An image of a newt lung cell stained with fluorescent dyes undergoing mitosis

What Is Mitosis?
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Why Do Cells Divide?
You grew from a zygote (a fertilized egg) into an organism with trillions of specialized cells. Mitosis is the process that enabled you to grow and develop after that fateful meeting of egg and sperm became ‘you’. That is the human life cycle.

Article Summary: In order for organisms to grow, develop and maintain life, cells must divide. Cellular division involves the basic stages of interphase, nuclear division (mitosis) and cytokinesis. Here's a summary.
Mitotic Cell Division of Eukaryotes

Major Events of Eukaryotic Cell Division
There are two major phases to the cell cycle:
  • Interphase (3 substages)
  • Mitosis (4 substages)

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Cell Replacement
Cells must divide in order for an organism to grow and develop, but cell division is also required for tissue repair, maintenance, cell turnover and replacement. 
​Many tissues in your body are composed of cells that have a high turn-over rate. 

Think of your skin. The epidermis, or top layer, is composed of dead cells that are constantly being sloughed off and replaced from below by cells of the dermis (the living cells in the layer of skin below the epidermis). If cells of the dermis were not constantly dividing to replace dead cells, your skin would eventually wear out.

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Continued ... 
Steps of Mitosis
Go to PAGE 2 >
This is also true of the mucous membranes of your body; the moist areas of the GI tract and urogenital tract that are the interface between your internal systems with the outside world.

Eukaryotic Cell Cycle
During the cell cycle, somatic cells (non-reproductive cells) of eukaryotic organisms grow and divide. It is the process of a single cell (parent cell) splitting into two identical ‘daughter cells’. The daughter cells are clones of the parent, and have the same number of chromosomes as the parent cell.

Cell division over 42 hours. Cells  imaged in culture using phase contrast time-lapse microscopy.
Cell division over 42 hours. Cells  imaged  culture using phase contrast time-lapse microscopy.

See Page 2 for details on the steps of mitosis!
​Page last updated: 10/2015
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Endomembrane System of a Eukaryotic Cell, Mariana Ruiz
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