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Homeostasis and
Transport
Concentration
 The amount of solute in a solution.
 Often measured as a percentage.
 Deciding factor as to where particles
move.
Passive Transport
 Movement of particles that does not
require energy.
 Diffusion
 Osmosis
 Facilitated Transport
Diffusion
 When particles move from an area of
high concentration to an area of low
concentration.
 Seeks to reach equilibrium

Equilibrium: when the concentration of
solute is the same through out the system.
 Even when equilibrium is reached,
particles will continue to move (even
exchange)
Diffusion, cont.
Osmosis
 The diffusion of water through a
selectively permeable membrane.
 For example, sugar molecules can’t fit
through the cell membrane, therefore,
the water moves instead.
Osmosis
 Ex: Same concentrations
Osmosis
 Ex: salt water plant in freshwater
Osmosis
 Ex: freshwater plant in saltwater
Facilitated Diffusion
 Occurs when proteins in the cell
membrane move molecules across the
membrane.
 Helps to “facilitate” or help the
movement of sugar molecules.
 http://highered.mcgrawhill.com/sites/0072495855/student_view
0/chapter2/animation__how_facilitated_d
iffusion_works.html