L4 Membrane Permeability & Transport

Question 1

Small uncharged polar molecules?

Answer 1

Only some will pass - usually need support

Question 2

Large uncharged molecules?

Answer 2

Can’t really pass

Question 3

Ions

Answer 3

Can’t pass

Bc they interact with polar water molecules

Question 4

2 types of passive transport proteins?

Answer 4

Channel

Carrier protein (has specific binding site)

Question 5

2 types of active coupled transport? And what is their mode of energy?

Answer 5

Symport
Antiport

They use the free energy from the movement of an ion down the electrochemical gradient

Question 6

3 types of active transport?

Answer 6

P type pump
ABC transporter
F type proton pump

Question 7

How is the P type pump different to ABC transporter?

Answer 7

P type pump pumps ions, eg k/na pump

Abc transporter pumps small molecules and releases charged species

Question 8

What is the Na/K pump?

Answer 8

Requires ATP

Goes against conc gradient

Potassium from ATP->ADP changes its conformation to expose na

3na:2k

Question 9

The different types of ion channels?

Answer 9

Voltage gated
Ligand gated (intra and extracellular)
Mechanically gated

Question 10

Where does the membrane potential arise from?

Answer 10

K+ leak channels

Creates more -Ve potential inside cell

K+ flow back in

Question 11

What is the resting membrane potential?

Answer 11

It is the voltage at which the k+ electrical gradient is zero.

Usually it is -70mV meaning inside the cell is more negative.

Question 12

Hydrophobic molecules?

Answer 12

Can pass membrane