Explain the difference between mitosis and meiosis.
Mitosis and meiosis are two different processes involved in cell division, and they have distinct differences. Here's an explanation for each:
1. Mitosis:
Mitosis is a form of cell division that leads to the production of two identical daughter cells, each with the same number of chromosomes as the parent cell. It has several key steps:
- Interphase: The cell prepares for division by growing, replicating its DNA, and synthesizing proteins.
- Prophase: The nuclear membrane dissolves, and the chromosomes condense, becoming visible under a microscope.
- Metaphase: Chromosomes align in the center of the cell.
- Anaphase: Sister chromatids separate and move to opposite ends of the cell.
- Telophase: New nuclear membranes form around the separated chromosomes, and the cell begins to divide.
- Cytokinesis: The cytoplasm divides, resulting in two genetically identical daughter cells.
2. Meiosis:
Meiosis is a specialized form of cell division that occurs in reproductive cells (gametes) and leads to the production of four non-identical daughter cells, each with half the number of chromosomes as the parent cell (haploid). It involves two rounds of division: meiosis I and meiosis II. Here's a simplified explanation:
- Interphase: Cells prepare for division, similar to mitosis.
- Meiosis I:
- Prophase I: Chromosomes condense and pair with their homologous partner, forming tetrads. Crossing over between genetic material occurs.
- Metaphase I: Tetrads align at the cell's equator.
- Anaphase I: Homologous chromosomes separate and move to opposite poles.
- Telophase I: Two haploid cells form, each with duplicated sister chromatids.
- Meiosis II:
- Prophase II, metaphase II, anaphase II, and telophase II, resemble the respective phases in mitosis.
- At the end of meiosis II, four haploid cells are produced, each genetically distinct from the others due to crossing over and random assortment of chromosomes.
To summarize, mitosis results in two genetically identical diploid cells, while meiosis produces four genetically distinct haploid cells, each with half the number of chromosomes as the parent cell.