Answer:
It is slow growing.
Explanation:
It has been shown that microtubules have a positive end, capable of rapidly growing in length by addition of heterodimers, and a negative end, with a tendency to lose them if it is not stabilized. This is clearly seen when they are included in the centrosome. Thus, a permanent growth of a large number of microtubules is observed from the centrosome outwards, sometimes until reaching the plasmalema. Then it forms again and sometimes disappears. In this way the quantity and length of the microtubules are constantly modified, forming new patterns according to the needs of the cell. The speed of the processes is interpreted by considering that the half-life of each microtubule is about 10 minutes.
It should be remembered again that actin filaments are polar structures (the two ends polymerize at different speeds) and that each filament has one + (fast growth) and another - (slow growth) end. Actin G monomers bind more rapidly to the barbed end (+) than to the pointed (-), and under certain conditions, aggregation is carried out at the barbed end, while disaggregation occurs simultaneously at the end pointed. In this case, actin monomers circulate through actin F from the spiked end to the pointed end. Slight changes in the speed of aggregation (at the barbed end) or of deaggregation (at the pointed end) will determine if the microfilament is lengthened or shortened.
To recognize the polarity, the S1 heads of the myosin are attached to the end - or pointed.
