Short answers, pulled from the story.
A centriole is a cylindrical organelle found in most eukaryotic cells, composed mainly of a protein called tubulin. The standard structure consists of nine sets of short microtubule triplets arranged in a cylinder, along with additional proteins including centrin, cenexin, and tektin.
Centrioles help organize the mitotic spindle and complete cytokinesis during cell division. They replicate once per cell cycle during S phase, and each daughter cell inherits one mother-daughter centriole pair after mitosis.
In humans, the sperm donates two structurally distinct centrioles, the proximal centriole and the distal centriole, to the egg after fertilization. These sperm-derived centrioles form the first centrosome in the zygote and organize the microtubule network needed for the first embryonic cell division.
Failure of centrioles to migrate properly before ciliary assembly has been linked to Meckel-Gruber syndrome. More broadly, centriole dysfunction disrupts the formation of cilia and flagella, with consequences for development and organ function.
No. Conifers and flowering plants lack centrioles in all their cells. Centrioles are present only in the motile male gametes of certain plant groups including charophytes, bryophytes, seedless vascular plants, cycads, and Ginkgo.
The centrosome was discovered jointly by Walther Flemming in 1875 and Edouard Van Beneden in 1876. Van Beneden first observed that the centrosome is composed of two orthogonal centrioles in 1883. Theodor Boveri coined the term "centriole" in 1895.