Mitosis cell division | Part- 1

Mitosis: Definition, Features, Stages, Functions, and Significance

Mitosis is a fundamental process of cell division that ensures the equal distribution of genetic material into two genetically identical daughter cells. It occurs in somatic (non-reproductive) cells and plays a vital role in growth, repair, and asexual reproduction in multicellular organisms.

What is Mitosis?

Mitosis is a form of cell division where one parent cell splits to form two daughter cells, each carrying an identical number and type of chromosomes as the original cell. It maintains genetic continuity and is essential for tissue development and regeneration. Unlike meiosis, mitosis does not result in genetic variation.

Features of Mitosis

• Occurs in somatic cells of plants and animals.
• One parent cell produces two identical daughter cells.
• Keeps the chromosome count unchanged (diploid to diploid).
• Genetic material remains unchanged as no recombination or crossing over happens.
• Only one round of nuclear division takes place.

Stages of Mitosis

Mitosis is a continuous process but is conventionally divided into four major stages:

1. Prophase

The chromatin fibers coil tightly to form distinct chromosomes, each made up of a pair of identical sister chromatids. The nuclear membrane breaks down, and spindle fibers begin to form from the centrosomes.

2. Metaphase

Chromosomes align at the cell’s equatorial plane (metaphase plate), and spindle fibers attach to the centromeres via kinetochores.

3. Anaphase

Sister chromatids separate and move to opposite poles of the cell as the spindle fibers shorten. At this point, each separated chromatid is regarded as a separate chromosome.

4. Telophase

Chromosomes begin to de-condense into chromatin. Nuclear envelopes re-form around each set of chromosomes, resulting in the formation of two nuclei.

Cytokinesis typically occurs after telophase, dividing the cytoplasm and resulting in the formation of two distinct daughter cells.

Functions of Mitosis

• Enables growth by increasing the number of cells.
• Helps in the repair and replacement of damaged or dead cells.
• Responsible for asexual reproduction in unicellular and some multicellular organisms.
• Ensures genetic consistency by keeping the chromosome number unchanged.

Significance of Mitosis

• Guarantees that the daughter cells have the same genetic makeup as the original parent cell.
• Crucial for embryonic development and cell turnover.
• Plays a vital role in healing wounds and regenerating tissues.
• Maintains the proper function of tissues and organs in multicellular organisms.