For a vertebrate neuron you are studying at $30$ oC $,$ you have measured the following intracellular and extracellular concentrations $($concentrations are in mM$),$

although unfortunately you were unable to make accurate measurements of $[$Na$+]$s:

$[$K$+]$ in $=145\mathrm{.}5[$K$+]$ out $=4\mathrm{.}2$

$[$Mg$2+]$ in $=2\mathrm{.}2[$Mg$2+]$ out $=5\mathrm{.}4$

$[$Na$+]$ in $=?[$Na$+]$ out $=?$

$[$Cl$-]$ in $=7\mathrm{.}0[$Cl$-]$ out $=156\mathrm{.}0$

$[$A$-]$ in $=147\mathrm{.}4[$A$-]$ out $=0$

You determined that the membrane is impermeable to Mg $2+$ and A$-$

$.$ You have also determined that at rest, the permeability to K$+$ is $50$ times the permeability to Na $+,$ and the permeability to Cl$-$ is twice the permeability to Na$+.$

$($a$)$ Assuming the above is a complete list of solutes present in the intracellular and

extracellular solutions, calculate $[$Na$+]$ in and $[$Na$+]$ out $.$

$($b$)$ Calculate the membrane resting potential, Vrest $.$

$($c$)$ At the Vrest you calculated for part $($b$),$ what is the driving force on the chloride

ions $($DFCl$-)?$

$($d$)$ In which direction would the Cl $-$ ions carry current at Vrest $?$ In which direction

would Cl $-$ ions move?Steps for Posting a question