Mitosis conserves chromosome number by precisely duplicating each chromosome and then equally segregating the resulting identical sister chromatids into two separate daughter cells.
Here's a detailed breakdown of how this happens:
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Chromosome Duplication (S Phase): Before mitosis begins, during the S phase of the cell cycle, each chromosome is duplicated. This process creates two identical copies called sister chromatids, which remain attached to each other at a region called the centromere.
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Prophase and Metaphase: As mitosis begins (prophase), the chromosomes condense and become visible. During metaphase, the sister chromatids line up along the middle of the cell (the metaphase plate).
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Anaphase: Sister Chromatid Separation: The key to chromosome number conservation occurs during anaphase. Here, the sister chromatids are pulled apart from each other by the spindle fibers. Each sister chromatid now becomes an individual chromosome.
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Telophase: Equal Distribution: These newly separated chromosomes are then pulled to opposite ends of the cell. A nuclear membrane forms around each set of chromosomes.
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Cytokinesis: Cell Division: Finally, cytokinesis occurs, dividing the cell into two separate daughter cells. Because each daughter cell received a complete set of the original chromosomes, the chromosome number is maintained.
In essence, mitosis ensures that each new cell receives an identical and complete set of chromosomes, maintaining the genetic integrity and chromosome number of the parent cell. Therefore, if the parent cell had 46 chromosomes, each daughter cell will also have 46 chromosomes.
