Centriole

A centriole is a small structure made of microtubules which exists as part of the centrosomewhich helps organise microtubules in the body. A centriole is the main unit that creates and anchors microtubules in the body. cell. Generally, a eukaryotic cell has a centriole that forms a right angle with a second centriole in the centrosome. Microtubules extend from each centriole and use the centriole as an anchor for the base of each microtubule. Each cell may have hundreds or thousands of microtubules extending to various parts of the cell. During normal cellular functions, motor proteins bind to both microtubules and an element to be transported. The motor proteins crawl along the microtubules, carrying with them any substance or compartment. Not all cells contain centrioles, and other methods are used to create microtubules.

Function of a centriole

The cells form a endoskeleton microtubule complex that allows substances to be transported anywhere in the cell. The products are labelled with glycoproteins (sugar and protein) that act as signals for specific motor proteins. These proteins attach to the product, or vesicle in which the product is stored, and also attach to a microtubule. Microtubules are arranged in the centriole, of which each centrosome has two. The centrioles anchor the microtubules extending from it and contain the factors needed to create more tubules.

During mitosisthe centrosomes replicate by duplicating each centriole. The 4 centrioles then divide into two centrosomes, each with one centriole at right angles to the second centriole. Microtubules extend between the centrosomes separating the sets of centrioles. The centrioles will separate towards opposite ends of the cell. Once established, each centriole will extend the microtubules into the cytoplasm that seek out the chromosomes. Microtubules attach to chromosomes on their centromeres.which are parts of the DNA specially formulated to allow special proteins and microtubules to bind. The microtubules then disassemble from the centriole, which pulls the microtubule towards the centriole as the motor proteins pull the chromosomes apart.

Structure of a centriole

A centriole is made up of nine sets of microtubules, each in groups of three known as microtubules. triplet. Triplet microtubules are very strong because they are composed of three concentric rings of microtubules that form together. Triplet microtubules are seen in other strong microtubule structures, such as the basal bodies of cilia and flagella. Each triplet is bound together by special proteins that give it the shape of a centriole. Surrounding the triplet microtubules is an amorphous material called the pericentriolarwhich contains many of the molecules necessary for microtubule construction. Each microtubule in a triplet is made up of tiny units of tubulina small monomer that can be joined together to create long, hollow tubes that resemble straws. A 3D image of a single centriole can be seen below.

• Microtubule organising centre: a centrosome during mitosis, when a large network of microtubules is created.
• Centrosome: the centre of microtubule activity in a cell, consisting of two centrioles.
• Centromere: the portion of a chromosome to which it can bind via microtubule association proteins.
• Kinetochore: the specific region within a centromere that has the ability to form bonds with other molecules.