Each nucleus is genetically identical to the nucleus in the original cell (before Mitosis). Therefore, Mitosis creates two nuclei from one – each nucleus can serve as the nucleus of a new cell. When cytokinesis accompanies Mitosis, the cytoplasm divides, forming two distinct cells. Each cell contains its own nucleus (created by Mitosis). Cell division that features Mitosis allows one parent cell to divide into two genetically identical daughter cells.

Creating new cells is important for several reasons. Mitosis allows cell proliferation to develop a unicellular zygote into a multicellular organism, grow a multicellular organism, and create new cells to replace cells damaged by injury or infection in a multicellular organism. Mitosis offers a way for a unicellular, eukaryotic organism to reproduce.

As you review Mitosis, think about how Mitosis (as part of the M phase) fits into the cell cycle. Mitosis occurs in five phases.

  1. Prophase: During this first phase of Mitosis, the microtubules that make up the mitotic spindle begin forming on the two centrioles, and those centrioles start to move to opposite poles.
  2. Prometaphase: Construction of the mitotic spindle is completed, and the nuclear envelope disintegrates, allowing microtubules of the mitotic spindle to connect to replicated chromosomes.
  3. Metaphase: Replicated chromosomes (each consisting of two identical sister chromatids) move along the spindle tubules until all replicated chromosomes are aligned at the metaphase plate, midway between the poles.
  4. Anaphase: Each pair of sister chromatids (one pair for each replicated chromosome) separates and moves toward opposite poles. At this point, they are no longer called chromatids. Rather, each is an unreplicated chromosome.
  5. Telophase: The unreplicated chromosomes reach opposite poles. Each pole becomes a new nucleus, as each pole becomes enclosed by a new nuclear envelope. In most cases, cytokinesis (the division of the cytoplasm) occurs near the end of telophase, in which case the original cell is separated into two distinct cells, each with its own nucleus. Watch this video, which discusses the cell cycle. Make sure you can recognize the phases of Mitosis from the diagrams, as well as identify the difference between the parent and daughter cells.


 

Source: Messy Measy, https://youtu.be/-FZ41ZSoCqc
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