There are two main types of transport across the cell membrane - passive transport and active transport. Passive transport includes simple diffusion, osmosis, and facilitated diffusion, which move molecules across the membrane down their concentration gradient without requiring energy. Active transport includes the sodium-potassium pump and exocytosis/endocytosis, which all use energy to move molecules against their concentration gradient or to release/take molecules into/out of the cell.

2. Transport Across The Cell Membrane
Passive Transport Active Transport
*Osmosis
*Facilitated
Diffusion
*Simple
Diffusion
*Na/K
pump
*Exocytosis
Endocytosis
*Phagocytosis *Receptor
Mediated
*Pinocytosis
Your Job: One at a time, select the terms with a
red astric. It will direct you to a page with an
animation. You must then complete the answer
sheet located on my google classroom.

3. Simple Diffusion
Inside
Cell
Outside
Cell
Simple diffusion is an
example of how small
particles of any kind
cross the membrane
from a high to low
concentration, or down
its concentration
gradient with the use of
no energy.

4. Osmosis
Osmosis is just simple diffusion of water. Water movement
gets its own special name because of its importance.
Remember this- water moves to where there is less
concentration of water.

5. Facilitated Diffusion
Protein
Channel
Facilitated
diffusion uses a
protein channel to
allow larger
molecules in from
a higher to lower
concentration. Two
such molecules are
glucose and amino
acids. Once again,
no energy is
required, just a
concentration
gradient.

6. Na/K Pump
The Na/K pump uses
active transport to
move three sodium
atoms out and brings
in two potassium
atoms. This is
necessary because the
cell membrane is not
leak proof and must
constantly monitor
what ions need to be
in or out.

7. Exocytosis
Exocytosis is the
process by which
energy is used to
form a vesicle made
of phospholipids to
release either cell
products or waste to
the extracellular fluid.

8. Endocytosis- Phagocytosis
Phagocytosis is a form
of endocytosis
whereby a cell, such
as a white blood cell,
will consume an
unwanted substance
in the body, such as
bacteria, and destroy
it.

9. Endocytosis- Pinocytosis
Pinocytosis endocytosis
is a simple method of
bringing in necessary
substances, such as
water, into the cell by
pinching in the
phospholipid bilayer
thus creating a vesicle.

10. Endocytosis- Receptor Mediated
Receptor mediated
endocytosis is a
method where a
common virus enters
the cell. The virus
contains surface
protein markers that
the cell is familiar
with and it tricks the
cell to take it in.