Mitosis is nuclear division plus cytokinesis, and produces two identical daughter cells during prophase, prometaphase, metaphase, anaphase, and telophase. Interphase is often included in discussions of mitosis, but  interphase is technically not part of mitosis, but rather encompasses  stages G1, S, and G2 of the cell cycle.
Interphase & mitosisInterphase:
The cell is engaged in metabolic activity and performing its prepare for  mitosis (the next four phases that lead up to and include nuclear  division). Chromosomes are not clearly discerned in the nucleus,  although a dark spot called the nucleolus may be visible. The cell may  contain a pair of centrioles (or microtubule organizing centers in  plants) both of which are organizational sites for microtubules.
Prophase:Chromatin in the nucleus begins to condense and becomes visible in the light   microscope as chromosomes. The nucleolus disappears. Centrioles begin moving   to opposite ends of the cell and fibers extend from the centromeres. Some fibers   cross the cell to form the mitotic spindle. 
Metaphase: Spindle fibers align the chromosomes along the middle of the cell nucleus. This     line is referred to as the metaphase plate. This organization helps to ensure     that in the next phase, when the chromosomes are separated, each new nucleus     will receive one copy of each chromosome.
Anaphase:The paired chromosomes separate at the kinetochores and move to opposite sides     of the cell. Motion results from a combination of kinetochore movement along     the spindle microtubules and through the physical interaction of polar microtubules. 
Telophase:Chromatids arrive at opposite poles of cell, and new membranes form around the     daughter nuclei. The chromosomes disperse and are no longer visible under     the light microscope. The spindle fibers disperse, and cytokinesis or the     partitioning of the cell may also begin during this stage.  
Cytokinesis: 
In animal cells, cytokinesis results when a fiber ring composed of a protein     called actin around the center of the cell contracts pinching the cell into     two daughter cells, each with one nucleus. In plant cells, the rigid wall     requires that a cell plate be synthesized between the two daughter cells. 
   
No comments:
Post a Comment