mV (inside negative), calculate ΔG for the following active transport process at 37 ∘C and pH=7.4: 2Ca2+(in)+ATP+H2O→2Ca2+(out)+ADP+Pi+H+ ATP=2.8mM,ADP=206μM,Pi=5.4mM,Ca2+(in)=34μM,Ca2+(out)=2.2mM The answer to part A was -7.4 kJ/mol I need help with Part B: Part B: The activity of the Ca2+-ATPase is regulated reversibly under normal conditions to maintain homeostatic concentrations of Ca2+ inside the sarcomere. However, in a rare genetic disorder, irreversible activation of the Ca2+-ATPase can occur. Assuming 37 ∘C, pH=7.4, and the steady-state concentrations for ATP, ADP Pi, and Ca2+(out) given in part (a) calculate the minimum [Ca2+] inside a sarcomere that has irreversibly activated Ca2+-ATPase (i.e., the Ca2+-ATPase activity is always “on”).

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