Cell Membrane, Membrane Transport, & Membrane Potential Part 3

Question 1

electrochemical gradient

Answer 1

two gradients for the passive transport of charged substances across the membrane

Question 2

electrochemical gradient formula

Answer 2

FDRion= (deltaEC)(T)(# of ion channels)(probability ion channels are open)

Question 3

chemical gradient

Answer 3

ions will move passively down concentration gradients

Question 4

electrical gradient

Answer 4

ions will move passively down electrical gradients

Question 5

strengths of the electrical gradient depends on the

Answer 5

valence of the Ion and magnitude of the membrane potential

Question 6

passively down electrochemical gradient (2)

Answer 6

chemical gradient

electrical gradient

Question 7

Na+ will move passively into the cell through

Answer 7

channels down its electrochemical gradient

Question 8

equilibrium potential (Eion)=

Answer 8

Vm that creates a ΔE that is equal in strength but opposite in direction of the ΔC (ΔE-ΔC=0)

Question 9

electrochemical equilibrium

Answer 9

no net movement through channels via facilitated diffusion

Question 10

the nest equation calculates the

Answer 10

equilibrium potential (E) when ion concentrations are known

Question 11

Eion (mV) =

Answer 11

(61/Z) log ([ion]ECF / [ion]ICF)

Z= ion valence 
61= magic number (universal gas constant, temperature, faraday constant, etc)

Question 12

At a cell’s resting membrane potential, the equilibrium potentials for Na+, K+, Cl- & Ca++ are such that when an ion channel for one of these ions opens,

Answer 12

the ions follow their concentration gradient

Question 13

ion movement affects

Answer 13

Vm

Question 14

stimulate a cell and open

Answer 14

Na+ channels

Question 15

what direction will Na+ move down its EC gradient?

Question 16

what happens to Vm as Na+ moves?

Question 17

depolarization

Answer 17

Vm becomes less negative than rest

Question 18

repolarization

Answer 18

Vm change that restores resting Vm

Question 19

hyperpolarization

Answer 19

Vm becomes more negative than rest

Question 20

repolarization

Answer 20

Vm change that restores resting Vm

Question 21

When Ion moves down EC gradient, Vm moves toward Eion, decreasing the —decreasing rate of —

Answer 21

EC gradient for ion movement and subsequently

ion movement via facilitated diffusion

Question 22

determinants of resting membrane potential

Answer 22

1. relative ion permeabilities

2. Na/K ATPase activity

Question 23

Na/K ATPase activity (2)

Answer 23

maintains ΔC for Na+ and K+

Electrogenic (2K+/3Na+)

Question 24

To change membrane potential, (2)

Answer 24

1. Change the membrane’s permeability to an ion (open/close a channel, or change activity of an active transporter)
2. Change the ion concentration gradient across the membrane

Question 25

Hyperkalemia (an increase in blood K+

concentration) (2)

Answer 25

 When K+ concentration outside of the cell increased,
the force of the concentration gradient is lessened.
 Less K+ exits cell down ΔEC and membrane