Mitosis and meiosis are two types of cell division that serve different purposes in organisms. Here are the key differences between them:
1. Purpose:
- Mitosis: Primarily for growth, repair, and asexual reproduction. It produces identical daughter cells for tissue maintenance and development.
- Meiosis: Primarily for sexual reproduction. It produces gametes (sperm and eggs) and ensures genetic diversity through recombination and independent assortment.
2. Number of Divisions:
- Mitosis: Involves one round of cell division, resulting in two daughter cells.
- Meiosis: Involves two rounds of cell division (meiosis I and meiosis II), resulting in four daughter cells.
3. Genetic Composition:
- Mitosis: Daughter cells are genetically identical to the parent cell and to each other (clones), preserving the diploid (2n) chromosome number.
- Meiosis: Daughter cells are genetically diverse and have half the chromosome number of the parent cell (haploid, n). This is important for maintaining chromosome number across generations when gametes fuse during fertilization.
4. Chromosome Number:
- Mitosis: Starts with a diploid cell (2n) and ends with two diploid daughter cells.
- Meiosis: Starts with a diploid cell (2n) and ends with four haploid cells (n).
5. Stages:
- Mitosis: Consists of prophase, metaphase, anaphase, and telophase, followed by cytokinesis.
- Meiosis: Consists of two stages: meiosis I (which includes prophase I, metaphase I, anaphase I, telophase I, and cytokinesis) and meiosis II (which includes prophase II, metaphase II, anaphase II, telophase II, and cytokinesis).
6. Genetic Recombination:
- Mitosis: No genetic recombination or crossing over occurs.
- Meiosis: Crossing over (exchange of genetic material) occurs during prophase I, leading to genetic variation in the resulting gametes.
In summary, mitosis is responsible for the growth and repair of tissues without changing the genetic content, while meiosis is crucial for sexual reproduction and generating genetic diversity in offspring.