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mitosis
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GPT-4o mini
Mitosis is a process of cell division that results in two genetically identical daughter cells from a single parent cell. It is a crucial mechanism for growth, repair, and asexual reproduction in multicellular organisms. Mitosis can be divided into several phases, each with specific events that lead to the separation of duplicated chromosomes. The main phases of mitosis are:
1. **Prophase**: The chromatin condenses into visible chromosomes, each consisting of two sister chromatids joined at the centromere. The nuclear envelope begins to break down, and the mitotic spindle, made of microtubules, starts to form and extends from the centrosomes.
2. **Metaphase**: The chromosomes align along the metaphase plate (the cell's equator) due to the pulling forces of the spindle fibers attached to the centromeres. This alignment ensures that each daughter cell will receive one copy of each chromosome.
3. **Anaphase**: The sister chromatids are pulled apart by the spindle fibers and move toward opposite poles of the cell. This separation ensures that each daughter cell will have the correct number of chromosomes.
4. **Telophase**: The chromatids reach the poles and begin to decondense back into chromatin. The nuclear envelope re-forms around each set of chromosomes, leading to the formation of two distinct nuclei.
5. **Cytokinesis**: Although technically not a phase of mitosis itself, cytokinesis often occurs concurrently with telophase. This process involves the division of the cytoplasm, resulting in two separate daughter cells. In animal cells, this is accomplished through the formation of a cleavage furrow, while in plant cells, a cell plate is formed.
Mitosis is essential for growth and tissue repair, and errors in this process can lead to conditions such as cancer, where uncontrolled cell division occurs.
1. **Prophase**: The chromatin condenses into visible chromosomes, each consisting of two sister chromatids joined at the centromere. The nuclear envelope begins to break down, and the mitotic spindle, made of microtubules, starts to form and extends from the centrosomes.
2. **Metaphase**: The chromosomes align along the metaphase plate (the cell's equator) due to the pulling forces of the spindle fibers attached to the centromeres. This alignment ensures that each daughter cell will receive one copy of each chromosome.
3. **Anaphase**: The sister chromatids are pulled apart by the spindle fibers and move toward opposite poles of the cell. This separation ensures that each daughter cell will have the correct number of chromosomes.
4. **Telophase**: The chromatids reach the poles and begin to decondense back into chromatin. The nuclear envelope re-forms around each set of chromosomes, leading to the formation of two distinct nuclei.
5. **Cytokinesis**: Although technically not a phase of mitosis itself, cytokinesis often occurs concurrently with telophase. This process involves the division of the cytoplasm, resulting in two separate daughter cells. In animal cells, this is accomplished through the formation of a cleavage furrow, while in plant cells, a cell plate is formed.
Mitosis is essential for growth and tissue repair, and errors in this process can lead to conditions such as cancer, where uncontrolled cell division occurs.