Resting Membrane Potential Flashcards Preview

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Flashcards in Resting Membrane Potential Deck (23)
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1
Q

All cells in the resting stage exhibit a voltage across their membrane. This is called

A

The resting membrane potential

2
Q

What molecule is in high extracellular concentration and low intracellular concentration?

A

Sodium (Na)

3
Q

Why is sodium higher on the outside of the membrane than it is on the inside of the cell?

A

Because the membrane is poorly permeable to sodium.

4
Q

What molecule is in high concentration in the cell and low concentration in the extracellular fluid?

A

Potassium (K)

5
Q

Why is potassium higher on the inside of the membrane than it is on the outside of the cell?

A

Because the membrane is permeable to potassium.

6
Q

What is the typical range of resting membrane potential that all body plasma membranes exhibit?

A

Typically ranges from -50 to -100 milivolts (mV) depending on cell type.

7
Q

What does the minus sign before the voltage indicate?

A

That the inside of the cell is negative compared to its outside.

8
Q

This voltage (or charge separation) exists only

A

At the membrane.

9
Q

If all the negative and positive charges in the cytoplasm were added up, what would be found?

A

You would find that the cell interior is electrically neutral. Likewise for the extracellular fluid.

10
Q

The most well-studied carrier (pump) called Na+ -K+ ATPase, located in all plasma membranes, and involved in primary and secondary active transport of nutrients and ions.

A

Sodium potassium pump

11
Q

Na+ and K+ channels allow ___ ____ down concentration gradients

A

Slow leakage

12
Q

Na+ and K+ pump works as antiporter; pumps against Na+ and K+ gradients to maintiain high interacellular __ concentration and higher extracellullar ___ concentration

A

K+

Na+

13
Q

The Na+ and K+ pump maintains electrochemical gradients essential for functions of

A

Muscle and nerve tissues, and allows all cells to maintain fluid volume

14
Q

Na+ and K+ pump is an example of

A

Primary active transport

15
Q

Step 1 of Na+ and K+ pump?

A

3 cytoplasmic Na+ bind to pump protein

16
Q

Step 2 of Na+ and K+ pump?

A

Na+ binding promotes hydrolysis of ATP. The energy released during this reaction phosphorylates the pump.

17
Q

Step 3 of Na+ and K+ pump?

A

Phosphorylation cause the pump to change shape, expelling the Na+ to the outside.

18
Q

Step 4 of Na+ and K+ pump?

A

Two extracellular K+ bind to the pump

19
Q

Step 5 of Na+ and K+ pump?

A

K+ binding triggers release of the phosphate. The dephosphorylated pump resumes its original conformation.

20
Q

Step 6 of Na+ and K+ pump?

A

Pump proteins binds ATP; releases K+ to the inside, and Na+ sites are ready to bind Na+ again. The cycle repeats.

21
Q

What is the point of the Sodium potassium pump?

A

It is used to move sodium and potassium AGAINST its concentration gradient. Going from an area of high concentration to low concentration takes ATP.

22
Q

Why are all cells considered polarized/

A

Because all body plasma membranes exhibit a -50 to -100 millivolts depending on cell type.

23
Q

The resting membrane potential is largely determined by ___ because at rest, the membrane is much more permeable to K+ than Na+.

A

K+