Cell Division: Mitosis and Meiosis PDF

# Cell Division ## Mitosis ### What is Mitosis? Mitosis divides a eukaryotic cell's chromosomes into two identical daughter cells, wherein mitotic cell division produces the cells needed for growth, development, and tissue repair. ### Stages of Mitosis - Interphase - Prophase - Metaphase - An...

# Cell Division ## Mitosis ### What is Mitosis? Mitosis divides a eukaryotic cell's chromosomes into two identical daughter cells, wherein mitotic cell division produces the cells needed for growth, development, and tissue repair. ### Stages of Mitosis - Interphase - Prophase - Metaphase - Anaphase - Telophase - Cytokinesis #### Interphase During interphase, the cell undergoes normal growth processes while also preparing for cell division. In order for a cell to move from interphase into the mitotic phase, many internal and external conditions must be met. #### Prophase Prophase is the stage of chromosome replication. The chromosomes condense and the spindle forms; the nucleus disassembles, the nuclear envelope breaks up, and the spindle fibers attach to the chromosomes. #### Metaphase Metaphase is the step in which the chromosomes formed in prophase move to the middle of the cell. These chromosomes line up along the equator of the cell. #### Anaphase Anaphase is where the chromosomes separate and move to opposite sides of the cell. Shortening spindle fibers separate the chromosomes. #### Telophase Telophase is where the nucleus reforms and a membrane appears between each mass of chromosomes. This newly formed membrane divides the cytoplasm. Once this is completed, the two separate cells repeat the process. #### Cytokinesis Cytokinesis is the final stage of cell division, during which the cytoplasm of the cell is divided into two daughter cells. In animal cells, this process is accomplished by a cleavage furrow, which pinches the cell membrane inward until the cell is divided into two. ## Meiosis ### What is Meiosis? Meiosis is a type of cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes (the sex cells, or egg and sperm). ### Stages of Meiosis - Prophase I - Metaphase I - Anaphase I - Telophase I - Cytokinesis - Prophase II - Metaphase II - Anaphase II - Telophase II - Cytokinesis #### Prophase I - Chromosomes condense and become visible. - Crossing over occurs (exchange of genetic materials). - Spindle forms. - Nuclear envelope breaks down. #### Metaphase I Paired homologous chromosomes line up along the equator of the cell. #### Anaphase I Homologous chromosomes separate to opposite poles of the cell. #### Telophase I Nuclear envelopes form around chromosomes, which may temporarily decondense. #### Prophase II - Spindle forms. - Nuclear envelope breaks down. #### Metaphase II Chromosomes line up along the equator of the cell. #### Anaphase II Centromeres split as sister chromatids separate to opposite poles of the cell. #### Telophase II Nuclear envelopes assemble around daughter nuclei. Chromosomes decondense. Spindle disappears. Cytokinesis divides cells.