Membrane Potential I Flashcards Preview

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Flashcards in Membrane Potential I Deck (30):
1

What will happen if the membrane is permeable to only one ion and impermeable to the counterion?

an electrical charge is established

1

How much is one mole?

6.02x10^23

2

An imbalance in the number of cations and anions inside a cell produces the ____.

membrane potential

2

What does z stand for in the Nernst Equation?

valence of the ion in question

2

If an ion is at equal concentrations across a membrane, what will be its equilibrium potential?

zero

3

The ion concentration difference and the electrical potential difference across the membrane govern ______.

passive movement of an ion across the membrane

5

If the membrane is ______ to both Na+ and Cl-, nothing will happen and the cell will survive.

impermeable

5

What does T stand for in the Nernst Equation?

temperature

6

The passive movement of an ion across the membrane is governed by two forces: _____ and _____.

its concentration difference; the electrical potential difference across the membrane

7

What does R stand for in the Nernst Equation?

the gas constant

9

____ charge is much stronger than ____ charge.

Electrical; osmotic

11

How do animal cells solve the problem of controlling their volume?

by surrounding themselves with an external solution that also contains nonpermeating molecules

12

What if Vm is not the same as ECl?

either a) the membrane is impermeable to the ion or b) the ion must be pumped across the membrane

14

If the membrane is impermeable to both Na+ and Cl-, _____ and the cell _____.

nothing will happen; will survive

15

The electrochemical gradient is made by?

The ion concentration difference and the electrical potential difference across the membrane in a cell

16

If the membrane is permeable to both Na+ and Cl-, they both will ______ and the cell will ______.

diffuse into the cell; burst

17

A beaker of H2O will osmotically support a column of 1.0M glucose _____ high.

900 feet

17

What does E stand for in the Nernst Equation?

equilibrium potential in millivolts

18

E = (RT/zF) lne (Co/Ci)

the Nernst Equation

19

What does F stand for in the Nernst Equation?

the Faraday constant

21

Bulk solutions are always electrically _____.

neutral

22

What does Co stand for in the Nernst Equation?

outside concentration of the ion

22

What is the equilibrium potential?

electrical potential difference across the membrane that must exist if the ion is to be at equilibrium

24

What does Ci stand for in the Nernst Equation?

inside concentration of the ion

25

the Nernst Equation

E = (RT/zF) lne (Co/Ci),

26

If the membrane is ______ to both Na+ and Cl-, they both will diffuse into the cell and the cell will burst.

permeable

27

What if Vm is the same as ECl?

no pump is needed to maintain the equilibrium

28

Membrane potentials are produced by?

an imbalance in the number of cations and anions inside a cell

29

The ion concentration difference and the electrical potential difference across the membrane combined make ______.

the electrochemical gradient

30

How do cells maintain ionic equilibrium?

for every charged ion that enters the cell, one of the same charge is pushed out of the cell because like repels like