Meaning of Centrioles
Centrioles are cytoplasmic organelles present in eukaryotic cells, except cells of fungi and seed plants (gymnosperms and angiosperms). They aid in the separation of genetic material in cell division and can form cilia and flagella.
They are hollow structures, made up of nine sets of three microtubules linked by adhesive proteins, which are located in a region of the cell called the centrosome or cell center.
Centrosomes are of fundamental importance for the process of cell division, being responsible for the formation of the achromatic spindle, which corresponds to a set of microtubules arranged at the poles of the cells that lead to the separation of homologous chromosomes during mitosis and meiosis. .
Centrioles also function in the formation of cilia and flagella, structures involved in locomotion and specialized cell lining. Therefore, they migrate from the centrosome to the periphery of the cell and grow by stretching their microtubules.
During this growth, the plasma membrane accompanies them, wrapping them like a glove.
Although the constitution of the eyelashes and flagella is identical, they differ in size and type of movement.
They are shorter than the flagella and have a locomotor function. They occur in cells in greater numbers than flagella and move in a whip-like manner.
They are found, for example, in some groups of protozoa, helping them to move in the aqueous medium, and also in cells such as those lining the human trachea. In these cells, the cilia have the function of expelling the mucus that lubricates the respiratory tract, ridding the body of bacteria and particles inhaled with air.
Larger, flagella move through corrugations, which extend from the base to the free end of the filament. They can also be found in organisms such as protozoa and in reproductive cells.
The human spermatozoon, for example, has a flagellum that measures about 40 µm, responsible for propelling it on the way against the oocyte. The gametes of some plants can even have flagella.