Resting membrane potential

Question 1

What is resting membrane potential?

Answer 1

Voltage difference across the cell membrance at rest, it exist in all cells.

Question 2

What is the RMP voltage?

Answer 2

-70mv to -90mv.

Question 3

What does the sodium potassium ATPases do?

Answer 3

1.These pump 3 Na+ ions out the cell and pump 2 K+ into the cell
2.This makes the outside negative and the inside of the cell positive
3.This also makes the cells just a little bit negative.

Question 4

What does the leaky potassium channels do?

Answer 4

1.The leaky potassium channels allow K+ ions to move in and out of the cell freely
2.Because the concentration of K+ ions is high inside the cell it want to go to the outside of the cell
3.The K+ ions inside go through the channels to the outside but they are bided with anions
4.The anions can be phosphates or proteins, these are negatively charged and too big so they cant leave the cell they must maintain in the cell
5.The anions will make the cell very negative -5mv to -90mv

Question 5

What does the leaky sodium channels do?

Answer 5

1.The leaky sodium channels allow Na+ ions from the outside into the cell (High to low concentration)
2.However it is not as much as the K+ ions allowed in
3.It will make the cell sighly postive -90mv to -70mv

Question 6

When is Nernst potential used?

Answer 6

It is used when the K+ moving out the cell going down the concentration gradient or when the K+ is moving into the cell.

Question 7

Nernst Potential Equation

Answer 7

EK+=61.5/z
61.5xlog 10(?/?)=
Kout/Kin

Question 8

Graded potental threshold?

Answer 8

-55MV

Question 9

Graded potential positive?

Answer 9

1. pre synaptic neurons excite the post synapic by releasing neurotransmitter e.g glutamate
2. Glutamate binds to the pockets opening the gates allowing Ca+ or Na+ ions into the cell
3. When these ions join the cell it is more positive going from -70MV to -55MV

Question 10

Graded potentials Negative?

Answer 10

1.Neutrotransmitter e.g Gaba binds to the pockets
2.Which open the gates allowing Cl- in the cell or K+ ions out the cell
3.Which results in the cell becoming negative -70MV to -90MV

Question 11

How does action potentials work?

Answer 11

1. The threshold -55MV activates the sodium voltage gate channels and open the gates up
2. Once the gates are open the Na+ ions are rushed into the cell making the voltahe go from -55MV to +30MV( This means inside the cell is positive)
3. The positive ions move down the axon to the next sodium voltage gate channels and it opens allowing more Na+ ions ( This happens one more time so in total 3x)
4. The positive ions have a positive voltage of +30MV which activates the calcium voltage gate channels which allow Ca+ ions into the cell
5. Once the Ca+ ions are in the cell it causes fusion of vesicles with the cell memebrane (Ca+ ions makes the cell positive)