Cell Division: Mitosis and Meiosis

Study Notes

Definition: Process of cell division that results in two daughter cells with the same number of chromosomes as the parent cell.
Purpose: Allows for growth, repair, and replacement of cells in multicellular organisms.
Stages:
1. Interphase: Cell grows, replicates DNA, and prepares for cell division.
2. Prophase: Chromatin condenses, nuclear envelope breaks down, and centrioles move to opposite poles.
3. Metaphase: Chromosomes line up at the center of the cell, attached to the spindle fibers.
4. Anaphase: Sister chromatids separate and move to opposite poles.
5. Telophase: Nuclear envelope reforms, and chromatin uncondenses.
6. Cytokinesis: Cytoplasm divides, and the cell splits into two daughter cells.

Definition: Process of cell division that results in four non-identical daughter cells with half the number of chromosomes as the parent cell.
Purpose: Allows for genetic variation and the production of gametes (sperm and egg cells) in sexually reproducing organisms.
Stages:
1. Interphase: Cell grows, replicates DNA, and prepares for cell division.
2. Prophase I: Chromatin condenses, nuclear envelope breaks down, and homologous chromosomes pair up.
3. Metaphase I: Paired chromosomes line up at the center of the cell, attached to the spindle fibers.
4. Anaphase I: Homologous chromosomes separate and move to opposite poles.
5. Telophase I: Nuclear envelope reforms, and chromatin uncondenses.
6. Prophase II: Chromosomes condense, nuclear envelope breaks down, and centrioles move to opposite poles.
7. Metaphase II: Chromosomes line up at the center of the cell, attached to the spindle fibers.
8. Anaphase II: Sister chromatids separate and move to opposite poles.
9. Telophase II: Nuclear envelope reforms, and chromatin uncondenses.
10. Cytokinesis: Cytoplasm divides, and the cell splits into four daughter cells.

Number of daughter cells: Mitosis produces 2 daughter cells, while meiosis produces 4 daughter cells.
Number of chromosomes: Mitosis results in daughter cells with the same number of chromosomes as the parent cell, while meiosis results in daughter cells with half the number of chromosomes.
Genetic variation: Meiosis introduces genetic variation through crossing over and independent assortment, while mitosis does not.