CENTROSOME AND CENTRIOLES ❖ Centrosome is an organelle that contains two cylindrical structures called centrioles that lie perpendicular to each other. ❖ Centrioles are surrounded by amorphous pericentriolar materials. ❖ Each centrioles has cartwheel-like organisation. ❖ Centriole is made up to 9 evenly spaced peripheral fibrils of tubulin protein. Each of the peripheral fibril is a triplet (9+0 arrangement). ❖ Adjacent triplets in centrioles are also linked. ❖ The central part of the proximal region of the centriole is called hub (proteinaceous in nature). ❖ Hub is connected with tubules of the peripheral triplets by radial spokes made of protein. FUNCTION ❖ In animal cells, centroiles play important role in initiation of cell division by forming spindle fibres that give rise to spindle apparatus. ❖ Form the basal body of cilia and flagella.