Download Movement through the Cell Notes

Unit 5
Movement Through
The cell
Plasma Membrane/Cell Membrane
Why is the cell membrane important?
Selectively Permeable: A membrane that
allows some substances to pass through while
keeping others out.
The cell membrane is like a Fish net…lets water in and
out, but keeps the fish in
Plasma Membrane/Cell Membrane
Why is the cell membrane important?
Cell Membrane: Flexible, selectively
permeable boundary that helps control what
enters and leaves the cell.
Plasma Membrane/Cell Membrane
What are the 2 main parts of the cell membrane?
1. Phospholipid bilayer: 2 layers of lipids (fat)
Plasma Membrane/Cell Membrane
What are the 2 main parts of the cell membrane?
2. Protein pump/channel: Proteins that help
move large materials across the cell membrane
Homeostasis
What is homeostasis?
Homeostasis: Regulation of an organism’s
internal environment to maintain conditions
needed for life.
Running increases
body temperature
Panting decreases
body temperature
Homeostasis
What is homeostasis?
If you sweat, you lose water….
You get dehydrated….
You are not in homeostasis!
If you drink water, and replace
water levels…
You feel good…
You ARE in homeostasis!
Homeostasis
What is homeostasis?
If you have a fever….
If you don’t have a fever…
You don’t feel good….
You feel good…
You are not in homeostasis!
You ARE in homeostasis!
Homeostasis
What is homeostasis?
Diabetics can’t regulate sugar levels
If your sugar is too high….
The blood is like syrup…too thick…
Insulin Shots lower sugar levels
If your sugar level is normal…
Blood can’t flow…you don’t feel good….
Blood can flow…you feel good…
You are not in homeostasis!
You ARE back in homeostasis!
Clicker Question #1
A cell membrane is like a window
screen because:
a. it provides support
b. it prevents water from entering
c. it controls what enters & leaves the cell
d. it prevents everything from leaving
Clicker Question #2
These allow larger substances to move into
and out of the cell membrane:
a.
b.
c.
d.
Lipids
Phospholipid bilayer
Carbohydrate pumps
Protein pumps
Clicker Question #3
This is another name for the
cell membrane:
a.
b.
c.
d.
Nucleus
Phospholipid bilayer
Homeostasis
Protein pump
Clicker Question #4
What is a word that can be
associated with “homeostasis”?
a.
b.
c.
d.
Balance
Unbalance
Fluctuate
Unstable
Review….
Solute: Any substance (like salt) that is dissolved in
water is a solute.
Solution:
The combination of a solute (salt) and
solvent (water).
Example: salt in water = saltwater
Concentration:
Of a solution is the mass of solute in
a given volume of solution.
Concentration just means how salty the water is
Remember…
Nature wants to be balanced!
One of the most important functions of
the cell membrane is to regulate the
movement of molecules from one side
of the membrane to the other.
Passive Transport
Passive Transport: The movement of
molecules from an area of high concentration
to an area of low concentration WITHOUT the
use of energy.
There are 2 Types of Passive Transport
a. Diffusion
b. Facilitated Transport
The next several slides are about the transport of molecules
across the cell membrane that does NOT require ENERGY
What are the types of movement through the membrane?
Diffusion is a type of movement of molecules through
the cell membrane where the molecules move from an
area of HIGHER concentration to an area of LESSER
concentration.
Example: Like moving from the city to the country
Higher
Concentration
Lower
Concentration
What is Diffusion?
Diffusion causes many substances to move across
a cell membrane but does NOT require the cell
to use energy.
Diffusion tries to get the solute molecules to be
equal on each side of the membrane.
When both sides of the membrane are equal in
terms of solute, the cell is in equilibrium.
All cells try to attain equilibrium (BALANCE)!
Osmosis & Diffusion
The sound & video does not always match up…you don’t
have to point this out!...I know.
What are the types of movement through the
membrane?
If a substance is able to diffuse across a
membrane, the membrane is permeable to that
substance.
Example: A sponge is permeable.
Most cell membranes are selectively permeable
which means that some substances can pass
across easily and others cannot.
What is osmosis?
Osmosis is another type of movement across a membrane.
Osmosis is the diffusion of water through a selectively
permeable membrane.
Lets look at a sugar-water solution.
One side of the membrane has a concentrated sugar
solution and on the other side is a dilute sugar solution.
What type of molecule is sugar?
What does “Macro” mean?
Macromolecule
Large
Can sugar easily move across the membrane?
No
What is osmosis?
