Jakautumisvaiheet

Jakautumisvaiheet, known in English as "division phases," refers to the stages of cell division in biology. This process is fundamental to the growth, repair, and reproduction of all living organisms. The primary types of cell division are mitosis and meiosis.

Mitosis is a process that results in two daughter cells that are genetically identical to the parent cell. It is crucial for asexual reproduction and for increasing the number of cells in multicellular organisms. The phases of mitosis include prophase, metaphase, anaphase, and telophase. During prophase, chromosomes condense and become visible. In metaphase, they align at the cell's equator. Anaphase sees sister chromatids separating and moving to opposite poles. Finally, telophase involves the formation of new nuclear envelopes around the separated chromosomes, followed by cytokinesis, the division of the cytoplasm, to complete the formation of two distinct 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. This process is essential for sexual reproduction, as it produces gametes (sperm and egg cells). Meiosis involves two successive divisions, meiosis I and meiosis II. Meiosis I includes prophase I, metaphase I, anaphase I, and telophase I, where homologous chromosomes pair up and then separate. Meiosis II is similar to mitosis, with prophase II, metaphase II, anaphase II, and telophase II, resulting in the separation of sister chromatids. The genetic variation introduced during meiosis through crossing over and independent assortment is vital for evolution.