Cell Transport FA
Learning Goal:
Predict movement of molecules through the cell membrane given
environmental or cell conditions and describe its affect on a cell.
1
Tutorials on cell transport
Passive transport
Tutorial on diffusion, facilitated diffusion, and active transport
http://www.sumanasinc.com/webcontent/animations/content/diffusion.html
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_facilitated_diffusion
_works.html
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.ht
ml
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_the_sodium_potas
sium_pump_works.html
http://highered.mcgrawhill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120068/bio0
2
2.swf::Endocytosis%20and%20Exocytosis
ut
e
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it s
.. .
it s
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DO
W
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N.
..
ut
e
DO
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rt
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an
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3
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at
er
D.
UP
C.
rt
of
w
B.
Transport of water
DOWN its concentration
gradient
Transport of solute
DOWN its concentration
gradient
Transport of solute UP its
concentration gradient
Transport of water UP its
concentration gradient
an
sp
o
A.
What is diffusion?
Tr
1
2
Pick the following statement that best describes
facilitated diffusion.
4
M
ov
in
e.
..
gD
OW
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so
lu
of
ov
em
en
t
it s
te
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nc
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s..
.
ea
to
M
en
er
gy
Us
in
g
M
ov
em
en
t
of
w
m
at
er
D.
ov
C.
25% 25% 25% 25%
it.
..
B.
Movement of water UP its
concentration gradient
Using energy to move a solute
DOWN its concentration
gradient
Movement of solute DOWN its
concentration gradient through a
protein channel
Moving DOWN its
concentration gradient by
passing through spaces between
phospholipid molecules
UP
A.
3. How is active transport different from
passive transport?
Active transport pumps solutes
DOWN their concentration
gradient
Passive transport does NOT
require cell energy, but active
transport DOES require cell
energy
Passive transport pumps water
UP its concentration gradient
Active transport does NOT
require cell energy, but passive
transport DOES require cell
energy
ns
po
rt
tra
et
Pa
ss
iv
do
es
um
ps
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oe
rt
d
pu
m
ps
ra
ns
po
et
ns
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Pa
ss
iv
tra
Ac
t iv
e
5
NO
...
25% 25% 25% 25%
s. .
.
D.
rt
p
C.
Ac
t iv
e
B.
ra
ns
po
A.
4. True or False.
Large polar substances & ions (like Ca2+)
cannot move through a cell’s plasma
membrane unless they move through a
carrier protein because the interior of the
membrane is nonpolar.
se
50%
Fa
l
6
50%
ue
B.
True
False
Tr
A.
5 When the concentration of solute is lower in
the solution bathing a cell than inside the cell’s
cytoplasm, environment the solution is _______.
0%
0%
to
ni
c
0%
Aq
ua
Hy
pe
rt
7
on
i
c
0%
ic
D.
Hy
po
to
n
C.
c
B.
Hypertonic
Isotonic
Hypotonic
Aquatonic
Iso
to
ni
A.
Explanation for # 5
Why are solute &
water concentrations INVERSELY related?
Assume the volume of solution
surrounding the cell & the volume
of the cytoplasm are equal. Count
water molecules outside the cell_____ & &
inside the cell_____.
Solute takes up space, leaving less
room for water molecules!
If you consider movement of water, is the
direction of movement passive—from higher
to lower water concentration? ____
8
6 When the concentration of the solute is the
same on the outside of the cell as it is inside the
cell the solution is
9
0%
c
0%
to
ni
c
0%
Aq
ua
Hy
pe
rt
on
i
c
0%
on
i
D.
Hy
pe
rt
C.
c
B.
Hypertonic
Isotonic
Hypertonic
Aquatonic
Iso
to
ni
A.


Iso- means equal (like in an iso-lateral
triangle, two sides have equal length)
Is the concentration of water inside
the cytoplasm the same as the
concentration of water outside the
cell when solute concentrations are
equal in both? Yes!
Assume the total volume of the solution
outside the cell is equal to that of the
cytoplasm. Count the solute
molecules inside the cell_____
outside the cell____. Count the
number of water molecules inside the
cell_____ Outside the cell_____
10
7 In which direction will the net
movement of water be in the following
example?
10 %
0%
in
..
ce
ll
eq
ua
l
11
0%
Ou
to
ft
he
In
to
th
e
ce
ll
0%
ov
e
C.
20%
solute
80%
H2O
m
B.
Into the cell
Out of the cell
equal amounts move
into and out of the
cell
90% H2O
am
ou
nt
s
A.
solute
8 What type of solution is in the
environment of the cell?
