Final answer:
The incorrect statement about centrioles is that they are amorphous; in reality, they are structured with a 'nine triplet' arrangement of microtubules.
Step-by-step explanation:
Among the statements given about centrioles, the one that is incorrect is that they are amorphous. Centrioles are indeed surrounded by pericentriolar material (PCM), exist in pairs, and are part of a microtubule organizing center. Moreover, each centriole is a barrel-shaped structure made up of microtubules arranged in a characteristic 'nine triplet' pattern, which means each centriole consists of a cylinder containing nine sets of triplet microtubules arranged around its perimeter, with accessory proteins holding these triplets together. This 'nine triplet' organization is a key feature of their structure, allowing them to assist in cell division by arranging the mitotic spindles.