across biological membranes. review for transport 1. what are the two parts of a solution? 2. in...
TRANSCRIPT
Review for Transport
1. What are the two parts of a solution?
2. In cells, what is normally the solvent?
3. How would you describe the activity of solute particles in solutions?
Simple Diffusion
Particles diffuse through lipid bi-layers to reach equilibrium
Mainly small, nonpolar
Facilitated Diffusion Membrane proteins carry materials
through the lipid bilayer.1. Particle binds to membrane protein.
2. Membrane protein changes shape.
3. Particle is released on the other side.
Osmosis Diffusion of water
• When solute cannot cross membranes to reach equilibrium, the solvent (water) does
• Water moves from where it is purest (hi conc.) to where it is least pure (lo conc.)
H2
O
H2
O
H2
OH2
OH2
O
H2
O
H2
O
H2
OH2O
H2O
H2O
H2OH2OH2O
H2O
H2O
Transport Review What two things are always true of
passive transport? What are the examples of passive
transport we discussed? Why shouldn’t we drink salt water? How do we regulate the amount of
water (and concentration of solutes) in our bodies?
Endocytosis Cells engulf large materials (nutrients, enemies)
with cell membrane.
Active Transport