High
concentration
How do particles
n
io
at
tr
en
nc
co
move IN and OUT
nt
ie
ad
gr
Low
concentration
of cells?
Part II
Some substances a cell may
need or may discard:
Water
Water
Glucose
Carbon dioxide
Oxygen
Ions
Ions
crossing a
LIVE
semi-permeable
IN
to
Is how living
organisms and
cells let
substances
OUT
OSMOSIS
ter
e
Wa ioxid
nd
o
b
r
s
Ca
Ion
from a
Is the
'
T
U
O
G
N
I
D
'SPREA
of
region of their HIGHER
concentration (+)
to a
when the
particles
are
water
can be
c a ll e d
ter
Wa se
co
Glu
en
yg
x
O
s
Ion
PARTICLES
membrane
is a
PASSIVE PROCESS
(no energy is needed)
region of their LOWER
concentration (-)
over time it
will reach
an
RIGHT
=
LEFT
EQUILIBRIUM
which means the
particles are
EVENLY SPREAD OUT
and the
NET MOVEMENT
of particles
is equal to
ZERO
Is how living
organisms and
cells let
substances
IN
OUT
to
LIVE
e
h
t
s
i
n
o
Diffusi
'
T
U
O
G
N
I
D
A
E
R
'SP
of
PARTICLES
from a
region of their HIGHER
concentration (+)
to a
region of their LOWER
concentration (-)
n
a
c
n
o
i
s
u
id f f a l l e d
c
be
OSMOSIS
when the
particles
are
water
crossing a
semi-permeable
membrane
diffusion over time
will reach an
RIGHT
=
LEFT
EQUILIBRIUM
which means the
particles are
EVENLY SPREAD OUT
and the
NET MOVEMENT
of particles
is equal to
ZERO
LET'S TALK ABOUT
NET MOVEMENT
Is a way of describing the
'OVERALL',
'FINAL',
'TOTAL'
movement taking place
MOVEMENT TO THE RIGHT
MOVEMENT TO THE LEFT
PARTICLE
SEMI-PERMEABLE MEMBRANE
In this case, the
'net' movement
is from left to
right
In this case, the 'net'
movement is equal to
ZERO.
The particles are
spread out evenly
CONCENTRATION
GRADIENTS
A concentration gradient is the unequal distribution of a
substance on two sides
HIGH
CONCENTRATION
OF
PARTICLES
LOW
CONCENTRATION
OF
PARTICLES
CONCENTRATION
GRADIENTS
Can be:
STEEP
SHALLOW
STEEP
CONCENTRATION
GRADIENT
SHALLOW
CONCENTRATION
GRADIENT
NO
CONCENTRATION
GRADIENT