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Mitosis is the cell‑cycle phase where condensed chromosomes migrate to the cell’s center, segregate into two nuclei, and the cell divides—thanks to a dynamic mitotic spindle. After this process, the parent cell becomes two identical daughter cells, each poised to grow and reenter the next cycle. (Cold Springs Harbor Perspectives in Biology, 2014)
Interphase precedes mitosis: the nucleus, nucleoli, and nuclear membrane remain intact while organelles produce energy and duplicate genetic material, forming homologous chromatids linked by a centromere. No division occurs yet.
During prophase, the sister chromatids become visible, resembling an X under a microscope. Microtubule strands assemble into a spindle that will later pull the chromatids apart. The nuclear envelope dissolves, releasing chromosome pairs into the cytoplasm.
In metaphase, spindle fibers grip the centromeres and align the chromatids along the cell’s equator—the metaphase plate. All chromosomes must be correctly attached before division proceeds. Some models insert an intermediate prometaphase stage.
Anaphase follows: motor proteins move the separated chromatids toward opposite poles, while spindle tension elongates the cell.
During telophase, new nuclear envelopes form around chromosomes at each pole, chromosomes begin to unwind, and the mitotic spindle dissolves. Cytoplasm and organelles are partitioned, and a cleavage furrow (or cell plate in plants) forms, completing cytokinesis.
In asexual reproduction, mitosis generates two genetically identical cells, ensuring rapid population maintenance. Checkpoints throughout mitosis guard against chromosomal errors, halting division if discrepancies arise.
By contrast, sexual reproduction relies on meiosis, where homologous chromosomes pair and exchange gene segments, creating genetic diversity and influencing phenotypic variation among offspring.
Many microorganisms depend on mitosis—or related processes like budding—to thrive. In multicellular organisms, mitosis governs the turnover of non‑reproductive cells (skin, muscle, blood), facilitating growth, wound healing, and daily cell renewal.
Some species can switch between asexual and sexual modes. For instance, diatoms predominantly reproduce asexually but undergo a specialized meiosis to restore cell size. A 2015 study in BioMed Central Genomics highlighted that sexual reproduction in diatoms not only enhances genetic diversity but also plays a critical role in size restitution.
