Prosesie.
lulelophase. MAT
1. Prophase
Normally, the genetic material in nucleus is in a loose thread-like form called chromatin)
At the onset of prophase, chromatin condenses into highly ordered structures called
chromosomes. Since the genetic material has already been duplicated earlier in s
phase, each chromosome is made of two sister chromatids, bound together at the same
centromere. Each chromosome also has kinetochore at centromere. Kinetochore is a
complex protein structure that is the point where spindle fibers attach).
There are two eentrioles (collectively called a centrosome) close to nucleus (recall from
Eshapter 4. Eigure 4.49). Each centriole duplicates and thus two daughter centrosomes
are formed. Both centrosomes migrate to the opposite poles of cell. Here, they give rise
to microtubules by joining tubulin proteins present in cytoplasm. The microtubules thus
formed are called spindle fibres. Complete set of spindle fibres is known as mitotic
spindle. By this time, nucleolus and nuclear envelope have degraded, and spindle
fibres have invaded the central space
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nucleus fiber are very important for our body
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