L4 Equilibrium Potentials

Question 1

What is the ratio of K+ inside:outside

Answer 1

150mM inside

5mM outside

Question 2

What is the ratio of Na+ outside:inside the cell?

Answer 2

15 mM inside

150mM outside

Question 3

What is the ratio of Cl- outside:inside the cell?

Answer 3

120mM outside

10mM inside

Question 4

At rest, there are leaky K+ and Na+ channels. What are they doing?

Answer 4

K+ is leaking out of the cell a LOT

Na+ is leaking into the cell a little

Question 5

When will the net flux of an ion stop?

Answer 5

When the electrical gradient and chemical gradient of it are equal

Question 6

What does the Nernst equation calculate?

Answer 6

Calculates the equilibrium potential for an ion at a given concentration difference across the membrane (AS LONG AS THE MEMBRANE IS PERMEABLE TO THAT ION)

-determines the electrical forces required to just balance a given diffusion force ([ion in]-[ion out]

Question 7

What is the Nernst Equation?

Answer 7

E ion=

(60/z) log([ion out]/[ion in])

Question 8

What percentage of ions move across the membrane during changes in membrane potential

Answer 8

Infinitesimally small