Resting Potential

Question 1

When is an axon at rest

Answer 1

When not conducting a nerve impulse

Question 2

Role of Na+/K+ pump in the resting potential

Answer 2

Enzyme Na+/K+ ATPase that uses ATP to pump 3 Na+ out of the axon and 2K+ into the axon.
Na+ conc outside> inside
Membrane is impermeable to Na+ so can’t diffuse back

Question 3

Role of diffusion of K+ in resting potential

Answer 3

K+ passively diffuses through K+ protein channels to extracellular space
bc K+ conc outside< inside axon

Question 4

Potential difference formed

Answer 4

Electrochemical gradient formed
Na+ ions conc > inside
Outside has more positive charged ions
Potential difference of -70mv
Inside more negative
Polarised
Resting potential

Question 5

How is resting potential maintained

Answer 5

Na+/K+ pump
Na+ ions (3x) leave and K+ enter (2x)
K+ diffuses out potassium channels
Membrane is impermeable to sodium ions (Na+ channels close)
Outside more positive than inside