Transcript The Cell Membrane

Chapter 3
“Cell Processes”
Bellwork 1/3

Copy and answer in complete sentences:

1) The Cell membrane is said to be “selectively
permeable”. What does this mean?

2) Perfume is sprayed from a small bottle. The
smell lingers but eventually disappears. Why do
YOU think this happens?
Learning Target

I can….

1)Explain the
difference between
diffusion and osmosis.

2)Predict the
movement of particles
into and out of a cell.
Section 3.2
“MOVING CELLULAR
MATERIAL”
”All” cells must obtain and use
materials for energy”…..
Copyright Cmassengale
ATP
Stands for “Adenosine triphosphate”
Also known as “energy”.
It’s the fuel for cells.
How do cells get energy?...........
Cells break down sugar and fats to help
release energy.
This energy is transferred to ATP which
the cell can use.
The energy must be transferred to ATP
before the cells can use it.
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Quickcheck:

Which organelle in a cell is
responsible for the production of
ATP?

MITOCHONDRIA
Copyright Cmassengale
Remember me:
“The Cell Membrane”
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Cell Membrane
The cell membrane is
made of 2 layers of
phospholipids called the
lipid bilayer
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Close that window!!!
There are many reasons we open and shut
the windows in our house.
 Do you want to let all of the bugs and leaves
in?
 A window screen provides the protection to
keep unwanted things outside . But it also
allows some things to pass into and out of
the room like air, unpleasant odors, or
smoke.
 How does the cell membrane carry out
similar functions to that of a window screen?

The cell membrane



A cell membrane, like a screen, will let
some things through more easily than
others.
Ex: Air gets through a screen, but insects are kept out.
A cell’s membrane is “selectively
permeable”. In other words it allows
some things to enter or leave the cell
while keeping other things outside or
inside of the cell.
Solubility
 Materials
that
are soluble in
lipids can pass
through the
cell membrane
easily
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What determines how particles move in
and out of the cell?
Which way particles
moves depends on the
 a) size of the molecule
or particle,
 B) the path taken
through the
membrane,
c) whether or not
energy is used.

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Semipermeable Membrane
Small molecules move through the cell
membrane very easily.
e.g. (O2, CO2, H2O)
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Semipermeable Membrane
Molecules larger than water (such as
proteins) do not move through the membrane
on their own.
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Types of Transport
Across Cell
Membranes
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Moving things “without
energy”
The movement of substances through
the cell membrane “without using
energy” is called passive transport.
 The cell membrane can move things into
and out of the cell without using energy
either by:
 Simple Diffusion
 Osmosis
 Facilitated diffusion

Diffusion
Simple Diffusion
 Doesn’t require energy
 Moves materials from
high to low concentration
 Example: Oxygen
and/or water diffusing
into a cell and carbon
dioxide diffusing out.
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Simple Diffusion
In other words
 Molecules move

from
crowded
to less
crowded areas
of concentration.
 This can occur in
solids, liquids, and
gases.
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Diffusion “in action”…..

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You might smell perfume when you sit near or walk
past someone wearing it. This is because the perfume
molecules are randomly moving throughout the air .
The molecules are going from an areas that is
crowded (such as inside the bottle) to a less crowded
area (such as the air itself).
There’s more space for the molecules to spread out
and move in the air.
Diffusion stops once there is an equal number of
molecules in both areas.
The molecules are in equilibrium.
DIFFUSION
Diffusion is a
PASSIVE process
which means no
energy is used to
make the
molecules move,
they have a
natural KINETIC
ENERGY
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Diffusion of Liquids
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Diffusion through a
Membrane
Cell membrane
Solute moves DOWN concentration gradient (HIGH to
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LOW)
Let’s take a look!!

Animation of How Diffusion Works
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Osmosis
Diffusion of
“water” across a
membrane
 Moves from HIGH
water potential
(low solute) to
LOW water
potential (high
solute)

