Student Introduction 2 Cell Membrane, Membrane Transport, and Membrane Potential PART 2

Question 1

what is the function of membrane potential

Answer 1

-creates electrical gradients for movements of ions into/out of cells
- opens or closes gated ion channels
- regulates exocytosis

Question 2

what is the formula for facilitated diffusion rate of ions down an electrochemical gradient

Answer 2

(change in electrochemical gradient)(T)(number of ion channels)(Probability that the channels are open)

Question 3

what does the strength of the electrical gradient depend on

Answer 3

the valence of the ion and the magnitude of the membrane potential

Question 4

what is the formula for equilibrium potential

Answer 4

change in electrical gradient minus the change in chemical gradient equals zero

Question 5

what does the nernst equation calculate

Answer 5

equilibrium potential when ion concentrations are known

Question 6

what is the nernst equation

Answer 6

E(ion) (mV) = 61log/Z ([ion]ECF/[ion]ICF)

Question 7

what is depolarization

Answer 7

membrane potential becomes less negative than rest

Question 8

what is repolarization

Answer 8

membrane potential change that restores resting membrane potential

Question 9

what is hyperpolarization

Answer 9

membrane potential becomes more negative than rest

Question 10

how is the electrochemical gradient and ion movement affected as membrane potential moves towards equilibrium

Answer 10

electrochemical gradient for ion movement decreases and subsequently decreases rate of ion movement via facilitated diffusion

Question 11

what are the determinants of resting membrane potential

Answer 11

-relative ion permeabilities
-sodium potassium ATPase activity

Question 12

how would you change membrane potential

Answer 12

-change the membrane’s permeability to an ion by opening or closing a channel or changing the activity of an active transporter
-change the ion concentration gradient across the membrane