Centriole

In cell biology a centriole is a cylindrical organelle composed mainly of a protein called tubulin. Centrioles are found in most eukaryotic cells, but are not present in conifers (Pinophyta), flowering plants (angiosperms) and most fungi, and are only present in the male gametes of charophytes, bryophytes, seedless vascular plants, cycads, and Ginkgo. A bound pair of centrioles, surrounded by a highly ordered mass of dense material, called the pericentriolar material (PCM), makes up a structure called a centrosome.

See also: Centrosome
Cell biology
centrosome
Components of a typical centrosome:
  1. Centriole
  2. Mother centriole
  3. Daughter centriole
  4. Distal ends
  5. Distal appendages
  6. Subdistal appendages
  7. Proximal ends
  8. Microtubule triplets
  9. Interconnecting fibers
  10. Microtubules
  11. Pericentriolar material

Centrioles are typically made up of nine sets of short microtubule triplets, arranged in a cylinder. Deviations from this structure include crabs and Drosophila melanogaster embryos, with nine doublets, and Caenorhabditis elegans sperm cells and early embryos, with nine singlets. Additional proteins include centrin, cenexin and tektin.

The main function of centrioles is to produce cilia during interphase and the aster and the spindle during cell division.

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