Download Passive Transport

Passive
Transport
Passive Transport
● Movement of molecules across a membrane
● Uses no energy
● Moves down the concentration gradient
(high to low concentration)
High
Low
Equilibrium
Passive Transport
There are 3 types of passive transport
● Diffusion
● Facilitated diffusion
● Osmosis
Diffusion
● The movement of molecules in fluid or gas
until molecules are in equilibrium (evenly
spread out)
● Examples: Dye in water, smells
● In cells, small lipids, CO2, & O2 diffuse
through the membrane
Diffusion
Facilitated Diffusion
● Diffusion across a
membrane with
transport proteins
● Proteins only allow
a specific particle
through
Osmosis
● The movement of water
across a semipermeable
membrane
● The more particles in a
solution means less water,
causing a movement of
water.
3 Solutions of Osmosis
Isotonic
● Equal concentration of
particles and water in & out
of the cell
● Equal water movement in
and out
● Cell stays the same size
3 Solutions of Osmosis
Hypertonic
● Solution has more
particles than inside
the cell
● Water leaves the
cell
● Cell shrinks
3 Solutions of Osmosis
Hypotonic
● Solution has more water
than inside the cell
● Water enters the cell
● Cell expands