A small organelle that can be found in all of the animal cells and few plant cells. It locates near to the nucleus and as a part of centrosome. Also, it presents in the form of two cylinders that one of them is mother centriole and the other one is daughter centriole pair up at the right angle.
The centriole is formed by numbers of microtubule triplet joining together and each three mircotubule triplets as a group. Each group connected by the connecting fibrils. The centriole is one of the examples of "9+2" pattern and this pattern can be seen in the cross-section of it.
The main function of centriole is forming spindle fibres during cell division. In prophase, spindle fibres started forming in centriole and then appear in centrosome. After that, in prometaphase, spindle fibres attach to the kinetochores in centromeres of chromsomes. Following this, in anaphase, sister chromosomes separated and each of them moves to the opposite ends by the attachment of spindle fibres.