Question

Consider a cell in which Cl- distributes passively across the membrane according to the membrane potential. The resting membrane potential in this cell is measured to be -60 mV. If the extracellular Cl- concentration is 100 mM, then the intracellular Cl- concentration is:

Answer 1

Answer:

1000 mM

Explanation:

Using V = -60 mV㏒₁₀[K/K'] where V = membrane potential = -60 mV, K = intracellular concentration = unknown and K' = extracellular concentration = 100 mM

So, V = -60 mV㏒₁₀[K/K']

-60  mV = -60 mV㏒₁₀[K/K']

dividing both sides by -60mV, we have

-60  mV/-60 mV = ㏒₁₀[K/K']

㏒₁₀[K/K'] = 1

taking antilogarithm of both sides, we have

[K/K']  = 10¹

multiplying both sides by K', we have

K = 10K'

K = 10 × 100 mM

K = 1000 mM

So, the intracellular Cl- concentration is 1000 mM