Cell Biology
Mitosis is a type of cell division resulting in the creation of two genetically identical daughter cells. This process occurs in most eukaryotic cells and is essential for growth and development.
Mitosis is divided into four stages: prophase, metaphase, anaphase, and telophase, followed by cytokinesis. In prophase, chromatin condenses into sister chromatids, the nuclear envelope starts breaking down, the nucleolus disappears, and the spindle apparatus begins assembly. In metaphase, sister chromatids line up along the metaphase plate. In anaphase, sister chromatids are pulled apart. In telophase, spindle fibers disappear and the nuclear envelope reappears before the parent cell fully splits into two daughter cells through cytokinesis.
Lesson Outline
<ul> <li>Introduction to Mitosis <ul> <li>Creation of two identical daughter cells</li> <li>Occurs in most eukaryotic cells</li> <li>Germ cells undergo meiosis instead</li> </ul> </li> <li>Cell Cycle <ul> <li>Interphase <ul> <li>Cell growth and DNA replication</li> <li>Chromatin is loosely packed</li> <li>Nucleolus is present and produces ribosomes</li> </ul> </li> <li>Mitotic Phase <ul> <li>Includes mitosis and cytokinesis</li> </ul> </li> </ul> </li> <li>Stages of Mitosis <ul> <li>Prophase <ul> <li>Chromatin condenses into sister chromatids</li> <li>Nuclear envelope breaks down</li> <li>Nucleolus disappears</li> <li>Centrosomes move to opposite ends of the cell</li> <li>Spindle fibers extend from centrioles</li> <li>Three types of spindle fibers: polar, astral, and kinetochore microtubules</li> </ul> </li> <li>Metaphase <ul> <li>Sister chromatids line up at the metaphase plate</li> </ul> </li> <li>Anaphase <ul> <li>Sister chromatids are pulled apart to opposite poles</li> </ul> </li> <li>Telophase <ul> <li>Spindle fibers disappear</li> <li>Nuclear envelope forms again</li> </ul> </li> </ul> </li> <li>Cytokinesis <ul> <li>Separates cytoplasm and organelles into 2 daughter cells</li> <li>Actomyosin ring pinches down on the cell to create a cleavage furrow</li> </ul> </li> </ul>
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FAQs
Mitosis is a process of cell division that occurs in eukaryotic cells, producing two daughter cells with an identical set of chromosomes. This results in the formation of genetically identical cells with equal distribution of genetic material. Mitosis progresses through distinct phases - prophase, metaphase, anaphase, and telophase - ensuring proper DNA replication, chromosome segregation, and the division of cellular components.
Several essential structures of eukaryotic cells are involved in mitosis, including chromatin, the nucleolus, the nuclear envelope, centrosomes, spindle fibers, and the cell membrane. The chromatin condenses into chromosomes and separates during mitosis. The nucleolus disappears during the early mitotic phase, indicating that the cell is ready to divide. The nuclear envelope fragments in prophase and reforms around daughter nuclei in telophase, while the cell membrane undergoes dynamic changes, finally dividing in cytokinesis to form two separate cells.
Chromatin, a complex of DNA and proteins, condenses into visible chromosomes during the mitotic phase. Each replicated chromosome consists of two sister chromatids joined at their centromeres. As the nuclear envelope breaks down during prophase, the chromosomes align at the cell equator during metaphase. In anaphase, the chromatids separate and migrate towards the cell poles, becoming individual chromosomes in two new nuclei. The nuclear envelope reassembles around these separated chromosomes during telophase, ultimately producing two distinct daughter nuclei.
Cytokinesis is the final stage of cell division that physically separates the cytoplasm and other cellular components into two daughter cells. For animal cells, the cell membrane undergoes a process called cleavage, in which a contractile ring composed of actin and myosin filaments pinches the membrane, forming a cleavage furrow. This furrow gradually deepens until the membrane fuses, resulting in the separation of the two cells. In plant cells, cytokinesis occurs with the formation of a cell plate, which eventually develops into a cell wall, dividing the cell into two distinct daughter cells.
