Module 5 - Electrochemical gradients

Question 1

Ion diffusion speed

Answer 1

Depends on the distance and dimensions moved by the molecules

Question 2

The three dimensions of molecules movement

Answer 2

1 dimensional - movement along DNA
2 dimensional - membrane movement
3 dimensional - cytosol (liquid) movement

Question 3

How do dimensional movements apply to molecule movement?

Answer 3

Catalysts/signalling molecules (GPCRs) give things a 2D surface to bind to

Signalling molecules have larger ranges if they are not bound to membranes

Question 4

Ion diffusion relationship with area and concentration

Answer 4

Molecules moving across an interface is proportional to

Question 5

Electrochemical gradient: what is it and what factors affect it?

Answer 5

The total gradient of ion movement

Diffusion gradient - electrophoretic movement gradient (the ion movement under an electric field)

Question 6

What affects the rate of ion movement?

Answer 6

• The size of the electrochemical gradient
• The nature of the ion
• Number of open ion channels
• The properties of the ion channel

Question 7

Ohm’s law

Answer 7

Voltage (V) = Current (I) x resistance (R)

Current (I) = Voltage (V) x conductance (where conductance= 1/R)