Lecture on Mitosis

Introduction

• Mitosis is a type of cell division essential for growth and repair in the body.
• Common experiences showing mitosis include healing cuts, growing nails, and increased body size over time.

Importance of Mitosis

• Growth: Allows growth by producing more cells.
• Repair: Helps repair damaged tissues by creating identical cells to replace the damaged ones.

Distinction from Meiosis

• Mitosis is not for producing sperm or egg cells; that's meiosis.
• Meiosis sounds similar to mitosis but is a different process.
• Mitosis results in identical cells.

Cell Division and Growth Control

• Cells do not divide constantly; continuous division would lead to uncontrolled growth, similar to cancer.
• Cell Cycle: Most of the cell's life is spent in interphase, where it grows, replicates DNA, and performs daily functions.
• Mitosis is a short phase in the cell cycle but crucial for cell division.

Role of DNA and Chromosomes

• Nucleus: Organelle containing DNA, crucial for storing genetic information.
• Chromosomes: Condensed DNA units; humans have 46 chromosomes in each body cell nucleus.
• Chromosomes must be duplicated before mitosis to ensure each new cell has identical genetic material.

Chromosome Duplication

• Duplicated during interphase (before mitosis).
• 46 chromosomes remain 46 even after duplication, due to counting by centromeres, but sister chromatids double to 92.

Stages of Mitosis

• PMAT Acronym: Prophase, Metaphase, Anaphase, Telophase.

Prophase

• Initial stage where the nucleus is present and chromosomes become visible (condense).

Metaphase

• Chromosomes align in the middle of the cell; nucleus disassembles.
• "M for Middle."

Anaphase

• Chromosomes move away to opposite poles of the cell.
• "A for Away."
• Movement aided by spindle fibers.

Telophase

• Chromosomes at opposite ends, new nuclei form around chromosomes.
• "T for Two" as two cells form.

Cytokinesis

• Final separation of cells by splitting the cytoplasm.
• Completes after PMAT stages.

Significance of Understanding Mitosis

• Critical for understanding growth and repair.
• Important in cancer research as cancer involves unchecked cell growth (mitosis).

Stay curious! - Amoeba Sisters