What is Mitosis? What are the Stages of Mitosis?

The main purpose of mitosis is to ensure "genetic continuity." The number of chromosomes (46 in humans) never changes as a result of division. While there is initially 1 cell, 2 cells with exactly the same genetic code are formed at the end of the process. While it provides growth, development, and tissue repair in multicellular organisms (humans); it directly enables "reproduction (proliferation)" in single-celled organisms like amoebas and bacteria.

Mitosis takes place in 4 main stages as nuclear division, following the preparation phase (Interphase): 1. **Prophase:** The nuclear membrane dissolves, chromatin threads thicken and turn into distinct chromosomes. 2. **Metaphase:** Chromosomes line up in a single row right in the middle of the cell (equatorial plane). (This is the stage where chromosomes are seen most clearly under a microscope). 3. **Anaphase:** Sister chromatids separate from each other and are pulled towards opposite poles of the cell. 4. **Telophase:** A nuclear membrane reforms around the chromatids drawn to the poles. Then, with cytoplasmic division (Cytokinesis), the cell pinches in the middle and completely separates into two.

In a healthy body, mitosis is under very strict genetic control; the cell knows when to divide and when to stop (Apoptosis/Cell death). However, if the cell's DNA mutates, it loses this "stop" signal. The cell begins to undergo mitosis uncontrollably, continuously, and wildly. These uncontrolled cell clusters (masses) are called "Cancer / Tumors."