Equations

Question 1

Ohm’s law

Answer 1

V = IR

Question 2

Nernst equation

Answer 2

E = (RT/zF) ln([C]ref/[C]test)

E - equilibrium potential
F - Faraday’s constant
[C] - ion concentration

Question 3

what is the Nernst equation used for?

Answer 3

calculate equilibrium potentials for a given ion

Question 4

three Nernst equation assumptions

Answer 4

• only one ion must be moving
• membrane must be completely permeable to the ion
• ion should be at equilibrium

Question 5

Nernst equation for monovalent cation at room temperature

Answer 5

E = 58log([C]out/[C]in)

Question 6

Nernst equation for monovalent cation at body temperature

Answer 6

E = 61log([C]out/[C]in)

Question 7

what is different about the Nernst equation when working out equilibrium potentials for anions?

Answer 7

use [C]in/[C]out

(negative charge, use reciprocal)

Question 8

why can λ = √[rm/(ro+ri)] be simplified to λ = √(rm/ri)?

Answer 8

ro (outside resistance) is negligible

Question 9

what is the name of the adapted Nernst equation?

Answer 9

Goldman-Hodgkin-Katz equation

Question 10

Goldman-Hodgkin-Katz equation

Answer 10

V = (RT/F) {ln[(Pk[K]o + PNa[Na]o + PCl[Cl]i)/(Pk[K]i + PNa[Na]i + PCl[Cl]o)]}

P - ion permeability
V - membrane potential

Question 11

what is the Goldman-Hodgkin-Katz equation used for?

Answer 11

calculating membrane potential of a cell, taking into account more than one ion concentration and relative permeabilities

Question 12

mean MEPP equation

Answer 12

m = np

m - no. of MEPP (minature end plate potential)
n - no. of quanta
p - probability of releasing quanta