Microtubule dynamic instability - This shows slow growth and rapid depolymerization of the plus end, as well as microtubule release and depolymerization from the minus end. Things to try: during mitosis, the catastrophe frequency increases, resulting in shorter, more dynamic microtubules. You can see this by changing the catastrophe frequency from 0.042 to 0.15 for instance (you can change the parameters while the animation is running). Another microtubule phenomenon is treadmilling. You can see this by changing the "minus end depolym" rate from 0.8 to 0.12 (the same as the growth rate). References for parameters: PNAS 94: 5078, J Cell Biol 162: 963.
You can also run two animations side by side to compare the effects of changing parameters.
Microtubule dynamic instability (old version)
-- Programming limitation: once the microtubule is released, a new microtubule in its place can be nucleated. However, that new microtubule can't be released until the previously released microtubule has disappeared.
-- Two of them! In this case, microtubules are captured by the chromosomes, and when all the chromosomes are connected, the chromosomes move towards the poles, then the poles move apart, then the microtubule dynamics goes to interphase values.
-- Under construction: pauses during microtubule growth (e.g. J Cell Biol 145: 993); first attempt at tip complexes. Version with variable length scale
These are all actionscript 2 animations