Diffusion across a membrane
sem-i-permeable
membrane
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Click on Picture for Animation
Practice 1….
10% NaCL
90% H2O
ENVIRONMENT
CELL
10% NaCL
90% H2O
No net
movement
What is the direction of water movement?
equilibrium
The cell is at _______________.
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Practice:Sample 2
10% NaCL
90% H2O
CELL
20% NaCL
80% H2O
What is the direction of water movement?
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Practice: sample 3
15% NaCL
85% H2O
ENVIRONMENT
CELL
5% NaCL
95% H2O
What is the direction of water movement?
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Practice 4
40% NaCl ENVIRONMENT
60% H2O
CELL
20% NaCl
80% H2O
What is the direction of salt (NaCl)
Practice 5
20% NaCl ENVIRONMENT
80% H2O
CELL
90% NaCl
10% H2O
What is the direction of salt (NaCl)
Let’s review and discuss…….
Quick check:
#3) Which of these is selectively
permeable?
A) door
c) wall
B) window screen
d) mirror
#12) During the process of diffusion:

a) a cell surrounds and absorbs large particles

b) particles move from areas of lower

concentration to higher concentration

c) a cell surrounds and gets rid of large

particles

d) particles move from areas of higher

concentration to lower concentration

#14) When water diffuses into or

out of a cell, it is called:

a) exocytosis c) endocytosis

b) osmosis
d) flooding

A simple rule to remember is: salt sucks
Salt is a solute. When it is concentrated inside or
outside the cell, it will draw the water in its
direction.
This is also why you get thirsty after eating
something salty!
“container”
30% salt
70%
water
100%
water
0% salt
“Flower”
The addition of
salt in the
container lowers
the concentration
of water.
The water
concentration is
higher in the cells
of the flower.
What happens when you put salt on
a snail?
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


They will shrivel up!!!
Why?
The bodies of snails and slugs contain much
water in them. Due to the process of osmosis,
in the scenario of salt and snails, the snails act
as the area with high water concentration. On
the other hand, the salt that you add to the
snails has a low water concentration.
The snails really do not melt when we add
salt. They dry up because too much water in
their bodies is sucked out of them and into the
salt. The poor snails shrivel up and die as a
result.
What do you think?
A fish that is accustomed to living in salt water is
placed in fresh water. What do you predict might
happen to the cells of the fish?
A. They might shrink up and cause the fish to die.
B. They would become healthier because the water
is so fresh.
C. They might swell and burst and cause the fish to
die.
What do you think?
A fish that is accustomed to living in salt water is
placed in fresh water. What do you predict might
happen to the cells of the fish?
A. They might shrink up and cause the fish to die.
B. They would become healthier because the water
is so fresh.
C. They might swell and burst and cause the
fish to die.
The process of osmosis would explain the net
movement of water into a cell if the percentage of
A.water was 90% inside the cell and 95% outside the
cell
B.water was 95% inside the cell and 90% outside the
cell
C.protein was 30% inside the cell and 35% outside the
cell
D.water and protein was equal inside and outside the
cell
The process of osmosis would explain the net
movement of water into a cell if the percentage of
A.water was 90% inside the cell and 95%
outside the cell
B.water was 95% inside the cell and 90% outside the
cell
C.protein was 30% inside the cell and 35% outside the
cell
D.water and protein was equal inside and outside the
cell
Activity (Diffusion Demo)
ISN. Page ?
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Pay close attention to the
demonstration I am about to show
you…Answer the questions as we go
along.




*
once you get to the data
table on the back of your
sheet. We answer the rest tomorrow!!
Copyright Cmassengale
Homework………………………….ISN (p. ?)
“Diffusion Practice Questions”:
Copy each question below and answer them in a complete
sentence:
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
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Describe what is happening in the cell when:
1) At the grocery store, they spray water on the
produce. Why?
2) Fred puts the salty water from his ice cream
maker on the grass growing in the cracks of his
driveway.
3) You’re having friends over for dinner and the
lettuce for the salad you were going to prepare is
limp and wilty. Why?
Copyright Cmassengale
Homework………………………….ISN (p. ?)
“Answers to Diffusion Practice Questions”:
Describe what is happening in the cell when:
 1) At the grocery store, they spray water on the
produce. Why?
The water will be “absorbed” by the produce.
 100% water outside the plant’s cell will draw the
water “into” the plant cell (which may not have any
water in it at all)…..Also the plant cell (vacuoles)
may consist of a variety of fluids which may
include water…so the concentration is lower inside
anyway).

Copyright Cmassengale
Homework………………………….ISN (p. 158)
Answers to:“Diffusion Practice Questions”:

2) Fred puts the salty water from his ice cream
maker on the grass growing in the cracks of his
driveway.

