Calcium is an important regulator of the citric acidcycle. Calcium is transported across themitochondrial inner membrane by a Ca²-2+uniporter that is driven by the negative potentialinside the matrix.Part AAssuming a membrane potential across the inner membrane of 172 mV (inside negative), calculate the ratio of the[Ca2+] in the matrix to that in the cytoplasm ([Ca2+]m/[Ca²+]c) that would exist at equilibrium (i.e., AG = 0).Express your answer using two significant figures.[Ca2+]m[Ca2+]=ΤΟ ΑΣΦSubmitRequest AnswerPart B?Cytoplasmic [Ca2+] is on the order of 10-7 M in a healthy cell. Based on your answer in Part A, calculate the [Ca2+]that would exist in the matrix at equilibrium.Express your answer to two significant figures and include the appropriate units.☐μÅ?ValueUnits

Answered: Calcium is an important regulator of…

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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Calculate the change in Gibbs free energy for transport of Ca2+ from outside to inside the cell. The extracellular Ca2+ concentration is 135 uM, and the intracellular Ca2+ concentration is 98 uM. The membrane potential is -22 mV and the temperature is 37°C. O. -5.1 kJ/mol O 1.2 kJ/mol -410 kJ/mol 3.4 kJ/mol
The Na+ /glucose symport transports glucose from the lumen of the smallintestine into cells lining the lumen. Transport of 1 glucose molecule isdirectly coupled to the transport of 1 Na+ ion into the cell. 1 Na+out + 1 glucoseout → 1 Na+in + 1 glucoseinAssume the following conditions at 37 °C: [Na+]in = 12 mM, [Na+]out =145 mM, [glucose]out = 28 μM, and Δψ = -72 mV (inside negative).(a) What is ΔG for transport of Na+ from outside to inside under theseconditions?(b) What is the upper limit for [glucose]in under these conditions?(c) Which of the two hypothetical symports shown below (A or B) wouldachieve the highest concentration of [glucose]in under the conditionsdescribed above? Briefly explain your choice. A: 1 Na+out + 2 glucoseout → 1 Na+in + 2 glucosein B: 2 Na+out + 1 glucoseout → 2 Na+in + 1 glucosein
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)
What is the energy requirement to transport 3 mol of Na+ across the membrane by the Nat-K+ ATPase transporter protein at 37 °C under conditions in which the membrane potential is 70 mV (the inside of the cell is negative relative to the outside) and the ion concentrations are as follows: + [K*]outside = 5 mM [K+Jinside = 140 mM [Na]outside = 150 mM [Na]inside = 10 mM O-41.22 kJ + 13.74 kJ +41.22 kJ O-13.74 kJ
Intracellular concentrations in resting muscle are as follows: fructose6-phosphate, 1.0 mM; fructose-1,6-bisphosphate, 10 mM; AMP, 0.1 mM;ADP, 0.5 mM; ATP, 5 mM; and Pi, 10 mM. Is the phosphofructokinasereaction in muscle more or less exergonic than under standard conditions?By how much?
Intestinal epithelial cells pump glucose into the cell against its concentration gradient using the Na+– glucose symporter. Recall that the Na+ concentration is significantly higher outside the cell than inside the cell. The symporter couples the "downhill" transport of two Na+ ions into the cell to the "uphill" transport of glucose into the cell. If the Na+ concentration outside the cell ([Na+]out) is 163 mM and that inside the cell ([Na+]in) is 21.0 mM, and the cell potential is −54.0 mV (inside negative), calculate the maximum energy available for pumping a mole of glucose into the cell. Assume the temperature is 37 °C.
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.
What is the energy requirement to transport 2 mol of K* across the membrane by the Nat-K+ ATPase transporter protein at 37 °C under conditions in which the membrane potential is 70 mV (the inside of the cell is negative relative to the outside) and the ion concentrations are as follows: [K+]outside = 5 mM [K+Jinside = 140 mM [Na loutside = 150 mM [Na+Jinside = 10 mM +1.83 kJ + 3.66 kJ O-1.83 kJ O-3.66 kJ
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?
Intestinal epithelial cells pump glucose into the cell against its concentration gradient using the Na-glucose symporter. Recall that the Na* concentration is significantly higher outside the cell than inside the cell. The symporter couples the "downhill" transport of two Na* ions into the cell to the "uphill" transport of glucose into the cell. If the Nat concentration outside the cell ([Na lout) is 141 mM and that inside the cell ([Na* lin) is 19.0 mM, and the cell potential is -52.0 mV (inside negative), calculate the maximum energy available for pumping a mole of glucose into the cell. Assume the temperature is 37 °C. AGglac 9.63 Incorrect kJ mol What is the maximum ratio of [glucose), to [glucose)out that could theoretically be produced if the energy coupling were 100% efficient? O 2700 1.13 3.7 x 10- 7.90
Intestinal epithelial cells pump glucose into the cell against its concentration gradient using the Na*-glucose symporter. Recall that the Na+ concentration is significantly higher outside the cell than inside the cell. The symporter couples the "downhill" transport of two Na+ ions into the cell to the "uphill" transport of glucose into the cell. If the Na+ concentration outside the cell ([Na* lout) is 147 mM and that inside the cell ([Na+]in) is 17.0 mM, and the cell potential is -54.0 mV (inside negative), calculate the maximum energy available for pumping a mole of glucose into the cell. Assume the temperature is 37 °C. AG gluc kJ mol What is the maximum ratio of [glucose]in to [glucose] out that could theoretically be produced if the energy coupling were 100% efficient? 1.13 2.3 × 10-4 8.36 4300
In considering active transport by Na + -K + -ATPase at body temperature (37 o C), 3 Na+ are pumped out of the cell and 2 K + are pumped in for each ATP that is hydrolyzed to ADP + P i . Given that underyour experimental conditions, the DG for ATP hydrolysis is -10 kcal/mol, and that V is -60 mV, and that the pump maintains the internal Na + at 10mM, external Na + at 120 mM, internal K + at 120 mM and external K + at 8mM, what is the efficiency of the pump (i.e., what fraction of the energy available from ATP hydrolysis is required to drive transport at the provided levels)?

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