Centriole Definition
A centriole is a small cylindrical organelle found in animal cells near the nucleus. It is part of the centrosome and helps organize microtubules in the body. Centrioles play a crucial role in cell division by forming the spindle apparatus, which helps separate chromosomes during mitosis.
The function of a Centriole
Centrioles are small cylindrical organelles found in the cytoplasm of most eukaryotic cells, near the nucleus. They exist as part of the centrosome, which helps organize microtubules in the body.
Typically, a eukaryotic cell has one centriole that is at a right angle to a second centriole in the centrosome. Centrioles play an important role in organizing microtubules that serve as the cell’s skeletal system and help determine the locations of the nucleus and other organelles within the cell.
The main function of a centriole is to create and anchor microtubules in the cell. Microtubules extend from each centriole and use it as an anchor for their base. Each cell may have hundreds or thousands of microtubules that extend to various parts of the cell.
During normal cell functions, motor proteins attach to products tagged with special glycoproteins (sugar and protein) which act as signals to specific motor proteins. These proteins attach to vesicles carrying products or organelles that need to be transported along microtubules.
During mitosis, when a cell divides into two daughter cells, centrosomes are replicated. The new pair of centrioles move ahead of the spindle to opposite poles of the dividing cell.
The spindle fibers then distribute chromosomes in each daughter cell. In general, a centriole looks like a small hollow cylinder with nine bundles of microtubules arranged peripherally in a circle. However, some species have fewer than nine bundles.
Structure of a Centriole
A centriole is a small cylindrical organelle that exists as part of the centrosome, which helps organize microtubules in the body.
Typically, a eukaryotic cell has one centriole that is at a right angle to a second centriole in the centrosome. Centrioles are made up of nine sets of short microtubule triplets arranged in a cylinder.
However, deviations from this structure include crabs and Drosophila melanogaster embryos with nine doublets and Caenorhabditis elegans sperm cells and early embryos with nine singlets.
Each cell may have hundreds or thousands of microtubules that extend to various parts of the cell. During normal cell functions, motor proteins attach to microtubules and move along them to transport vesicles or other organelles within the cell.
During mitosis, centrosomes are replicated by duplicating each centriole. The four centrioles then divide into two centrosomes, each with one centriole at a right angle to the second centriole. Microtubules extend between the centrosomes which push the sets of centrioles apart.
Additional proteins found in a centriole include cenexin, tektin, and centrins. The main function of a centriole is to produce cilia during interphase and the aster and spindle during cell division.
