2.5 Facilitated Diffusion Flashcards
What is facilitated diffusion?
Diffusion of substances across a membrane through a trans membrane protein molecule, allowing water soluble ions and molecules such as glucose and amino acids through
What are the 2 types of facilitated diffusion?
Channel protein
Carrier protein
What is a channel protein?
A water filled pore/channel in the membrane
What does a channel protein allow?
Charged substances tot diffuse across the membrane
What can channel proteins be?
Can be gated (open or closed) allowing the cell to control entry and exit of ions
What do carrier proteins span?
The whole membrane
Where does the substance bind on a carrier protein?
The side where it is at a high concentration to be released where it is at a low concentration
What do carrier proteins have?
A bonding site for a specific solute
What do carrier proteins flip between?
Two states so the site is alternating so it is open to both sides of the membrane
What do carrier proteins sometimes have?
Two binding sites to carry two molecules at once (cotta sport)
What must happen for cotransport to take place?
Both molecules have to be present
What does facilitated diffusion have in common with diffusion?
It is a passive process that occurs down a concentration gradient
