MICROTUBULE

Size:

• diameter of 24 nm with a 5 nm thick wall, extend across the cell
  

Location:

• scattered all over the cell
  

Function:

Microtubules are hollow tubular structures made of the protein tubulin that are arranged into protofilaments, which are long rows in parallel alignment. Microtubules are part of the cytoskeleton as well and therefore function in the mechanical support of the cell. They help determine the shape of the cell and provide a kind of highway system for the movement of vesicles and organelles. Also, they form the mitotic spindle during cell division and compose the core of cilia and flagella of the cells that have them.

Related Organelles: Microfilament, Centriole, Centrosome