Transcript centrioles

centrioles
• The Centrosome and the Centrioles
• ANIMAL CELL CENTROSOME: The
centrosome, also called the "microtubule
organizing center", is an area in the cell
where microtubles are produced.
•
• . Within an animal cell centrosome there is
a pair of small organelles, the centrioles,
each made up of a ring of nine groups of
microtubules. There are three fused
microtubules in each group.
• The two centrioles are arranged such that
one is perpendicular to the other.
• During animal cell division, the
centrosome divides and the centrioles
replicate (make new copies). The result is
two centrosomes, each with its own pair of
centrioles.
• The two centrosomes move to opposite
ends of the nucleus, and from each
centrosome, microtubules grow into a
"spindle" which is responsible for
separating replicated chromosomes into
the two daughter cells.
• PLANT CELL CENTROSOME: Plant cells
have centrosomes that function much like
animal cell centrosomes. However, unlike
centrosomes in animal cells, they do not
have centrioles.
• Centrioles are cylindrical structures that
are composed of groupings of
microtubules arranged in a 9 + 3 pattern.
• The pattern is so named because a ring of
nine microtubule "triplets" are arranged at
right angles to one another.
• Microtubules are one of the components
of the cytoskeleton. They have a diameter
of 25 nm and length varying from 200
nanometers to 25 micrometers.
Microtubules serve as structural
components within cells and are involved
in many cellular processes including
mitosis, cytokinesis, and vesicular
transport.
• Centrioles are found in animal cells and
play a role in cell division.
• Centrioles replicate in interphase stage of
mitosis and they help to organize the
assembly of microtubules during cell
division.
• Centrioles called "basal bodies" form cilia
and flagella.
• There are three fused microtubules in
each group. The two centrioles are
arranged such that one is perpendicular to
the other.
• Centrioles and Basal Bodies
Centrioles and Basal Bodies Basically these
are the same thing.
• A centriole is made up of nine (9) sets of triplet
microtubules.
• A centriole is commonly found in the
centrosome.
• A important note is that plant cells commonly do
not have centrioles and they are not required
for division.
• A triplet contains one complete microtubule
fused to two incomplete microtubules. The
centriole is a short cylinder-like structure.
• The centriole is important in the formation of
cilia or flagella, then it is called a basal body are
typically thought in relation to cilium or
flagellum, where as, centrioles are associated
with the cytoskeleton.
• Centrioles are surrounded by a densely staining
material pericentriolar material, this is where
most of the microtubules arise from, also in
cells without centrioles, the microtubules are
organized from this densely stained material.
• Centrioles as mentioned earlier are often
known for their role in cell division.
• Centrioles seem to determine the position
of the pericentriolar material, which in turn
affects the polarity of the cell.