Centrioles

A centriole is one of the very few organelles in this chapter that has no surrounding membrane at all - it is described as a non-membranous organelle. Structurally, it is built from nine peripheral triplet fibrils, each made of the protein tubulin, arranged in a ring around a central core called the hub. The hub itself is connected out to each of the nine peripheral triplets by thin radial spokes, giving the whole structure what is described as a '9+0' arrangement (nine peripheral triplets, nothing in the centre - distinct from the '9+2' arrangement seen later in cilia and flagella). Functionally, the centriole does two important jobs. It acts as the basal body from which cilia or flagella actually grow, essentially serving as the anchoring and organising structure at their base. And, during cell division in …