sejtosztódásainak

Sejtosztódásának, or cell division, is a fundamental biological process by which a parent cell divides into two or more daughter cells. This process is crucial 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 is essential for asexual reproduction, growth from a single fertilized egg to a complex organism, and the replacement of worn-out or damaged cells in multicellular organisms. Mitosis involves a series of stages: prophase, metaphase, anaphase, and telophase, each characterized by specific events related to chromosome condensation, alignment, separation, and the formation of new nuclei. Cytokinesis, the division of the cytoplasm, usually follows mitosis, completing the formation of two distinct daughter cells.

Meiosis, on the other hand, is a specialized type of cell division that reduces the chromosome number by half, creating four haploid cells, each genetically distinct from the parent cell and from each other. Meiosis is essential for sexual reproduction, producing gametes (sperm and egg cells) in animals and spores in plants and fungi. It involves two rounds of division, meiosis I and meiosis II. Meiosis I separates homologous chromosomes, while meiosis II separates sister chromatids. This process introduces genetic variation through crossing over, where homologous chromosomes exchange segments, and independent assortment, where homologous chromosome pairs align randomly.