Download Passive Transport

Active Transport
Active Transport
• Active transport is the
movement of molecules
from an area of low
concentration to high
concentration
• This takes molecules
from outside the cell
and moves them inside
• These processes take
energy
Active Transport
• There are two main
types of active
transport
– Pumps
– Vesicles
• These two processes
require energy and
move molecules “up” a
concentration gradient
Cell Membrane Pumps
• Membrane proteins can
help both active and
passive transport
• Membrane proteins
that assist active
transport are referred
to as Cell Membrane
Pumps
• These pumps assist
charged particles into
the cell
Cell Membrane Pumps
• These pumps are a little
different than the passive
transport carrier proteins
• These have a certain
amount of binding sites
• These binding sites will fill
with ions or other small
molecules
• Once those are full, the
cell uses energy to move
the molecules into or out
of the cell
Cell Membrane Pumps
• The energy that is used
by these pumps is ATP
• ATP is a molecule that
supplies energy when it
is broken apart
• After it is broken the
cell can use the energy
that is released
Sodium Potassium Pump
• One example of active
transport in animal cells
is the sodium potassium
pump
• This pump carries
sodium and potassium
up their concentration
gradients
Sodium Potassium Pump
• Sodium is an element that
can be toxic to a cell in
high enough
concentration
• https://www.youtube.co
m/watch?v=NTFBXJ3Zd_4
• Potassium is something
that a cell needs for many
processes however it is
not always found in
abundance in the
environment
Sodium Potassium Pump
• The pump starts by
binding three sodium
atoms from inside the
cell
• With some energy, the
sodium ions are
released from the cell
Sodium Potassium Pump
• Next two potassium
ions are attached to the
protein pump
• With some energy from
ATP, the potassium ions
are brought into the cell
Movement in Vesicles
• Many times there are
molecules that are too
large to fit through the
carrier proteins and
membrane pumps
• These macromolecules,
nutrients and molecules
need to be brought into
the cell in other ways
Endocytosis
• A cell can take in external
fluid, large particles and
dissolved particles
• It does this by creating an
indent in its cell
membrane
• The cell membrane then
creates a small pouch
called a vesicle
• The vesicle is brought in
to the golgi apparatus
Endocytosis
• When large molecules
needs to be brought
into the cell, the cell
goes through
endocytosis
• Endocytosis is the
process of making a
vesicle out of cell
membrane
Endocytosis
• What is actually in the
vesicle determines what
kind of endocytosis it is
• Pinocytosis involves the
movement and
transport of solutes and
fluids
• Phagocytosis is the
movement of large
molecules, bacteria or
viruses
Endocytosis
• Receptor–mediated
endocytosis is a specific
type of active transport
that only happens when
receptors on the cell
surface pick up specific
molecules
• When the receptors
engulf the molecules, a
coated vesicle is formed
and the cell can bring it
where it needs to go
Exocytosis
• Exocytosis is the
process by which a
substance is released
from the cell
• Exocytosis is a process
that requires energy to
create the vesicles
involved
Exocytosis
• During exocytosis a cell
takes a vesicle and fuses it
with its plasma
membrane
• During this process a cell
releases what ever was
contained within the
vesicle
• It can be a large molecule,
several small molecules
or things dissolved