Because there is a higher concentration of salt in
the salt water and no salt in the cells of the grass,
the salt solution will absorb the water from the
plant eventually killing it. This will get rid of Fred’s
grass problem.
Copyright Cmassengale
Homework………………………….ISN (p. 158)
“Answers to…Diffusion Practice Questions”:



Describe what is happening in the cell when:
3) You’re having friends over for dinner and the
lettuce for the salad you were going to prepare is
limp and wilty. Why?
The water will be absorbed “out of” the plant. AGAIN
THERE IS A HIGHER CONCENTRATION OF WATER IN
THE plant (100%)…and 0% outside of the plant so it will
draw it out of the plant.
Copyright Cmassengale
Activity
Complete the worksheet on “Diffusion
In Cells”. Paste this on page ? in your
ISN.
Copyright Cmassengale
“Facilitated diffusion”
*What does the word facilitate mean?
Doesn’t require energy
but still needs help! It
uses transport proteins
to provide “doorways” to
help move material from
high to low concentration
Examples: Glucose (sugar)
or amino acids (--a chain
of proteins) moving from
blood into a cell.
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Facilitated Diffusion
Molecules will spontaneously move through the
pores of the cell membrane with the help of
“Channel Proteins” that provide a “doorway”
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Facilitated Diffusion
Carrier proteins
do not extend
through the
membrane.
 They bond and
drag molecules
through the lipid
bilayer and
release them on
the opposite side.

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Active Transport
DOES Require energy
(ATP)
Moves materials from
LOW to HIGH
concentration. It goes
AGAINST the
concentration gradient
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Types of Active Transport
Some transport
proteins require energy
to do work
These “Protein
Pumps” change
shape to move
molecules: this
requires energy!
Sodium
Potassium
Pumps
(Active
Transport
using
proteins)
2 Ways to Move the “Big Stuff”
1) Large molecules move materials into the cell
by endocytosis.
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Endocytosis
It takes in dissolved molecules as a
“vesicle”
is being formed.
.
This is sometimes called “Cell eating”.
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Now Watch it Work! 
Endocytosis: taking bulky
material into a cell
• Uses energy
• Cell membrane surrounds
the food particle
• Called “cell eating”
because it forms a food
vacuole & digests food
• This is how white blood
cells eat bacteria!
Another Way to Move the “Big Stuff”
2) Exocytosis-
moving large
things out.
Large molecules are moved out of the cell by vesicles
that fuse with the cell membrane through exocytosis.
Exocytosis is how many hormones are secreted and how
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nerve cells communicate with one another.
Now Watch it work! 
Exocytosis: a process that
forces material out of
cell “in bulk”
• Membrane surrounds the
material and fuses with the
cell membrane
• Cell changes shape –
requires energy
• EX: Hormones or
wastes released from
cell
Endocytosis &
Exocytosis
animations
Animation of Types of
Active Transport
Endocytosis &
Exocytosis
animations
Active vs Passive transport

Is similar to riding a bike…It takes no
energy to ride the bike and carry
things downhill… (passive transport)

But it takes energy to ride a bike to
carry you uphill…(active transport)
Types of Cellular Transport
•Animations of Active
Transport & Passive
Transport
•
Weeee!!
!
Passive Transport
cell doesn’t use energy
1. Diffusion
2. Facilitated Diffusion
3. Osmosis
•
high
low
Active Transport
cell does use energy
1. Protein Pumps
2. Endocytosis
3. Exocytosis
This is
gonna be
hard work!!
high
low
BW Copy &
complete each
statement
1. What is the “fuel” for
all cells_____
2. Diffusion is the movement of particles
from ________ areas of concentration to
areas of __________ concentration.
3. Osmosis is a specialized type of diffusion
that involves ___________.
BrainPop on “active transport”
 active
transport
Assignment:
 After the BrainPop, complete the
handout “Into and Out of
Cells”…..put this on page 135 in
your ISN.
***Reminder:
 Quiz & Test next week 
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Fill in your columns with the phrases
below…some may be used more than once








