Cell-to-cell recognition
area
Bulk Transport fill-in-the-blank
glycolipids
large quantities
Large distances
glycoproteins
Bulk transport is actually a type of active transport. Bulk transport allows substances to be transported
in large quantities using energy*.
*Water moving up vessel elements is not considered bulk transport. However, sugar moving into the sieve-tube elements is.
, the cell’s way of releasing molecules out of the cell, is an example of bulk transport.
Using energy, the Golgi body releases vesicles containing substances that need to be “shipped out.” The
vesicles touch the cell membrane, turn “inside out,” and release the substances.
Exocytosis also allows the cell to much add area to its lipid bilayer. The vesicle that turns inside out
increases the cell’s surface area. These vesicles could also allow the membrane to obtain membrane
and
for
. Steps 3 and 4 describes how vesicles fuse with the cellular membrane
and its effect.
Step 3: The vesicle with transmembrane proteins and other substances are shipped out of the Golgi body.
Step 4: The vesicle touches the plasma membrane, turning inside out and exposing the transmembrane proteins
and other cell-to-cell recognition molecules.
receptor mediated
endocytosis
Ligand
phagocytosis
Unspecific
Specific
Pseudopodium
pinocytosis
Lysosomes
reduced
molecules
into
endocytosis
Contrasting exocytosis,
transports large quantities of substances
endocytosis, the cell’s surface area is
The bulk transport mechanism called
the cell. In all cases of
as the cell engulfs substances it needs.
, “cellular eating,” allows a molecule to engulf large
molecules and “eat” them. Using
(“false feet”), the cell would wrap around food and
consume it. The food is then digested using
. Amoebas are highly reliant on phagocytosis, as they are
heterotropic organisms.
Another bulk transport mechanism called pinocytosis, “cellular drinking,” allows the cell to consume
fluids using energy. However, the cell doesn’t need the fluids themselves, but rather the molecules in the
droplets. When a cell does pinocytosis, the cell is unspecific about what molecules it drinks.
Of all the endocytosis mechanisms discussed,
acquire
(RME) enables the cell to
substances that it needs using energy. Any substance that a cell specifically needs is called a
. They attach to receptors on the cell’s plasma membrane, causing RME to occur, allowing the cell to
acquire the in large quantities. An example of ligands in the human body are LDLs (“healthy fats,” as described
in a health class). Since body cells need LDLs, LDLs will attach to receptors, allowing cells to consume LDLs
in large quantities.