Cell division is a fundamental biological process that allows organisms to grow, repair damaged tissues, and reproduce. During cell division, a single parent cell splits into two or more daughter cells. There are two main types of cell division: mitosis, which produces identical cells for growth and repair, and meiosis, which creates genetically diverse gametes for reproduction.
Before any cell division can occur, the cell must first replicate its DNA during a phase called interphase. This is a crucial preparatory step that ensures each daughter cell will receive a complete and identical copy of the genetic information. During DNA replication, each chromosome is duplicated to form two identical sister chromatids that remain joined together at a structure called the centromere.
Mitosis is the process of nuclear division that produces two identical daughter nuclei. It consists of four distinct phases. During prophase, chromosomes condense and become visible while the nuclear envelope breaks down. In metaphase, chromosomes align at the center of the cell. Anaphase follows, where sister chromatids separate and move to opposite poles. Finally, in telophase, new nuclear envelopes form around each set of chromosomes.
Meiosis is a specialized type of cell division that produces gametes for sexual reproduction. Unlike mitosis, meiosis involves two consecutive divisions and reduces the chromosome number by half. During meiosis one, homologous chromosome pairs separate, creating two haploid cells. Then in meiosis two, sister chromatids separate, similar to mitosis, resulting in four genetically unique haploid gametes from one diploid parent cell.
Cytokinesis is the final stage of cell division where the cytoplasm physically divides to create two separate daughter cells. In animal cells, a contractile ring of proteins forms around the cell's equator and gradually pinches the cell membrane inward, creating a cleavage furrow. This process continues until the cell is completely divided into two identical daughter cells, each containing a complete set of chromosomes and cellular organelles.