Transcript 7.3 Cell Boundaries

 Explain
the significance of the selectively
permeable membrane to the transport of
molecules.
 Predict the movement of molecules across a
selectively permeable membrane (diffusion,
osmosis, active transport) needed for a cell
to maintain homeostasis given
concentration gradients and different size
molecules.
 Explain how water is important to cells
(body temp., soluble environment, reactant
in chemical reaction, maintains turgidity).
 Identify
that water is important to cells.
 Explain how water is important to cells.
 Predict movement of molecules across a
selectively permeable membrane
needed to maintain homeostasis.
 Compare and contrast process used in
movement of molecules across a
semipermeable membrane, taking
energy use into consideration.
 Cell
Membrane – flexible barrier of cell
that regulates what enters and leaves the
cell.
 The cell membrane is “semipermeable”.
 Cell
Membrane – flexible barrier of cell
that regulates what enters and leaves the
cell.
 Cell Wall – protects cell and give cell
structure.
• Found only in plant cells.
 What
does permeable mean?
 What does semi permeable mean?
 In
a solution, particles move constantly.
 Diffusion – tendency of particles to move
from an area of high concentration to an
area of low concentration.
When do the particles of solute stop moving?
 When the concentration of solute is the
same throughout, and the system has
reached equilibrium (homeostasis).
 Water
diffuses across membranes more
easily than other substances.
 Osmosis – diffusion of water across semipermeable membrane.
Which of the following is an example of
diffusion?
a. A student sprays perfume and it moves
throughout the room.
b. Food coloring is added to a beaker of
water and slowly spreads during a
science experiment.
c. Both a and b are examples of diffusion.
d. None of the above are examples of
diffusion.
SMART Response Qu
To set the properties right click and select
SMART Response Question Object->Properties...
During diffusion, particles move from…
a. Area of high concentration to area of low
concentration.
b. Area of low concentration to area of high
concentration.
c. They don’t move…they’re just particles.
d. Areas where they will explode
SMART Response Qu
To set the properties right click and select
SMART Response Question Object->Properties...
 How
much energy does a cell use for
diffusion?
 Cell uses ________ energy for materials
to get into cell for DIFFUSION or
OSMOSIS.
 We
have more to
go for this section.
 We will begin a lab
later in the week.
 Vocabulary for
homework.
 Explain
the significance of the selectively
permeable membrane to the transport of
molecules.
 Predict the movement of molecules across a
selectively permeable membrane (diffusion,
osmosis, active transport) needed for a cell
to maintain homeostasis given
concentration gradients and different size
molecules.
 Explain how water is important to cells
(body temp., soluble environment, reactant
in chemical reaction, maintains turgidity).
 Identify
that water is important to cells.
 Explain how water is important to cells.
 Predict movement of molecules across a
selectively permeable membrane
needed to maintain homeostasis.
 Compare and contrast process used in
movement of molecules across a
semipermeable membrane, taking
energy use into consideration.
 What
is diffusion?
 Why does diffusion occur?
 What is osmosis?
Find out who is the oldest…hypertonic
Find out who is in the middle…hypotonic
Find out who is the youngest…isotonic
 Three
types of solutions:
1) Hypertonic – “above strength”
 Three
types of solutions:
1) Hypertonic – “above strength”
2) Hypotonic – “below strength”
3) Isotonic – “same strength”
 For
organisms to survive their cells
must balance the intake of water,
salts, sugars, and other molecules.
1)
2)
3)
4)
What is the difference between
diffusion and osmosis?
Which type of solution is considered
“same strength”.
Which type of solution is considered
“above strength”.
Which type of solution is considered
“below strength”.
 Don’t
forget about the vocabulary
worksheet from Monday.
 Chap. 7 Review
• Pg. 189 1-6 OMIT #5
• Pg. 197 20-23
 Wednesday/Thursday
we’ll do a case
study, finish notes (just a little left), and
talk about hand washing lab, build cell
transport foldable.
 Describe
the importance of selectively
permeable membrane to the transport of
molecules.
 Predict the movement of molecules
across a selectively permeable
membrane needed for a cell to maintain
homeostasis.
 Explain how water is important to cells.
1)
2)
3)
4)
What is the difference between
diffusion and osmosis?
Which type of solution is considered
“same strength”.
Which type of solution is considered
“above strength”.
Which type of solution is considered
“below strength”.
 What
if a cell is placed into a hypertonic
solution?
 What
if a cell is placed into a hypotonic
solution?
 What
if a cell is placed into a isotonic
solution?
So why don’t our cells burst open shrivel up?
Hypertonic
Isotonic
Hypotonic
 Some
molecules
seem to pass through
the cell membrane
more easily than they
should.
 Example: RBC’s
have
a glucose (sugar)
channel that allows
glucose to pass in
and out.
• Only glucose can pass
through the channel.
 Facilitated
Diffusion –
is the diffusion of
particles through
protein channels.

Hundreds of channels have
been found to allow only
one specific material
through.
• Carbohydrates and sugars
mostly
Hyper link
 Active
transport – transport of materials
that requires energy.
• Uses “pumps” that are found in the membrane.

The most common
pump is the
sodium (Na) –
potassium (K)
(salts) pump.
 Uses
energy to move molecules from low
to high concentration (against
concentration gradient).
Hyper link
PASSIVE TRANSPORT
1)
2)
3)
Diffusion
Osmosis
Facilitated
Diffusion
NO ENERGY
REQUIRED!!!
ACTIVE TRANSPORT
1)
Active
Transport
REQUIRES
ENERGY!!!
 Review
questions:
What do we call the diffusion of water?
How do large molecules diffuse into a cell when
they are too large to pass through the cell
membrane?
What is the difference between active transport
and passive transport?
What are three examples of passive transport?
 Have
a good weekend!