resting potentials

Question 1

explain how a resting potential is established and maintained

Answer 1

• Na+/K+ pump actively transports (pumps) 3Na+ out of the cell causes an increase in Na+ concentration and they can’t diffuse back into cell because Na+ channel protein is closed
• at the same time Na+/K+ pump actively transports 2K+ into the cell
• K+ channel proteins are open so K+ diffuses down concentration gradient out of cell

electrochemical gradient with higher concentration of positive ions outside compared to inside
so the membrane is polarised with a potential difference = - 65 mV (-70 mV)

Question 2

what is the potential difference of the membrane when polarised at the resting potential

Answer 2

-70mV

Question 3

what are the units for potential difference

Answer 3

mV