Membrane Transport

Question 1

What is permeability related to and why

Answer 1

If the molecule is hydrophobic the molecules can pass through the membrane

The greater the size and the more water soluble the molecule the less permeability

Question 2

True or false
Ions can freely pass through the lipid bilayer

Answer 2

False

Question 3

True or false
Large and small uncharged polar molecules are semi permeable

Answer 3

True

Question 4

What are the two types of transport proteins

Answer 4

Ion channels and transporters

Question 5

What are the different types of transporters

Answer 5

Passive transporters

Secondary active transporters

Primary active transporters
P-type, F- and v-type , ABC-type

Question 6

Which is higher inside or outside of the cell
Na+
K+

Answer 6

Na + lower in the cell than outside
K+ higher in the cell than outside

Question 7

What are the different classes of ion channels

Answer 7

Voltage gated
Ligand gated ( extracellular or intra cellular
Mechanically gated

Question 8

How do voltage gated ions channels work

Answer 8

By change in voltage

Question 9

How do ligand gated ion channels work

Answer 9

They are opened to respond of the binding of a ligand to the active site

Question 10

How do mechanically gated ions channels work

Answer 10

The respond to stress and stretch forces upon the cell membrane

Question 11

What type of molecules need transporters

Answer 11

Hydrophilic

Question 12

What are the main features of the passive transporters and how do they work

Answer 12

. Small hydrophilic molecules down their concentration gradients
. No energy required
. Uniport (one direction)
. No Hole (no aquas pore)
. Binding of the cargo molecule and conformational change helps the molecules move across

Question 13

How fast are passive transporters and why

Answer 13

Relatively slow because they are highly selective

Question 14

True or false
Passive transporters are saturable

Answer 14

True
It means they have a maximum rate of diffusion

Question 15

Give one example of a passive transporter

Answer 15

Glucose transporters (GLUT)
1,2,3,4,14
Slc2 class 1

Question 16

What are the two types of active transporters

Answer 16

Primary and secondary

Question 17

How do primary active transporters work

Answer 17

ATP hydrolysis
Pumps

Question 18

What type molecules do primary active transporters transport

Answer 18

Ions and small hydrophilic molecules

Question 19

True or false Primary active transporters can be called channels

Answer 19

False

Question 20

How do primary active transporters work

Answer 20

Using ATP hydrolysis which causes a conformational change and enables them to move to to other side

Question 21

True or false they can be uniporters ,symporters and anti porters

Answer 21

True

Question 22

Are they fast or slow and why

Answer 22

Slow as they are selective and also saturable

Question 23

What do v and f type pumps transfer

Answer 23

Protons (H+)

Question 24

Explain p type pumps

Answer 24

. They move cations
. The pump becomes phosphorylated when ATP is hydrolysed, this results in conformational change allowing ions to move from one side to another

Question 25

What is one primary example of p type pumps

Answer 25

Sodium and potassium -ATPase
Most abundant

And calcium-ATPase
In plasma membrane and in sarcoplasmic and endoplasmic reticular (serca)

Question 26

Where are v and f type pumps found

Answer 26

Organelles for v
Inside of organelle is more acidic by pumping h+
Inner mitochondrial membrane for F
For ATP synthesis.

Question 27

How do ABC transporters work

Answer 27

Using ATP binding and hydrolysis however this does not use phosphorylation.

Question 28

What is one important example of molecules transported via abc transporters

Answer 28

P-glyco protein
Pumps hydrophilic drugs non selective through cell membranes.

Question 29

How do secondary active transporters work (coupled transporters)

Answer 29

Both solutes must be present which means they can be symport and anti port the energy comes from the dissipation of the potential energy in the ion. One moves down it’s gradient in order for another molecule to move up its gradient.