Sugar cannot move freely across the membrane
because it is too big.
The water moves from where there is more
water to the area where there is more sugar.
So—in this situation, the water moves from an
area of Low concentration of Solute to an area
of High concentration of Solute.
Water “Chases” the sugar!
What are the 3 types of solutions?
There are 3 types of solutions.
1. Hypertonic
2. Hypotonic
3. Isotonic
Hypotonic
Isotonic
Hypertonic
Isotonic
As you know a cell tries to reach
equilibrium. This equal state is also known
as an Isotonic solution.
Water is still moving in & out equally!
Hypotonic
Example of a Hypotonic solution: Freshwater (no solute)
The cell will have more salt in it and less outside of it.
In a Hypotonic solution, water rushes into the cell causing
the cell to expand and eventually burst.
Water “Chases” the solute into the cell
HIGH
Concentration
Low
Concentration
How to Remember!!!!
Hypo = EXPLODE
Hypertonic
Example of a Hypertonic solution: Saltwater
The cell will have less salt in it and MORE outside of it.
In a Hypertonic solution, water rushes out of the cell causing
the cell to shrivel and shrink.
Water “Chases” the solute out of the cell
How to Remember!!!!
Hyper = shrink
Cells in Solutions
Hypo = Below
Hypo = Explode
.1%
Salt
Iso = Same
15%
15%
15%
Salt
.1%
5%
5%
Salt
5%
15%
Hyper = Above
Hyper = Shrink
5%
What is facilitated diffusion?
Facilitated Diffusion is a process in which the cell membrane uses
the protein channels to allow/help bigger molecules such as ions,
sugars, and salts to cross in either direction.
Solute
Cell Membrane
Protein Channel
This is still diffusion! No energy is used to move these
molecules. The protein channels just “help” the molecules
across.
Video
1. The membrane encloses the cell & keeps it _______ inside.
2. Molecules are always on the ______.
3. Molecules move _____ a concentration gradient.
4. Is energy added during passive transport?
5. When the solution is low, the cell will ________.
Video
Video Questions
Answers
stable inside.
1. The membrane encloses the cell & keeps it _______
move
2. Molecules are always on the ______.
down a concentration gradient.
3. Molecules move ________
4. Is energy added during passive transport?
NO
Swell & may burst
5. When the solution is low, the cell will ____________________.
Active Transport
NEEDS ENERGY!
To High
From Low
What type of cellular movement requires energy?
Sometimes, molecules move against the concentration
gradient. This means that they are going from a lower
area of solute to a higher area of solute. They are crazy!
For this, they need energy to move against the
gradient/difference.
Example: Like walking up a hill.
You’ll need
ATP = Energy
ENERGY!
What type of cellular movement requires energy?
Active Transport uses the protein channels to move
these molecules against the gradient with the
input of energy.
This is the only movement that requires
energy!
This type of transport is often referred to as a
pump.
ENERGY!
1
2
3
Low
HIGH
concentration
of solute
concentration
of solute
1
2
3
4
5
Video
1. Moving against the gradient requires _______.
2. Some materials move into & out of cells against their
concentration gradient. It is called ________.
3. Active transport is sometimes called a ______.
4. Some large molecules must be absorbed into cells by
a process called _________.
5. Think of exo- for ______.
Video…a little long….will not see all of it
Video Questions
Answers
Energy
1. Moving against the gradient requires _______.
2. Some materials move into & out of cells
against their concentration gradient. It is
Active Transport
called ___________.
Pump
3. Active transport is sometimes called a ______.
4. Some large molecules must be absorbed into
Endocytosis
cells by a process called ____________.
Exit
5. Think of exo- for ______.
What are 2 types of Active Transport?
There are 2 types of Active Transport
1. Endocytosis is the process of taking material into
the cell by means of in-foldings, or pockets, of the cell
membrane.
This pocket, breaks loose from the cell membrane and
forms a type of vacuole within the cytoplasm.
Large molecules, like food and other cells can be taken
up by endocytosis.
Endocytosis
2. Phagocytosis is the process of large particles
being taken into the cell by means of
extensions of cytoplasm that go out and engulf
the large particles.
This is a leukocyte (white blood cell) in
your blood that is shooting out extensions
to get the large particles that you see.
2 Types of Active Transport
2.
Exocytosis is the cell’s ability to remove large
amounts of materials out of the cell.
During exocytosis, the membrane of the vacuole
surrounding the material fuses with the cell membrane,
forcing the contents out of the cell.
The End