Mitotic

Mitotic refers to mitosis, the division of a eukaryotic cell's nucleus and genetic material to produce two genetically identical daughter cells. It is part of the cell cycle’s M phase, following DNA replication in S phase. During mitosis, the chromosomes condense, align, and segregate to opposite poles, followed by cytokinesis that divides the cytoplasm and completes cell division.

The process is classically described in stages. Prophase involves chromosome condensation and the formation of the mitotic spindle. In prometaphase, the nuclear envelope breaks down and microtubules attach to kinetochores. Metaphase features chromosomes aligned at the metaphase plate. Anaphase drives the separation of sister chromatids toward opposite poles. Telophase reassembles nuclei, and cytokinesis completes cytoplasmic division, producing two distinct daughter cells.

Regulation of mitosis depends on a network of signaling pathways. Cyclin-dependent kinases (CDKs) paired with specific cyclins control progression through the stages. The spindle assembly checkpoint monitors proper chromosome attachment before anaphase proceeds. Key molecular events include the activation of separase to cleave cohesins that hold sister chromatids together, and the coordinated action of motor proteins and microtubules to move chromosomes.

Mitotic fidelity is critical for development and tissue homeostasis; errors can cause aneuploidy and contribute to cancer. In histology and pathology, terms such as mitotic index and mitotic figures describe cell proliferation and mitotic activity.

There are organism-specific differences, such as plant cells forming a cell plate during cytokinesis, whereas animal cells form a contractile actomyosin ring. Despite variations, the core mechanisms of mitosis are highly conserved across eukaryotes.