Interphase (Not technically part of mitosis, but essential preparation)
* G1 Phase: The cell grows and synthesizes proteins and organelles.
* S Phase: DNA replication occurs, creating two identical copies of each chromosome.
* G2 Phase: The cell continues to grow, synthesizes more proteins, and prepares for mitosis.
Mitosis (The division of the nucleus)
1. Prophase:
* Chromatin condenses into visible chromosomes (each with two identical sister chromatids).
* The nuclear envelope breaks down.
* The spindle fibers form from the centrosomes (centrioles in animal cells, but plant cells lack centrioles) and begin to migrate toward opposite poles of the cell.
2. Metaphase:
* The chromosomes line up at the equator (metaphase plate) of the cell, attached to the spindle fibers by their centromeres.
3. Anaphase:
* The centromeres of each chromosome separate, and the sister chromatids are pulled apart by the spindle fibers towards opposite poles of the cell.
* The cell elongates.
4. Telophase:
* The chromosomes reach the poles of the cell and begin to uncoil (decondense).
* The nuclear envelope reforms around each set of chromosomes, creating two new nuclei.
* The spindle fibers disappear.
Cytokinesis (The division of the cytoplasm)
* Cell Plate Formation: A cell plate forms between the two newly formed nuclei. This cell plate grows outward from the center of the cell, eventually fusing with the existing cell wall.
* Cell Wall Formation: New cell walls are synthesized along the cell plate, creating a new cell wall that divides the two daughter cells.
Key Differences from Animal Cell Mitosis
* Centrioles: Plant cells lack centrioles, so the spindle fibers form from microtubule organizing centers (MTOCs) located in the cytoplasm.
* Cell Plate Formation: Instead of a cleavage furrow (like in animal cells), plant cells divide by forming a cell plate, which eventually becomes the new cell wall.
Let me know if you'd like more detail on any specific stage!
