Transcript Cell Membrane is - Garnet Valley School District

Chapter 2
Section 3
Life Science
THE
Cell Membrane
Cells survive by allowing some items
to pass through the cell membrane.
 ***Cell Membrane is “Selectively
Permeable”


Selectively Permeable- “selects”
certain materials to go in and out of the
cell membrane.
2 types of Movement through
the Cell Membrane:
1.
Passive Transport- does not
require energy to pass through cell
membrane
2.
Active Transport- requires energy
Mrs. C’s Hill
FOCUS:
Passive Transport

The movement of substances through
the cell membrane without the input
of energy is called Passive Transport.

There are three types of Passive
Transport that can occur.
1st Type of Passive
Transport
 Diffusion-
movement of
“molecules” from an area of high
concentration to low concentration.
Examples- Glade molecules diffusing
across classroom  or
 Oxygen and Carbon Dioxide
molecules moving across membrane

EQUILIBRIUM

Ending Result- Equilibrium

This is when it’s EQUAL on both sides
– BALANCED!!!
Balance the smiley faces     
2nd Type of Passive
Transport

Osmosis- movement of water from
an area of high concentration to low
concentration

Examples- Dying Plant (needs H2O)
EQUILIBRIUM

Ending Result... Equilibrium

This is when it’s EQUAL on both sides
– BALANCE!!!
Balance the H2O molecules
3rd Type of Passive
Transport

Facilitated Diffusion- Diffusion that is
helped by transport proteins with
NO energy needed.
 Like
a “revolving door”
– When large items are too big to pass
through the cell membrane they enter
with “help” from transport proteins !!!
(squeezing through)
Ending Result???

Ending Result... Equilibrium

This is when there is the same amount
of items on both sides.
– BALANCE!!!

Examples- Sugar molecules entering
cells; Minerals entering plant roots.
•
Think of student at bottom of hill…
•
What type of Transport requires Energy?
•
Active Transport!


Active Transport involves…
Transport Proteins and Energy are
used to move materials through cell
membrane

Examples- A Soccer/Football Game;
Overtime requires a lot of extra
energy.

Balance the glucose molecules
Active Transport

What if items are too big to pass
through the Transport Proteins?

When items are too big, the cell
membrane folds in on itself and
encloses the item in a sphere called a
vesicle (or vacuole).
 Example of Plastic Bag…
How do items enter???
1. Endocytosis- when items are
surrounded by the cell membrane
and create a vesicle/vacuole (“a
pod”)
2. Exocytosis- when large items are
passed out of the cell by having the
vesicle/vacuole attach to the cell
membrane and open up to the
outside.