Resting Membrane Potential LO4

Question 1

Resting Membrane Potential

Answer 1

Potential energy (called voltage and measured in volts) that
exists across the plasma membrane resulting from
separating opposite charges by the plasma membrane
5 neg, 5 pos on inside and outside
ECF is slightly more positive than ICF

Question 2

Ion concentrations and leakage channels

Answer 2

• ECF: higher concentration of Na+
• Na+ moves into cell through Na+ leakage channel
  ICF: higher concentration of K+
• K+ moves out of cell through K+ leakage channels
• plasma membrane contains more K+
  leakage channels than Na+
  so more K+ ions move out of the cell than Na+ moves in.

Question 3

Resting Membrane Potential generated by

Answer 3

the movement of potassium K+ ions from ICF
to ECF through K+
leakage channels in plasma membrane leaving
the outside of plasma membrane positive relative to the inside

Question 4

Resting membrane potential maintained by

Answer 4

the active transport of ions using the carrier protein called the Na+/K+ ATPase pump
to stop the ions reaching equilibrium
the Na+ /K+ ATPase pump:
➢pumps out 3 Na+ ions
➢pumps in 2 K+ ions