Tri A - Membranes and Ions

Question 1

Describe the concentration of Na+ inside and outside the cell

Answer 1

Inside = low
Outside = high

Question 2

Describe the concentration of K+ inside and outside the cell

Answer 2

Inside = high
Outside = low

Question 3

Describe the ionic strength inside and outside the cell

Answer 3

Inside = more negative
Outside = more positive

Question 4

Describe Excitable cells

Answer 4

Have the ability to alter membrane potential

Question 5

How do Excitable cells change their membrane potential?

Answer 5

Via gated ion channels

Question 6

Describe gated ion channels at rest

Answer 6

Gates closed, inside cell = -ve, outside cell = +ve –> membrane is polarised

Question 7

What causes hyperpolarisation

Answer 7

K+ gates are slow to close, excess K+ leaks out of the cell making it more negative until the gates are completely closed

Question 8

What is Membrane Potential?

Answer 8

The difference in electric potential between the interior and the exterior of a biological cell.