Centrioles

These cylindric organelles take part in cell division as an organizing center for microtubules. They are in fact composed of tubulin in a characteristic arrangement of nine microtubular triplets. A single pair of centrioles leaning at a 90 degree angle to one another is found near the Golgi complex in non-dividing cells. Before cell division each centriole duplicates itself. During mitosis a pair of centrioles moves to opposite poles of the cell to become the organizing centers for the mitotic spindle.