Sejtosztódásra

Sejtosztódásra, or cell division, is a fundamental biological process by which a parent cell divides into two or more daughter cells. This process is essential for growth, repair, and reproduction in all living organisms. There are two main types of cell division: mitosis and meiosis.

Mitosis is a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth. This process occurs in somatic cells, which are all body cells except the gametes. Mitosis is crucial for the development of an organism from a single fertilized egg, as well as for replacing damaged or old cells throughout an organism's life. The stages of mitosis include prophase, metaphase, anaphase, and telophase, each involving specific chromosomal movements and cellular rearrangements.

Meiosis, on the other hand, is a specialized type of cell division that occurs in reproductive cells (germ cells) to produce gametes (sperm and egg cells). Meiosis involves two successive nuclear divisions that result in four daughter cells, each with half the number of chromosomes as the parent cell. This reduction in chromosome number is vital for sexual reproduction, ensuring that the offspring inherit a complete set of chromosomes from both parents. Meiosis consists of two rounds of division, meiosis I and meiosis II, which further diversify genetic material through processes like crossing over.

The cell cycle, which includes interphase (growth and DNA replication) and the M phase (mitosis or meiosis), governs the timing and execution of cell division. This carefully regulated cycle ensures that DNA is accurately replicated and distributed to daughter cells, maintaining genetic integrity. Errors in cell division can lead to various genetic disorders and diseases, including cancer.