Description

Animal cell Division Mitosis is the process by which a single animal cell divides to produce two genetically identical daughter cells. It is a crucial part of cell division for growth, repair, and maintenance of an organism. Mitosis occurs in somatic cells (non-reproductive cells) and ensures that each daughter cell receives an exact copy of the parent cell’s DNA.

Stages of Mitosis in Animal Cells:

1. Interphase (Preparation Phase, Not Part of Mitosis)

   • The cell grows and replicates its DNA.
   • Chromosomes are not yet visible; they exist as chromatin.

2. Prophase

   • Chromatin condenses into visible chromosomes (each consisting of two sister chromatids).
   • Centrioles (in animal cells) move to opposite poles.
   • The mitotic spindle forms, and the nuclear membrane begins to break down.

3. Metaphase

   • Chromosomes align at the cell’s equatorial plane (metaphase plate).
   • Spindle fibers attach to the centromere of each chromosome.

4. Anaphase

   • Sister chromatids separate and move toward opposite poles.
   • Spindle fibers shorten, pulling chromatids apart.

5. Telophase

   • Chromatids reach the poles and decondense into chromatin.
   • The nuclear membrane re-forms around each set of chromosomes.
   • The spindle fibers break down.

6. Cytokinesis (Cytoplasmic Division)

   • The cell membrane pinches in (cleavage furrow) and divides the cytoplasm.
   • Two identical daughter cells are formed.

Key Points:

• Mitosis ensures genetic continuity.
• Animal cells use centrioles to help organize the spindle fibers.
• The entire process is asexual reproduction at the cellular level.
• Mitosis is different from meiosis, which produces gametes (sperm and egg) with half the chromosome number.