Centriole;
Centrioles are present in animal cells, some microorganisms and lower plants. They are absent in higher plants.
Centrioles are short bundles of filaments, set at right angles to each other. They are found in a clear area of cytoplasm known as the centrosome.
Centrosome is a region close to nucleus where Centrioles are present.
In a cross section, each centriole consists of a cylindrical array of 9 microtubules,each microtubule has 3 tubules. The tubules are composed of special protein caned tubulin.
The chemical composition and structure is similar to that of cilia and flagella.
Their function is the formation of spindle (that guides the chromosomes during cell division). In addition to spindle formation, the centrioles act as the centre of formation for the whole cytoskeleton and they are known as microtubule organizing centres.
Types of Centriole;
Microfilament; They are cylindrical in shape and composed of contractile actin protein, linked to inner face of plasma membrane, they are involved in cyclosis (motion of cytosol)
Intermediate filaments; they have intermediate diameter between microtubules and Microfilaments, mention cell shape.
Microtubules; they are long, slender tubulin protein structure. They help in cell division.