1. Neurones

Question 1

What is the resting state of a membrane potential ?

Answer 1

Outside of membrane is positively charged compared to the inside of the membrane.

Because more positive ions out side the cell than inside.

Membrane is POLARISED- difference In charge

Voltage across membrane when it’s at test id called resting potential

Question 2

What is the difference in charge called ?

Answer 2

Potential difference

Voltage

Question 3

What is the normal number for resting potential ?

Answer 3

-70 mV

Question 4

How is the resting potential created and maintained ?

Answer 4

Sodium potassium pump

And

Potassium ions channels

Question 5

What type of transport/ diffusion does the sodium potassium pump use ?

Answer 5

Active transport - ATP needed

3 sodium ions out of neurone

2 potassium ions in

Question 6

What type of transport/ diffusion does the potassium ions channels use ?

Answer 6

Facilitated diffusion of potassium ions out of neurone down conc gradient

Question 7

Stage one

Answer 7

The sodium potassium pump pumps 3 sodium ions out of membrane.

The membrane isn’t permeable to sodium ions so they cannot diffuse back in membrane.

This creates sodium ion electrochemical gradient - conc gradient of ions as more postive ions located outside of membrane than inside

Question 8

Step 2

Answer 8

The sodium potassium pump also pumps 2 potassium ions into membrane

Question 9

Step 3

Answer 9

The potassium ions channels are open at resting state so potassium diffuses out of membrane but can also diffuse back through as membrane is permeable to potassium