EOG89S8PH	GO:0005874	4/8	microtubule	cellular_component	"Any of the long, generally straight, hollow tubes of internal diameter 12-15 nm and external diameter 24 nm found in a wide variety of eukaryotic cells; each consists (usually) of 13 protofilaments of polymeric tubulin, staggered in such a manner that the tubulin monomers are arranged in a helical pattern on the microtubular surface, and with the alpha/beta axes of the tubulin subunits parallel to the long axis of the tubule; exist in equilibrium with pool of tubulin monomers and can be rapidly assembled or disassembled in response to physiological stimuli; concerned with force generation, e.g. in the spindle." [ISBN:0879693568]
EOG89S8PH	GO:0007021	4/8	tubulin complex assembly	biological_process	"The aggregation and bonding together of alpha- and beta-tubulin to form a tubulin heterodimer." [GOC:mah]