Facilitated diffusion Flashcards
1
Q
What is the phospholipid bilayer a barrier to?
A
Polar molecules + ions
2
Q
How do polar molecules get into cells?
A
Through protein channels - known as facilitated diffusion
Makes membrane selectively permeable
3
Q
What concentrations do molecules move from?
A
High to low, until equilibrium is reached
4
Q
Explain the effect of channel proteins:
A
Specific to 1 molecule/ion
The more channel proteins, the higher the rate of diffusion
5
Q
Explain the effect of carrier proteins:
A
Changes shape when specific molecule binds
6
Q
Does facilitated diffusion require energy?
A
No - doesnt go against conc gradient
7
Q
What does the rate of facilitated diffusion depend on?
A
- Temp
- Channel proteins
- Conc gradient
- Membrane surface area
- Membrane thickness
