MICROTUBULES

• Discovered by De Robertis and Franchi.
• Term given by Slautterback.
• These are hollow structures, consists of tubulin protein.
• Each protein diamer made up of a and b monomers.
• Diameter of microtubules = 25 nm
• Present in centrioles, cilia, flagella, spindle fibres.
• Absent in amoeba, prokaryotes (Blue green algae and bacteria)
• In plant microtubules often found associated to cell wall. Possibly these transport cell wall material from Golgi body to outside of cell. During cell division these become, distinct and form spindle fibers.