Centrioles are organelles not wrapped by membrane and participating in the process of cell division.
In complex fungal cells, superior plants (gymnosperms and angiosperms) and nematodes there are no centrioles. They are present in most animal cells, algae and lower plants such as bryophytes (mosses) and pteridophytes (ferns).
Structurally, consist of a total of nine trio of protein microtubules, which are arranged in a cylinder.
They are self-replicating in the period preceding cell division., then migrating to the opposite poles of the cell.
One of the steps that the cellular factory needs to take is the construction of new factories, ie their multiplication. This involves a prior elaboration of a series of protein scaffolds, the so-called split spindle, formed by numerous microtubule filaments.
Although these microtubules do not originate from the centrioles but from a region of the cell known as the centrosome, their participation in the process of dividing an animal cell is common.
Already in higher plant cells, as there are no centrioles, their multiplication takes place without them.