Videos
Mitosis in a vertebrate cell
Autor
Pickett-Heaps, Jeremy D.
Pickett-Heaps, Julianne
Resumen
Presents a cultured newt cell in late prophase. Chromosome condensation is well advanced, but the nuclear envelope is still visible at the periphery of the chromosomes. Shortly after the movie begins, the nuclear envelope disperses, and the influence of the spindle on the chromosomes becomes evident. The apparently random distribution of the chromosomes is modified by the action of the spindle, and many of the chromosomes move towards a region that runs across the space previously occupied by the nucleus from lower left to upper right. During this time, chromosome condensation continues, so each chromosome becomes slightly shorter, fatter, and darker (as seen in the phase microscope). With phase optics, the mitotic spindle itself is barely visible in this cell type. It can be identified in these images as a region on either side of the clustering chromosomes that appears particularly featureless. This appearance derives from the spindle's ability to exclude many granules and cytoplasmic organelles, like mitochondria, which have characteristic phase densities. Careful examination of the 'featureless' regions will show, however, a subtle fibrosity with just-detectable filaments that run from the chromosomal region to a point on either side of it; these points are the poles of the mitotic spindle Componente Curricular::Educação Superior::Ciências Biológicas::Biologia Geral