Transcript Cell Transport

Cell Membrane
Transport Notes
JUNE 2, 2016
I.) Types of Cell Membrane Transport
 There are 2 types of cell membrane transport:
A. Passive Transport
Things flow from
High to low
1.
B. Active Transport
Things flow from
Low to high
1.
Passive & Active Transport
II.) Passive Transport
A. Diffusion
1.


Definition: The movement of particles from areas
of high concentration to low concentration
http://www.indiana.edu/~phys215/lecture/lecnotes/diff.html
http://www.biosci.ohiou.edu/introbioslab/Bios170/diffusion/Diffusion.html
2. Equilibrium
a. Continuous movement of particles, but no change
in concentration
b. When is equilibrium reached when discussing cell
membrane transport?

When the concentrations of particles are the same on both
sides
3. Facilitated Diffusion
a. Particles flow from high concentration to low
concentration but this time they need the help of
proteins to get through the cell membrane.
Facilitated diffusion
Passive transport (cont.)
B. Osmosis
1.
2.
3.
The diffusion of water across a selectively permeable
membrane
Important in maintaining cell homeostasis
Water flows to side of membrane where the water
concentration is lower until equilibrium is reached
Osmosis (cont.)
4. Osmosis is controlled by the amount of solutes on
either side of a membrane
Remember, this is important, Osmosis deals
with what?
Th
e
to
...
m
ov
e
m
en
to
...
m
en
m
Th
e
m
e
Th
0%
ov
e
m
en
to
...
0%
ov
e
m
en
to
...
5%
ov
e
4.
m
3.
95%
e
2.
The movement of
particles
The movement of
glucose
The movement of
water
The movement of
lipids
Th
1.
Cell Membrane Transport
Notes (cont.)
JUNE 2, 2016
I.) Types of Cell Membrane Transport
 There are 2 types of cell membrane transport:
A. Passive Transport
Things flow from
High to low
1.
B. Active Transport
Things flow from
Low to high
1.
II.) Osmosis – Types of Solutions
A. When dealing with osmosis, water can either move
into the cell or out of it.
1.
The solute cannot move to equal out the solution so the water
has to.
90%
What are the
concentrations?
2.
40%
We describe the solutions that cells are in as either hypotonic, isotonic,
or hypertonic.
B. Isotonic Solution
1.
Isotonic solution – Concentration of solute is the
same in the cell and the solution cell is in
 Give me an example of an isotonic solution that some
of you use everyday
Isotonic solution
C. Hypotonic Solution
Hypotonic Solution – Concentration of solute is
lower in the solution than in the cell.
1.
2. Where is water going to move in order to reach
equilibrium (Equal concentrations)?

Inside the cell
Hypotonic solutions (cont.)
3. Since water moves into the cell the cell can explode
Plant & animal cells in a hypotonic
solution
D. Hypertonic Solution
Hypertonic solution – concentration of solute is
higher in the solution than in the cell.
1.
2. Where is water going to move in order to reach
equilibrium (Equal concentrations)?

Outside the cell
Hypertonic solutions (cont.)
3. Since water moves out of the cell, the cell will shrink
Plant & animals cells in a Hypertonic
Solution
Osmosis
 http://www2.nl.edu/jste/osmosis.htm
The following diagram demonstrates what type of
solution?
= solute
60%
25%
ic
er
to
n
yp
H
Is
c
ot
on
i
3.
yp
2.
Hypotonic
Isotonic
Hypertonic
H
1.
ot
on
ic
15%
In the following diagram which way is water
going to move?
= solute
50%
40%
O
2
1
ot
h
B
ut
si
de
of
an
d
th
e
l..
.
ce
th
e
3.
si
de
2.
Inside the cell
Outside of the cell
Both 1 and 2
In
1.
...
10%
The following diagram demonstrates what
type of solution?
= solute
85%
H
yp
er
to
n
ic
ot
on
ic
Is
c
ot
on
i
3.
0%
yp
2.
15%
Hypotonic
Isotonic
Hypertonic
H
1.
In the following diagram which way is water
going to move?
= solute
95%
2
...
O
1
ot
h
B
ut
si
de
of
an
d
th
e
l..
.
ce
th
e
3.
5%
0%
si
de
2.
Inside the cell
Outside of the cell
Both 1 and 2
In
1.
III.) Active Transport
A. Definition: Molecules move from low concentration
to high concentration
Requires energy….why?
1.

Going against the natural concentration
gradient
B. Other membrane transport activities
that require energy
1.
Endocytosis: Engulfing of large particles or liquids
from outside the cell
Other membrane transport activities that
require energy (cont.)
2. Exocytosis: Release of large particles or liquids from
inside the cell
Inside
the cell
Outside
the cell
This diagram is an example of what
membrane transport?
85%
yt
os
is
5%
oc
Ex
En
do
cy
d
to
s
is
di
...
5%
at
e
ci
lit
Fa
4.
5%
si
on
3.
iff
u
2.
Diffusion
Facilitated diffusion
Endocytosis
Exocytosis
D
1.
This diagram is an example of what
membrane transport?
100%
yt
os
is
0%
oc
Ex
En
do
cy
d
to
s
is
di
...
0%
at
e
ci
lit
Fa
4.
0%
si
on
3.
iff
u
2.
Diffusion
Facilitated diffusion
Endocytosis
Exocytosis
D
1.