Changing membrane potential

Question 1

What is the purpose of changing membrane potential?

Answer 1

Cell signalling

Question 2

What are some examples of cell signalling produced by changing membrane potential?

Answer 2

Action potentials

Secretion of hormones, neurotransmitters

Muscle contraction

Question 3

What are the two ways in which the membrane potential can change?

Answer 3

Depolarisation

Hyperpolarisation

Question 4

What is meant by depolarisation?

Answer 4

Decrease in size of membrane potential from normal value

becomes less negative

Question 5

What is meant by hyperpolarisation?

Answer 5

Increase in size of membrane potential from normal value

becomes more negative

Question 6

What is responsible for changing the membrane potential?

Answer 6

Changing permeability of plasma membrane to different ions
by opening up different ion channels

Or by changing ion concentrations intracellularly or extracellularly

Question 7

What effect will opening up potassium and chloride ion channels have on the membrane potential?

Answer 7

Hyperpolarisation

Question 8

What effect will opening up sodium and calcium ion channels have on the membrane potential?

Answer 8

Depolarisation

Question 9

What is conductance?

Answer 9

Refers to how permeable the plasma membrane is to a specific ion