Mitosis and meiosis are both processes of cell division, but they serve different purposes and involve distinct processes and outcomes. Here is a comparison of the two:
Purpose
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Mitosis: The primary purpose of mitosis is to produce two genetically identical daughter cells for growth, tissue repair, and asexual reproduction. It allows for the maintenance of the same chromosome number in the daughter cells as in the parent cell.
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Meiosis: The main purpose of meiosis is to produce gametes (sperm and eggs) for sexual reproduction. Meiosis introduces genetic diversity through recombination and reduces the chromosome number by half, resulting in haploid cells.
Process
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Mitosis:
- Phases: Includes prophase, metaphase, anaphase, and telophase.
- DNA Replication: Occurs during interphase before mitosis begins, resulting in two sister chromatids for each chromosome.
- Division of Genetic Material: Each chromosome is replicated and evenly distributed to two daughter cells.
- Number of Divisions: Involves a single round of division.
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Meiosis:
- Phases: Consists of two rounds of division: meiosis I (reduction division) and meiosis II (equational division).
- DNA Replication: Also occurs during interphase before meiosis begins, but it results in homologous chromosomes pairing.
- Homologous Chromosome Alignment and Recombination: During prophase I, homologous chromosomes are paired, and crossing over can occur, leading to genetic recombination.
- Number of Divisions: Involves two rounds of division (meiosis I and meiosis II), resulting in four haploid daughter cells.
Outcome
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Mitosis: Results in two diploid daughter cells that are genetically identical to each other and to the parent cell. The chromosome number remains constant (e.g., human cells maintain 46 chromosomes).
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Meiosis: Results in four non-identical haploid daughter cells, each with half the number of chromosomes of the parent cell (e.g., human gametes have 23 chromosomes). The genetic variation is introduced through crossing over and independent assortment of chromosomes.
Summary
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Mitosis is for growth, repair, and asexual reproduction, resulting in two identical diploid cells. It involves one division and maintains chromosome number.
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Meiosis is for producing gametes in sexual reproduction, resulting in four genetically diverse haploid cells. It involves two divisions and reduces chromosome number by half.
Understanding these differences is crucial in fields such as genetics, biology, and medicine, particularly in relation to inheritance, evolution, and disease.