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# Cell Division - Mitosis **Chapter 6** Mitosis is a continuous process, but it's possible to distinguish the following phases: * **Prophase:** During this phase, the chromatin network shortens and thickens, becoming visible chromosomes. The DNA has replicated, creating chromatin/chromosomes ea...

# Cell Division - Mitosis **Chapter 6** Mitosis is a continuous process, but it's possible to distinguish the following phases: * **Prophase:** During this phase, the chromatin network shortens and thickens, becoming visible chromosomes. The DNA has replicated, creating chromatin/chromosomes each consisting of two identical DNA molecules. The nuclear membrane disappears, the nucleolus disintegrates, the nuclear plasm changes, and cell organelles move away from the nucleus. The centrioles duplicate and move to opposite poles. Cytoplasmic threads (spindle fibers) appear between the centrioles. * **Metaphase:** The chromosomes arrange themselves on the equatorial level of the cell. The centromere, connecting the two chromatids and lying on one spindle thread. * **Anaphase:** The spindle threads shrink, splitting the centromere in two and separating the chromatids. These now separate chromatids now called daughter chromosomes, move to opposite poles. * **Telophase:** Daughter chromosomes, join to form a chromatin network. The DNA/chromatin/ chromosomes of the two cells are absolutely identical. The nuclear membrane as well as the nucleolus reappears. An invagination forms in the middle of the cell, resulting in two identical daughter cells. **Purpose of Mitosis:** * **Growth**: responsible for the growth of the organism * **Replacement**: replaces damaged or worn tissues in cells. * **Reproduction**: used in reproduction for unicellular organisms. **Additional Information:** * The division of the nucleus is called karyokinesis and the division of the cytoplasm is called cytokinesis. * Mutations can occur when a random mistake or change occurs during DNA replication. Some mutations are deadly while others can be beneficial (contributing to the development of new species). * Mitosis results in two identical daughter cells. **Diagram Description:** A microscopic image, likely a photomicrograph, shows cells undergoing various stages of mitosis. The cells and their internal structures appear to be stained or highlighted in some way to enhance visibility. Magnification is stated to be approximately x500. The image is from a root tip. **Diagram Figure:** A simple representation diagram is also present showing 2n (diploid number of chromosomes) cells replicating into 2n cells.