1. Interphase: This is the stage where the cell grows and copies its DNA. It's often not considered part of mitosis, but it's essential for the process to occur. Interphase is divided into three subphases:
* G1 (Gap 1): Cell grows and performs its normal functions.
* S (Synthesis): DNA replication occurs, resulting in two identical copies of each chromosome.
* G2 (Gap 2): Cell continues to grow and prepares for mitosis.
2. Prophase:
* Chromatin Condenses: The DNA, which was previously loose and thread-like, condenses into visible chromosomes.
* Nuclear Envelope Breaks Down: The membrane surrounding the nucleus disintegrates.
* Spindle Fibers Form: Microtubules start to form the spindle apparatus, which will be used to separate the chromosomes.
3. Metaphase:
* Chromosomes Align: The chromosomes line up along the center of the cell, forming the metaphase plate.
* Spindle Fibers Attach: Spindle fibers from opposite poles of the cell attach to the centromere of each chromosome.
4. Anaphase:
* Sister Chromatids Separate: The centromere of each chromosome splits, and the sister chromatids (identical copies of a chromosome) are pulled apart by the spindle fibers.
* Chromatids Move to Poles: Each set of chromatids moves toward opposite poles of the cell.
5. Telophase:
* Chromosomes Arrive at Poles: The separated chromosomes reach the opposite poles of the cell.
* Nuclear Envelope Reforms: A new nuclear envelope forms around each set of chromosomes, creating two new nuclei.
* Chromosomes Uncoil: The chromosomes unwind and become less visible.
* Cytokinesis Begins: The division of the cytoplasm starts, leading to the formation of two daughter cells.
6. Cytokinesis:
* Cytoplasm Divides: The cytoplasm of the cell is divided, separating the two new nuclei and creating two separate daughter cells. In animal cells, a cleavage furrow forms, while in plant cells, a cell plate forms.
Key Point: The result of mitosis is two genetically identical daughter cells from a single parent cell. This process is crucial for growth, repair, and asexual reproduction in many organisms.