Particles move through protein doorways
Particles move through cell membrane between
phospholipid molecules
Sugar or amino acids
Requires ATP
Particles move from an area of high concentration
to an area of low concentration
Does not require ATP
Water
Particles move from an area of low concentration to
an area of high concentration
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Bellwork
Draw the illustration & answer the questions
25% NaCl Outside Environment
65% H2O
CELL
35% NaCl
35% H2O
What is the direction of water movement?
What is the direction of the salt (NaCl)?
Explain your answers.
How did you do?
25% NaCl
65% H2O
Outside Environment
CELL
35% NaCl
35% H2O
What is the direction of water movement? Into the cell
What is the direction of the salt (NaCl)? Out of the cell
Explain your answer. Molecules move from areas of high
concentration to lower concentration
“How did you do on your exit
ticket ???”
Examine how the particles in each
example are moving and tell if the
process is osmosis, equilibrium, simple
diffusion, facilitated diffusion, or
active transport.
1.
2.
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Examine how the particles in each example are
moving and tell if the process is osmosis, equilibrium,
simple diffusion, facilitated diffusion, or active
transport.
3.
4.
Examine how the particles in each example are moving and
tell if the process is osmosis, equilibrium, simple
diffusion, facilitated diffusion, or active transport.
5.
Quickcheck:
Turn to page 135 in your ISN:
 Let’s check and review your answers to the
“into and out of cells” worksheet………

Get out a “red” pen or pencil and go back to
your “Ch. pre-assessment” on page 128.
See if you can Correct your answers to
questions 5-13. We will go over these!
…..Bell work:

List three facts you know about photosynthesis.
1) ____________
2) ____________
3) ____________

What is the chemical formula for photosynthesis?.
(write it out in a chemical equation!)
SECTION 3.3
“CELL ENERGY”
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Here are your Target Goals:
I can:
 ---describe
photosynthesis and
cellular respiration.

Corny Joke of the Day!!!

Q: How do cells communicate with one
another?
A: by “Cell”ular Phone!!!!

(Ha! Ha! Ha!)

It Begins with Sunlight!
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The sun’s energy!
Mostly all the earth’s
energy comes from
the sun.
Plants and some other
types of organisms
that contain
chlorophyll are able to
use the light energy
from the sun to
produce food.
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Photosynthesis

Involves the Use Of Light Energy to
convert Water (H20) and Carbon Dioxide
(CO2) into Oxygen (O2) and High Energy
Sugar(C6H12O6 or Glucose).
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The Photosynthesis
Equation
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Pigments
• In addition to water,
carbon dioxide, and light
energy, photosynthesis
requires “pigments”.
• Chlorophyll is the primary
pigment that traps the
sunlight and it is found inside
the organelle called
chloroplasts.
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All organisms need energy….
Animals and other organisms “can not ” make their
own food.
Instead they consume plants and other organisms as
their source of food.
The food you eat has to be broken down so that the
energy it contains can be converted into a form your
cells can use.
Do you remember what that form of energy is?
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How do we get our
energy??..
 organisms
“break down food” and
release energy….
through a process called
Cellular
respiration --- it
involves the use of
oxygen….. It is also called
“aerobic respiration”.
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Chemical Equation for
Cellular Respiration…

Study this and tell me…
How is it similar to the equation for
photosynthesis?
Cellular respiration
In most Eukaryotes…

Cellular
respiration takes
place in the
mitochondria of
plants and animals.
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Releasing Energy From ATP
Energy is released in your body in the
form of ATP. It is constantly being
used and remade by cells.
 ATP provides all of the energy for
cell activities.


Most of the energy “released” is in the
form of heat (which your body uses to
maintain body temperature).
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Cellular Respiration
Brain pop:
Cellular Respiration

Bell Work
Copy & complete the following statement.
You may need to add a few sentences to
explain 
Cellular respiration is similar to
photosynthesis because ____________
Is he
correct?!
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Bell Work
C
C
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Assignment ISN p. 118
**IN COLOR!!!!** Be sure to read all
instructions carefully FIRST!!
Complete “Activities of Cell”
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Pictures of Organelles:
(this is what your illustrations should look like…..
Mitochondria:
Chloroplast:
CHECK YOUR ILLUSTRATION!!...
Copyright Cmassengale
Bellwork Tuesday
Draw a Venn Diagram …..
Compare and contrast photosynthesis and
cellular respiration using your diagram from
the “Activities in the Cell” worksheet from
Friday.!

Bell Work
F
J
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Bell Work
*Study for
your test
when you’re
done. 
D
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Bell
Work
G
H
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Bell Work
1. Flip through Ch. 6 in your book
1. Examine the artwork and images
1. Create a list of at least 8 items long
that demonstrate why the
information in ch. 6 is relevant to
your life. Why do you need to know
it?
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