* DNA replication: The cell has already replicated its DNA during the S phase of interphase. This means each chromosome now consists of two identical sister chromatids, held together at the centromere.
* Chromatin condensation: The duplicated DNA, which was loosely organized as chromatin fibers during interphase, begins to condense into compact, visible chromosomes. This process is facilitated by proteins called condensins.
* Centriole duplication: Centrioles, which play a critical role in organizing the microtubules of the spindle fibers, have also duplicated during interphase.
* Preparation for spindle formation: The duplicated centrioles begin to migrate towards opposite poles of the cell, setting the stage for the formation of the spindle apparatus, which will be used to separate the sister chromatids.
So, before prophase begins, the cell has already replicated its DNA, and the genetic material is prepared for the complex process of separation that will occur during prophase and the rest of mitosis.
