membrane potential

Question 1

what is a membrane potential

Answer 1

membrane potential(Em) = separation of opposite charges across a membrane, given name potential because the charge has potential to work
(membrane itself not charged)

Question 2

other than opposite charges on each side what else is required to have a membrane potential

Answer 2

a difference in the charge on each side, eg +10 on one side and -10 on the other

Question 3

what does the magnitude of the membrane potential depend on

Answer 3

the greater the charge on each side of the membrane, the greater the membrane potential is

Question 4

what is an action potential

Answer 4

excitable cells such as nerve or muscle cells are able to produce rapid, transient potential changes when excited, this is called action potential

Question 5

what is a resting potential

Answer 5

the constant membrane potential in non-excitable cells and excitable cells at rest

Question 6

what is the cause/what contributes to the membrane potential

Answer 6

Em is due to differences in conc. and permeability of key ions on each side of the membrane, such as Na+,K+,

Question 7

describe the conc. gradient and electrical gradient of the Na+ and K+ ions

Answer 7

conc. gradient = Na+ is inward and K+ is outward

electrical gradient = both are cationic(+ve ions) so electrical gradient will always be towards -ve side of membrane

Question 8

describe the permeability of K+ and Na+ at resting potential

Answer 8

K+ is 100x more permeable then Na+ at resting potential

Question 9

describe the importance of the membrane potential(Em)

Answer 9

specialised use of Em in nerve and muscle cells allows them to rapidly and transiently alter their membrane permeabilities in response to stimuli
used for nerve impulses in nerves and contraction of muscles