Transcript cell transport across membranes

CHAPTER 4 –
The Cell In Action
Section 1:
Exchange with the
Environment
TRANSPORT ACROSS THE
CELL MEMBRANE —
“LIPID BILAYER”
“FLUID MOSAIC MODEL”
PASSIVE TRANSPORT 
TAKING THE EASY ROAD
PASSIVE =
REQUIRES NO ENERGY
PASSIVE TRANSPORT =
DIFFUSION
DIFFUSION . . .
DIFUSION = OSMOSIS --WATER !!!
OSMOSIS . . .
1) Hypertonic --- salt solution
= shrink & shrivel
2) Isotonic --- tap water
= normal cell
3) Hypotonic --- distilled water
= swell & burst
“FACILITATED”
DIFFUSION
carrier proteins are
specific for the substances
they transport
ACTIVE TRANSPORT =
USES ENERGY
ACTIVE TRANSPORT . . .
time to eat & drink —
a cell engulfing a substance
is an example of active
transport
phagocytosis & pinocytosis
http://www.biology4kids.com/file
s/cell2_mitosis.html