3. Living cells "pump" singly ionized sodium ions, Na+, from the inside of the cell to the outside across the membrane potential AVmembrane Vin - Vout= -70 mV. It is called pumping because work must be done to move a positive ion from the negative inside of the cell to the positive outside, and it must go on continuously because sodium ions "leak" back through the cell wall by diffusion. a. How much work must be done to move one sodium ion from the inside of the cell to the outside? b. At rest, the human body uses energy at the rate of approximately 100 W to maintain basic metabolic functions. It has been estimated that 20% of this energy is used to operate the sodium pumps of the body. Estimate to one significant figure the number of sodium ions pumped per second.

3. Living cells "pump" singly ionized sodium ions, Na+, from the inside of the cell to the outside across the membrane potential AVmembrane Vin - Vout= -70 mV. It is called pumping because work must be done to move a positive ion from the negative inside of the cell to the positive outside, and it must go on continuously because sodium ions "leak" back through the cell wall by diffusion. a. How much work must be done to move one sodium ion from the inside of the cell to the outside? b. At rest, the human body uses energy at the rate of approximately 100 W to maintain basic metabolic functions. It has been estimated that 20% of this energy is used to operate the sodium pumps of the body. Estimate to one significant figure the number of sodium ions pumped per second.

College Physics

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter1: Units, Trigonometry. And Vectors

Section: Chapter Questions

Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...

See similar textbooks

Similar questions

Resources Give Up? Under certain circumstances, potassium ions (K†) in a cell will move across the cell membrane from the inside to the outside. The potential inside the cell is -75.5 mV and the potential outside the cell is zero. What is the change in the electrical potential energy of a single potassium ion as it moves across the membrane? change in potential energy: Does the potential energy of the potassium ions increase, decrease, or remain the same as the ions move from the inside to the outside? O decrease remain the same increase
Q3. Two parallel-plate capacitors, 3.0 uF each, are connected in parallel to a 10 V battery. One of the capacitors is then squeezed so that its plate separation is 50.0% of its initial value. Because of the squeezing. (a) how much additional charge is transfered to the capacitors by the battery and (b) what is the increase in the total charge stored on the capacitors?
A 2000-kg electric car uses a 350-V battery pack. The car starts from rest and 4000 C flows from the battery. What's the maximum speed the car can reach during this time? Unload
Consider the circuit below. We have C1 = 10. pF, C2 = 20. pF, C3 = 30. pF, and V = 6.0 V. Answer the questions to follow regarding this circuit. i. What is the charge on C3? ii. What is the potential across C1? iii. What is the charge on C2? iv. What is the total energy stored in this system of capacitors?
A potential difference exists between the inner and outer surfaces of the membrane of a cell. The inner surface is negative relative to the outer surface. If 1.35 × 10-20 J of work is required to eject a positive sodium ion (Na+) from the interior of the cell, what is the magnitude of the potential difference between the inner and outer surfaces of the cell? magnitude of the potential difference:
1) Determine the change in chemical energy each second required to produce this increase in electric potential energy. 2) If there are roughly 7×10^11 of these cells in the body, how much chemical energy is used in pumping sodium ions each second? 3) Estimate the fraction of a person's metabolic rate used to pump these ions. Assume the metabolic rate to be 100 W.
A potential difference of 75 mV exists between the inner and outer surfaces of a cell membrane. The inner surface is negative relative to the outer surface. How much work is required to eject a positive sodium ion (Na+) from the interior of the cell?
Consider a parallel plate capacitor with metal plates, each of square shape of 1.00 m on a side, separated by 1.00 mm. What is the energy of this capacitor with 3.00×103 V applied to it? a. 3.98×10-2 J b. 5.08×1014 J c. 1.33×10-5 J d. 1.69×1011 J
Living cells "pump" singly ionized sodium ions, Na", from the inside of the cell to the outside to maintain a membrane potential AV membrane = Vin - Vout - 70 mV. It is called pumping because work must be done to move a positive ion from the negative inside of the cell to the positive outside, and it must go on continuously because sodium ions "leak" back through the cell wall by diffusion. a. How much work must be done to move one sodium ion from the inside of the cell to the outside? b. At rest, the human body uses energy at the rate of approxi- mately 100 W to maintain basic metabolic functions. It has been estimated that 20% of this energy is used to operate the sodium pumps of the body. Estimate-to one significant figure the number of sodium ions pumped per second.
K1 K2 A parallel plate capacitor consists of two square plates, each 1.2 cm long on a side, separated by a distance of .48 mm. The top half of the capacitor is filled by a material with a dielectric constant of k1 = 4.7 while the bottom half is filled by a material with a dielectric constant of K2 capacitor. These two capacitors are then in series.] 1.7. [Hint: Treat each half as a separate What is the capacitance of this device? 6.62E-12 Enter text [more..] How much energy will this capacitor store if it is charged by a 36 V battery. 4.28E-9
Electric Potential Energy (An lonic Crystal) 3. Four positive and four negative charges of equal magnitudes +Q are arranged alternately on the corners of a cube of side length d, +Q as drawn. This is a model of one cell of an ionic crystal such as -Q +Q salt, NaCl. a. Calculate the potential energy of this configuration. As d usual, take the energy to be zero infinitely far away from the charges. Express the energy in terms of k, Q, and d. d Hints: -Q +Q There are 12 pairs of opposite charges along the edges There are 12 pairs of like charges along the diagonals of each face There are 4 pairs of opposite charges along the cube's long diagonals b. In part (a), you should have determined that U < 0. Explain the relationship between this result and the observation that such crystals freely form in nature.
A potential difference of 90 mV exists between the inner and outer surfaces of a cell membrane. The inner surface is negative relative to the outer surface. How much work is required to eject a positive sodium ion (Na+) from the interior of the cell?