Membrane Potential Homework: Calculating [Na+] Inside Cell

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SUMMARY

The discussion focuses on calculating the intracellular sodium ion concentration ([Na+]) in a biological cell immersed in a 50mM NaCl solution at 37°C, where the cell membrane is selectively permeable to Na+ ions. At equilibrium, a potential difference of 54.9mV is observed, indicating that the inside of the cell is more positive than the outside. To find the [Na+] inside the cell, the Nernst equation can be applied, which relates the concentration gradient of ions to the membrane potential. The negligible transfer of Na+ ions allows for the assumption that the total concentration remains effectively unchanged during the measurement.

PREREQUISITES
  • Understanding of the Nernst equation for calculating equilibrium potential
  • Knowledge of membrane permeability and its effects on ion distribution
  • Familiarity with concepts of concentration cells in electrochemistry
  • Basic principles of cellular biology regarding ion transport
NEXT STEPS
  • Study the Nernst equation and its application in biological systems
  • Research the role of membrane permeability in ion concentration gradients
  • Explore the concept of concentration cells and their significance in electrochemistry
  • Investigate the physiological implications of sodium ion concentration in cellular functions
USEFUL FOR

Students in biology or biochemistry, educators teaching cellular physiology, and anyone interested in the electrochemical properties of cells and ion transport mechanisms.

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Homework Statement



a biological cell is immersed in a 50mM solution of NaCl at 37C. the cell's membrane is permeable only to Na+ ions. When the system reaches equilibrium, a potential diff of 54.9mV is measured between the inside and the outside of the cell where the inside has the higher( more positive potential.

Calculate [Na+] inside the cell, assuming the amount of Na+ ions transferred is negligible compared to the total amoiunt of Na+ ions in the solution.

Can anyone tell me where to start?
 
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