This document discusses and classifies different types of molecule movement across cell membranes. It describes passive transport which includes diffusion, osmosis, and dialysis and requires no energy as molecules move from high to low concentration areas. Active transport is also discussed which requires energy for molecules to move against a concentration gradient or into the cell. Specific examples of osmosis and dialysis are provided.
5. • Diffusion
Molecules move from area of
higher concentration to area of
lower concentration.
6.
7. • Osmosis
Movement of water across the
selectively permeable
Membrane.
8. • In this
picture a
red blood
cell is put in
a glass of
distilled
water. Beca
use there is
a higher
concentrati
on of water
outside the
cell, water
enters the
cell by
OSMOSIS. I
n this case
too much
water
enters and
the cell
swells to
the point of
bursting
open.
