Facilitated Diffusion:

Question 1

Do all substances diffuse across the cell membrane at the same rate?

Answer 1

= no
= centre is hydrophobic
= hydrophobic molecules can diffuse rapidly
= hydrophilic molecules cannot diffuse across the membrane

Question 2

Why is it a problem that hydrophilic molecules cannot diffuse across the cell membrane?

Answer 2

=required for processes inside the cell
= cells use facilitated diffusion

Question 3

What happens in facilitated diffusion?

Answer 3

= hydrophilic substances diffuse across the cell membrane by protein molecules
= allow the hydrophilic substances to cross the membrane without interacting with the hydrophobic centre

Question 4

What are carrier proteins?

Answer 4

= intrensic protein
= have a binding site for a specific chemical- when the chemical binds the teritary structure changes and brings it across the cell membrane + released

Question 5

What are protein channels?

Answer 5

= central pore
= lined with hydrophilic amino acids + water
= hydrophilic substances can pass through the channel from one side to the other
=

Question 6

What are some key points for protein channels?

Answer 6

= protein channels are selective for the chemicals that can pass through it
= only certain chemicals can pass through each type of protein channel
= other protein channels can only be opened by a trigger
=

Question 7

What are some key points about facilitated diffusion?

Answer 7

= type of diffusion
= still from a high concentration to a low concentration
= energy is still not required