1. Cell Processes: Moving In and Out of the Cell

2. A cell can only survive if food molecules are taken in and if waste materials are removed.
Materials enter and leave the cell through the cell membrane.

3. Cell Membranes Permeable Membrane Impermeable Membrane
allows all substances to pass through
Impermeable Membrane
does NOT allow substances to pass through
Most cell membranes allow only certain substances to pass through them and are called
Selectively Permeable (or semi-permeable)

4. A cell does NOT need to use energy to move particles from areas of high concentration (crowded) to areas of low concentration (less crowded).
This type of movement is called diffusion.

5. Osmosis
the diffusion of WATER through a cell membrane

6. Some substances enter and leave a cell by passing through protein doorways, also called channels.
Passive transport
High to low; NO energy is required.
Active Transport
Low to high; energy IS required (ATP)

7. Under Flaps Passive transport Active Transport
The movement of particles from areas of high concentration to areas of low concentration through protein doorways.
Active Transport
The movement of particles from areas of low concentration to areas of high concentration with the use of energy.

8. All cells live in a liquid environment in which materials such as salts and gases are dissolved.

9. * Concentration * Equilibrium
How crowded together the particles of these materials are in a liquid
* Equilibrium
When the concentration of particles is the same inside and outside the cell

10. There’s a higher
concentration of
particles outside
the cell than inside.
Particles move into
the cell.
The concentration
of particles is the
same inside & outside
the cell (equilibrium).

11. There’s a higher
concentration of
particles inside
the cell than outside.
Particles move out
of the cell.
The concentration
of particles is the
same inside & outside
the cell (equilibrium).

12. Particles that are too large to pass easily through the membrane can enter a cell by endocytosis.
Once the particle
is completely
surrounded, a vesicle
pinches off.
The cell comes in
contact with a
particle.
The cell membrane
begins to wrap around
the particle

13. Large particles can leave a cell by exocytosis. (exit)
Large particles that
must leave the cell
are packaged in
vesicles
The vesicle travels to
the cell membrane
and fuses with it
The cell releases
the particles into
the environment