Glycocalyx
Glycocalyx is a
strictly, sugary envelope composed of polysaccharides and/or
polypeptides that
surround the cell. Glycocalyx is found in one or two states. It can be
firmly attached to
the cell’s surface, called capsule, or loosely attaché, called slime layer.
A slime layer is
water-soluble and is used by the prokaryotic to adhere to surfaces
external to the cell.
Glycicalyx is used by
a prokaryotic cell to protect it against attack from the body’s
immune system.
Flagella
Flagella made of
protein and appear “whip-like.” They are used by the prokaryotic cell
for mobility.
Flagella propel the microorganism away from harm and towards food in a
movement known as
taxis. Movement caused by a light stimulus is referred to as
phototaxis and a
chemical stimulus causes a chemotaxis movement to occur.
Flagella can exist in
the following form
Monotrichous: One
Flagellum
Lophotrichus: Two or
more Flagella that are at one end of the cell
Amphitrichous:
Flagella at two ends of the cell.
Endoflagellum: A type
of amphitrichous flagellum that is tightly wrapped around
spirochetes. A
spirochete is a spiral-shaped bacterium that moves in a corkscrew motion.
Borrelia
burgdorferi, which is the bacterium that causes lyme disease, exhibits an
endoflagellum.
Fimbriae
Fimbrae are
proteinaceous, sticky, bristle-like projections used by cells to attach to each
other and to objects
around them. Neiseseria gonorrhoeae, the bacterium that causes
gonorrhea uses
fimbriae to adhere to the body and to cluster cells of bacteria.
Pili
Pili are tubules that
are used to transfer DNA from one cell to another cell similar to
tubes used to fuels
aircraft in flight. Some are also used to attach one cell to another cell.
The tubules are made
of protein and are shorter in length than flagella and longer than
fimbriae
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