The following solution measurements were made on the fluids inside and outside o
ID: 317491 • Letter: T
Question
The following solution measurements were made on the fluids inside and outside of a nerve cell that has a membrane potential of -70 mV.
Ion
ICF( I ) mmol/L
ECF (o) mmol/L
Na
30
140
K
100
4
Cl
5
100
Calculate the equilibrium potential for each ion using the Nernst equation assuming 2.3 RT/F = 60 mV.
A. Which ion is closest to electrochemical equilibrium? Why?
B.Compare the relative conductivity or permeability for each ion. Which ion is most permeable?
PLEASE SHOW ALL WORK AND EXPLAIN!! DONT ANSWER IF YOU WONT COMPLETE THE ENTRE QUESTION (AKA ALL PARTS OF QUESTION)!!
Ion
ICF( I ) mmol/L
ECF (o) mmol/L
Na
30
140
K
100
4
Cl
5
100
Explanation / Answer
Answer: the Nernst equation is used to determine the equilibrium potential for various ions:
(i) If the ion in question is K+, the Nernst equilibrium potential for K+ (VK) will be: Vk= RT/+1Fln similarly nernst equation derived for Na ion which is also positively charged and chloride (cl-) which is negatively charged. The equilibrium potential for Na+ is VNa= 0.039556, similarly for K+ is Vk= -0.08265 and chlorine has one negative charge so whose equilibrium constant will be Vcl= -0.07692.
A: Cl- is closest to electrochemical equilibrium as considerable energy is expended by cells to move Na+ and K+ actively so that they have the relative concentrations shown. The Cl- then adjusts passively in response to the resulting electrical potential difference
B. Potassium ion is more permeable as it has positive charge and cell membrane by inner has negative charge so three atom of K+ ion enter into the cell and 2 Na+ in move out of the cell. thats why K+ ion has maximum permeability.