mitosis

Cell division producing two genetically identical daughter cells. The engine of growth, repair, and asexual reproduction.

phases

1. prophase: chromatin condenses into chromosomes, spindle fibers form, nuclear envelope begins to dissolve
2. metaphase: chromosomes align at the cell equator (metaphase plate), spindle fibers attach to centromeres
3. anaphase: sister chromatids separate and move to opposite poles
4. telophase: nuclear envelopes reform around each set of chromosomes, chromatin decondenses
5. cytokinesis: cytoplasm divides, producing two separate cells

regulation

The cell cycle is controlled by cyclins and cyclin-dependent kinases (CDKs). Checkpoints (G1, G2, M) verify DNA integrity before proceeding. Failure of regulation leads to uncontrolled division — cancer.

biological role

• growth: increasing cell number during development
• repair: replacing damaged or dead cells
• asexual reproduction: single-celled organisms, budding

connections

Complemented by apoptosis (programmed cell death) — growth balanced by removal. Distinguished from meiosis, which produces genetically diverse haploid cells. DNA replication before mitosis depends on transcription machinery. Cell structure maintained by polymerization of cytoskeletal proteins.