0%
c
0%
to
ni
c
0%
Aq
ua
12
Hy
po
to
n
ic
0%
on
i
D.
Hy
pe
rt
C.
10%
solute
90%
H2O
c
B.
Hypotonic
Isotonic
Hypertonic
Aquatonic
70%
H2O
Iso
to
ni
A.
30 %
solute
13
33%
33%
c
to
ni
Hy
po
to
n
ic
C.
33%
Hy
pe
r
B.
Hypotonic
Isotonic
Hypertonic
20%
90
solute
80%
H2O
c
A.
25%
solute
Iso
to
ni
9 What is the type of
environment for this cell?
75 %
water
33%
33%
14
Eq
ua
33%
...
&
o
nt
en
ti
lm
ov
em
In
to
th
e
ce
ll
C.
10%
solute
90%
H2O
l
B.
Into the cell
Out of the cell
Equal movement
into & out of the
cell
70%
H2O
ce
l
A.
30 %
solute
Ou
to
ft
he
10. What will be the net
direction of water
movement?
11 What type of environment is shown?
0%
0%
to
ni
c
0%
Aq
ua
15
Hy
pe
rt
on
i
c
0%
ic
D.
Hy
po
to
n
C.
20%
solute
80%
H2O
c
B.
Hypertonic
Isotonic
Hypotonic
Aquatonic
75%
H2O
Iso
to
ni
A.
25 %
solute
60% H2O
60%
H2O
0%
aq
ua
to
n
ic
c
0%
to
ni
ni
c
0%
hy
po
to
16
hy
pe
rto
ni
c
0%
iso
Extra
The cytoplasm in
the cell is
A. hypertonic
B. hypotonic
C. isotonic
D. aquatonic
40%
solute
60%
solute
0%
0%
aq
ua
to
n
ic
c
ic
0%
Hy
po
to
n
17
Hy
pe
rt
on
i
c
0%
Iso
to
ni
Extra
What type solution is
the cell in?
A. Hypertonic
B. Hypotonic
C. Isotonic
D. aquatonic
12 What process explains the passive movement
of water across a semi-permeable membrane?
0%
Di
ffu
sio
ed
ta
t
Ac
t iv
e
18
0%
n
n
0%
Di
ffu
sio
Os
m
os
is
0%
ili
D.
ns
po
rt
C.
Fa
c
B.
Osmosis
Diffusion
Active transport
Facilitated Diffusion
tra
A.
13 Red blood cells & other animal cells which don’t have a
cell wall burst if they are in what type of a solution? Small
dots are water molecules; larger dots are solute.
?
?
19
Hy
pe
rt
on
i
c
0%
?
0%
0%
0%
to
ni
c
?
Aq
ua
?
?
ic
D.
?
Hy
po
to
n
C.
?
c
B.
Hypertonic
Isotonic
Hypotonic
Aquatonic
Iso
to
ni
A.
Lower water and higher
solute inside cell versus
higher water & lower solute
outside—water moves down
its concentration gradient
(high to low)
Equal water and solute
concentration in/out; the same
amount of water enters &
exits because the cell is
already at concentration
equilibrium.
20
Higher water and less solute
inside versus lower water &
higher solute outside—water
moves down its
concentration gradient (high
to low)
Why don’t plant cells burst after lots of
rain makes the soil hypotonic compared
to the cell cytoplasm?
...
em
w
m
el
l
ha
v
ec
ha
v
el
ls
el
ls
tc
Pl
an
0%
el
l
ec
qu
ap
ea
ha
v
el
ls
tc
Pl
an
21
0%
all
s
0%
or
i..
.
C.
tc
B.
Plant cells have
aquaporin channels
Plant cells have cell
walls
Plant cells have cell
membranes
Pl
an
A.

The cell wall of plants presses inwards so that the cell
doesn’t take on enough water to burst.
22
Why do plants die by plasmolysis
(plasma membrane breaking) near
salted highways and sidewalks?
50%
mu
so
y ta
Th
ey
re
le a
se
st
b
23
kin
g in
...
ch
wa
...
50%
ey
bu
r
B.
They burst by taking
in too much water
from hypotonic soil
They release so
much water to the
hypertonic soil that
their membranes
shrink & break
Th
A.
If the cell loses most of the water stored
in its large central vacuole, so little
pressure is exerted on the cell
membrane that it collapses inwards.
This tears the cell membrane since it
was attached to the cell wall, killing the
cell. Plasmo- plasma membrane
lysis - break up
24