Membrane Potential

Question 1

Define chemical driving force

Answer 1

chemical force on an ion is only due to the chemical concentration gradient. Ek

Question 2

Define Electrical driving force

Answer 2

Ions move down their chemical concentration gradients, they can generate electrical forces.

• Positive ion moves out of cell, the cell’s membrane potential becomes more NEGATIVE
• Negative ion moves out of cell, the cell’s membrane potential becomes more POSITIVE
  e. g positive ions will be drawn into a cell by electrical force when membrane potential is negative

Question 3

Equalibirum potential gives the strength of the _______ force on the ion

Answer 3

Chemical force

Question 4

Vm

Answer 4

membrane potential

Question 5

Define the Role of Cloride

Answer 5

• in cells where no net pumping of Cl than Vm = Ecl
• conc of Cl- is always lower inside the cell than in the extracellular fluid fluid
• Ecl- is more negative than Vm causes hyperpolarization

Question 6

What affect does an increase in extracellular K+ have on the membrane potential

Answer 6

causes depolarization