Download SIGNIFICANT FIGURES

http://www.youtube.com/watch?v=aSfoB8Cmic&feature=relmfu
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elated
Cell Membrane
and its types of
Transport
About Cell Membranes
1.All cells have a cell
membrane
1. Functions:
a. Provides protection and
support for the cell
b. Controls what enters and
exits the cell to maintain an
internal balance
TEM picture of a
real cell
membrane.
LIPID BILAYER
About Cell Membranes (continued)
3.Structure of cell membrane
Lipid Bilayer is made up of
many small Phospholipids
a.The head is hydrophilic or
water loving
b. The tail is hydrophobic or
water fearing.
c.Proteins embedded in
membrane
Phospholipid
Lipid Bilayer
Heads of the
bilayer love
water.
Tails of the bilayer
hide from water.
Lipid Bilayer
Proteins
The Cell Membrane
About Cell Membranes (continued)
Cell Membrane
(aka Plasma Membrane)
• Controls the
movement of
molecules in and
out of the cell
• Selectively
Permeable
Selectively Permeable
• A membrane that allows only
certain things to pass through
Transport
Types of Transport
Passive
Active
DOESN’T REQUIRE ENERGY
REQUIRES ENERGY
Passive Transport
Passive
Particles passes through the cell from a
more crowded area to a less crowded
area.
Concentration
How much stuff there is
High
Concentration
Low
Concentration
Passive Transport
The passive movement
of material from an area
of high concentration to
an area of low
concentration
Passive Transport
Movement of
materials that DOES
NOT require energy
What happens to Kool-Aid crystals
over time???
Diffusion
The movement of PARTICLES through a selectively
permeable membrane from an area of high particle
concentration to low particle concentration
Solution
Solute = substance being dissolved
Solvent = dissolves another substance
Solution
Diffusion
Diffusion
Diffusion, which way will the
particles move?
Diffusion: does moving the molecules
in this direction require energy?
Types of Passive Transport
• Diffusion
• Osmosis
• Facilitated diffusion
• NONE OF THESE REQUIRE ENERGY
Types of Passive Transport
• Diffusion
• Osmosis
• Facilitated diffusion
• NONE OF THESE REQUIRE ENERGY
OSMOSIS
The movement of water through a
selectively permeable membrane
from an area of high water
concentration to low water
concentration
OSMOSIS
Purpose: so cells can maintain
BALANCE with their environment
Maintains Homeostasis
Concentration of Water: Which is
100%
higher? 75%
Water
50%
Water
and
50%
Sugar
Water
and
25%
Salt
50%
Water
and
50%
Salt
75%
Water
and
25%
Salt
100%
Water
Hypotonic
• Concentration of water INSIDE a cell is
SMALLER than concentration of water
outside a cell
• Which direction will water move?
100%
Water
50%
Water
and
50%
Sugar
100%
Water
50%
Water
and 50%
Sugar
Will the cell increase or decrease in
size?
Hypertonic
• Concentration of water INSIDE a cell is
LARGER than concentration of water
outside a cell
• Which direction will water move?
Hypertonic
75%
Water
and
25%
Salt
100%
Water
Will the cell increase or decrease in
size?
Isotonic
• Concentration of
water INSIDE a cell
is the SAME as
water outside a cell.
• What direction will
water flow?
Isotonic
50%
Water
and
50%
Salt
50%
Water
and
50%
Sugar
Will the cell increase or decrease in
size?
1.Hyp0tonic, 2.Hypertonic, or
3.Isotonic?
100% Hypotonic
100%
Water
Water
50%
Water
and
50%
Sugar
100%
Water
50%
Water
and
50%
Salt
Isotonic
75%
Water
and
25%
Salt
Hypertonic
1.Hypotonic, 2.Hypertonic, or
3.Isotonic?
Isotonic
50%
Water
50%
Sugar
50%
Water
and
50%
Sugar
75%
Water
and
25%
Salt
Hypertonic
100%
Water
Water flow in or out?
100%
Water
50%
Water
and
50%
Sugar
100%
Water
100%
Water
50%
Water
and
50%
Salt
75%
Water
and
25%
Salt
Water flow in or out?
50%
Water
50%
Sugar
50%
Water
and
50%
Sugar
75%
Water
and
25%
Salt
100%
Water
Osmosis
80% water
30% salt
95% water
5% salt
Osmosis
80% water
30% salt
95% water
5% salt
Osmosis
95% water
5% salt
75% water
20% salt
Osmosis
95% water
5% salt
75% water
20% salt
Types of Passive Transport
• Diffusion
• Osmosis
• Facilitated Diffusion
• NONE OF THESE REQUIRE ENERGY
Facilitated Diffusion
• Why facilitated diffusion?
• When materials cannot move through the
cell membrane, it gets help from a protein
channel.
• But it is still a type of passive transport
because?
Facilitated diffusion
Channel Proteins allow specific molecules through.
NO ENERGY REQUIRED!
High Concentration
Low concentration
through a protein channel
Facilitated Diffusion
Facilitated Diffusion: still move
from high to low
Facilitated Diffusion: still move
from high to low
What are the 3 types of Passive
transport??
3 types of passive transport
• Diffusion
• Osmosis
• Facilitated Diffusion
Active Transport
Active
REQUIRES ENERGY
Active Transport
Movement of materials
from low concentration to
high concentration using a
protein carrier that
requires energy
Active Transport
Requires ENERGY to happen– the cell has to
work for it.
Carrier Proteins make it happen.
Active Transport
Active transport: Which way will
the molecules move?
Does moving the molecules in this
direction require energy?
Active
Transport
Active
Transport
Types of Active Transport
• Endocytosis
• Exocytosis
Endocytosis
Process of bringing
particles into a cell using
extensions of the cellular
membrane
To determine endocytosis
1. Particle starts OUTSIDE the cell.
2. Cell membrane wraps around particle.
3. Particles end INSIDE the cell.
• FROM THE OUTSIDE TO THE INSIDE !!
Exocytosis
Process of moving particles out of a
cell by fusing a vesicle to the cell
membrane
(how wastes are excreted from cells)
To determine exocytosis
1. Particle starts INSIDE the cell, in a vesicle.
2. Vesicle fuses with cell membrane.
3. Particles are released and end up
OUTSIDE the cell.
FROM THE INSIDE TO THE OUTSIDE
Endocytosis vs.
Exocytosis
Check for understanding
• Active transport moves molecules from an
area of ______________ concentration to
__________ concentration
• Passive transport moves molecules from an
area of ______________ concentration to
__________ concentration
How do you determine Active or
Passive?
1. You count the number of particles inside,
then outside.
2. Label MORE or LESS on both sides.
3. Passive – the arrow goes from more to less
Active- the arrow goes from less to more.
Active or Passive?
Active or Passive?
Diffusion is the movement of particles from
________ concentration to __________
concentration across the membrane.
Osmosis is the movement of __________
across the membrane from high
concentration to low concentration.
Osmosis
95% water
5% salt
75% water
20% salt
Facilitated Diffusion
The movement of molecules from ________
concentration to ________ concentration
with the help of a _______________.
Does this require energy?
What are the three types of
passive transport?
Passive Transport
• Diffusion
• Osmosis
• Facilitated diffusion
Endocytosis: particles _______ the cell when
the cell membrane wraps around the particle
and pushes it in.
A.
B.