Mitosis - The Cell's Copy Machine (Extended)

 

What Is Mitosis?

Mitosis is a type of cell division where one parent cell splits into two genetically identical daughter cells. It ensures that each new cell has the same number of chromosomes as the original cell.

Think of mitosis like photocopying a document – the two new cells (copies) are identical to the original

 

Key Features of Mitosis

Feature	Explanation
Genetically Identical Cells	Daughter cells are exact copies of the parent cell (same DNA).
Chromosome Number	The number of chromosomes stays the same in the new cells.
Purpose	Used for growth, repair, replacement of cells, and asexual reproduction.

 

Steps in Mitosis

Although details of the stages aren't required, here's a simple summary to understand the process:

1. Replication of Chromosomes

   • Before mitosis starts, the chromosomes in the cell replicate, creating identical copies (called sister chromatids).

   • Analogy: Imagine copying a stack of pages. You’ll now have two identical stacks!

2. Chromosome Separation

   • During mitosis, the sister chromatids first line up along the center to be split.

   • The cell then separates and the chromosomes are pulled to opposite sides of the cell.

   • Analogy: Think of tearing the stack of pages in half to distribute them equally.

3. Two Identical Cells

   • The cell divides into two daughter cells, each with the same number and type of chromosomes as the parent cell.

 

 

Why Is Mitosis Important?

Function	Explanation
Growth	Helps multicellular organisms grow by adding more cells.
Repair	Replaces damaged cells (e.g., healing a cut).
Replacement	Replaces old or worn-out cells (e.g., skin cells).
Asexual Reproduction	Used by some organisms (like bacteria) to reproduce without needing a mate.

 

Stem Cells and Mitosis

• Stem cells are unspecialised cells that divide by mitosis.
• These cells can then specialise into different types of cells (e.g., muscle cells, nerve cells).

Term	Definition
Unspecialised	Not yet assigned a specific function.
Specialised	Have a specific function (e.g., skin cell for protection).

 

Key Facts to Remember

• Exact Replication of Chromosomes:
  Before mitosis, chromosomes replicate to ensure the daughter cells have the same genetic material.

• Maintaining Chromosome Number:
  Mitosis keeps the chromosome number constant, ensuring no loss or duplication.

  Example in humans:

  • Parent cell has 46 chromosomes.
  • After mitosis, each daughter cell also has 46 chromosomes.