Active Transport New

1. •Sodium-Potassium pump
•Types of molecules transport
•Endocytosis & Exocytosis

2. •Transport proteins within the membrane must
use energy (ATP) to move substances either to
the inside or outside of the membrane.
•Active transport requires the cell to spend
energy, usually in the form of ATP.
•Examples include transport of large molecules
(non-lipid soluble) and the sodium-potassium
pump.
WHAT IS ACTIVE TRANSPORT?

3. •Transport of molecules against a
concentration gradient (from regions of
low concentration to regions of high
concentration) with the aid of proteins in
the cell membrane and energy from ATP.

6. •The mechanism that uses ATP energy to
reset the sodium and potassium ions after
transmission of a nerve impulse.

7. SODIUM-POTASIUM PUMP:
•The sodium-potassium pump must break
ATP down into ADP in order to pump
sodium three ions outside the cell, while it
pumps two potassium ions into the cell.
•The ATP phosphorylates (adds a
phosphate to) the membrane protein as it
binds to the sodium and breaks down, and
it dephosphorylates the protein as it binds
with the potassium.

8. •Cellular respiration must occur to add the
phosphate back to ADP, thus restoring the
ATP.

11. •In the case of active transport, the proteins are
having to move against the concentration
gradient.
•For example the sodium-potassium pump in
nerve cells. Na+ is maintained at low
concentrations inside the cell and K+ is at higher
concentrations.
•The reverse is the case on the outside of the
cell.
•When a nerve message is propagated, the ions
pass across the membrane, thus sending the
message.

12. •After the message has passed, the ions
must be actively transported back to their
"starting positions" across the membrane.
•To reset them you must pick each one up,
again at an energy cost.
•Up to one-third of the ATP used by a
resting animal is used to reset the Na-K
pump.

13. Antiport transports the
solute in (or out) and
the co-transported
solute the opposite
direction.
One goes in the other
goes out or vice-
versa.
Symport transports
the solute and a
cotransported
solute at the same
time in the same
direction.
Uniport transports
one solute at a
time.

17. •An active process of taking in something through
a cell membrane, which uses energy (ATP).
•Is the case when a molecule causes the
cell membrane to bulge inward, forming a
vesicle.

19. •The opposite of endocytosis, is also an active
process.
•Exocytosis moves material to the outside.
•A vesicle fuses with the plasma membrane and
discharges its contents outside.
•This allows cells to secrete molecules.
•The incorporation of materials from outside the cell
by the formation of vesicles in the plasma
membrane.
•The vesicles surround the material so the cell can
engulf it.
•The fusion of vesicles to the plasma membrane
adds membrane to the cell surface.

23. Phagocytosis
refers to the
process of
engulfing large
particles.

25. •A vacuole is formed that contains the
material that has been engulfed.
•Known as cell eating.
•Phagocytosis is the cellular process of
engulfing solid particles by the cell
membrane to form an internal phagosome,
or "food vacuole.“
•The phagosome is usually delivered to the
lysosome, an organelle involved in the
breakdown of cellular components, which
fuses with the phagosome.

26. •The contents are subsequently degraded
and either released extracellularly via
exocytosis, or released intracellularly to
undergo further processing.
•Phagocytosis is involved in the acquisition of
nutrients for some cells, and in the immune
system it is a major mechanism used to
remove pathogens and cell debris.

27. •Bacteria, dead tissue cells, and small
mineral particles are all examples of objects
that may be phagocytosed.
•Phagocytosis is a specific form of
endocytosis involving the vesicular
internalization of solid particles, such as
bacteria.

29. •As in phagocytosis, a vesicle is formed which contains the
molecules that were brought into the cell.
•Vacuoles and vesicles produced by phagocytosis and
pinocytosis can fuse with lysosomes (lysosomes are
vesicles that contain digestive enzymes).
•Phagocytosis and pinocytosis remove membrane from cell
surface to form vacuoles that contain the engulfed material.
•Cell drinking.
•Pinocytosis refers to engulfing macromolecules.
•Occur when the external fluid is engulfed.

31. •In the process of pinocytosis the plasma
membrane froms an invagination.
•What ever substance is found within the area of
invagination is brought into the cell.
•In general this material will be dissolved in water
and thus this process is also refered to as "cellular
drinking" to indicate that liquids and material
dissolved in liquids are ingested by the cell.
•This is opposed to the ingestion of large
particulate material like bacteria or other cells or
cell debris.

33. Proton pumps operate both within the inner
mitochondrial membranes in the electron
transport system of cellular respiration,
and in chloroplast membranes during
photosynthesis.

35. In cotransport, one process (the Na-K
pump), is coupled with movement of a
molecule of sugar (glucose) out of the cell,
while allowing sodium to enter through the
protein.

37. •Receptors help to attach molecules to the
membrane before taking them in.
•Macromolecules bind to receptors on the
surface of the cell.
•Receptors with bound macromolecules
aggregate in one area and are brought into
the cell by endocytosis.

38. •The vesicle containing the macromolecules
can release the macromolecules into the cell
directly or they can be processed by
chemicals contained within lysosomes after
fusing with the lysosomes.
•The vesicle (and receptors) then returns to
the cell surface.
•Receptor-mediated endocytosis occurs when
the material to be transported binds to certain
specific molecules in the membrane.
•Examples include the transport of insulin and
cholesterol into animal cells.