Membrane Potentials Flashcards Preview

Physiology 2002 > Membrane Potentials > Flashcards

Flashcards in Membrane Potentials Deck (26):
1

What is Valence?

The charge on an ion given as z

2

How do we calculate valence?

z = - [C(ion)] / [C(e-)]

C(ion) = Coulombs of ion
C(e-) = Coulombs of electron

3

What is Faraday Constant?

F = 96485 C/mol

4

How do we calculate charge (q) of n moles with a valence z?

q = zFn
q = charge, z = valence, F = Faraday constant, n = moles

5

What is Volatge?

Electrical potential abbreviated V

6

What is the formula for Current (i) with respect to time?

i = q/t
i = Current
q = charge
t =time

7

What is the Nernst Equation?

μ(x) = nRT * ln( [x]1 / [x]2 )
μ(x) = Chemical potential energy of x

8

How do we calculate the electrical potential energy (EPE)?

μ(e) = zFn * V

9

How do we calculate the Voltage using the Nernst equation and the formula for EPE?

V = - (RT/zF) * ln( [x]in/[x]out )

NOTE: this gives the answer in V not mV

10

What is the general resting potential for cells?

-70mV

11

What is the formula for capacitance?

q = CV in Faradays

12

What is the capacitance of a normal cells?

~ 1.3 x 10^-11 F

13

Electrogenic potential is created by ________________.

Active Transport

14

What is the Goldman equation?

V = -RT/F * ln( {Pk[K]in + PNa[Na]in + PCl[Cl] out} / {Pk[K]out + PNa[Na]out + PCl[Cl]in} ) in V not mV

15

What is Ve?

Equilibrium Potential

16

Flux is equal to?

j = i/zFA
i = current, j = flux, z = valence, F = Faraday's constant and A= area

17

At Ve there is __________

No flow

18

Between 0 and Ve the ________________ will win

The Chemical Gradient will win

19

If we have

The Electrical Gradient will win

20

Current is given as the flow of __________charge into the cell. Therefore, the flow of ______ into the cell will be classed as an outward current.

Positive
Anions

21

What is Ohm's law?

V = IR
V= voltage, I= Current and R= Resistance

22

What is conductance?

Conductance (G) is how easy it is to move charge, unit is Siemens (S)

23

If only voltage moves an ion we can expect:

Ix = Gx * V
Ix = Current of x
Gx = Conductance of x

24

What is Unitary Conductance (g)?

The number of channels in the membrane and the proportion that are open

25

How does voltage change cell conductance?

By opening ion channels

26

The Unitary Conductance of an ion channel is it's __________________.

Open conductance