Lecture Notes: Mitosis and Cell Division

Introduction

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• Common occurrences indicating cell division:
  • Healing of cuts on skin.
  • Growth of nails.
  • Human growth over time.

Mitosis

• Definition: A type of cell division performed by most body cells.
• Importance:
  • Essential for growth (e.g., becoming larger than a child).
  • Critical for repairing damaged tissues, like cuts.

Key Characteristics of Mitosis

• Produces identical cells; crucial for replacing lost or damaged cells with the same type (e.g., skin cells).
• Not involved in making sperm or egg cells (that’s meiosis).

Cell Cycle and Mitosis

• Cells are not constantly dividing; they spend most of their time in interphase:
  • In interphase, cells grow, replicate DNA, and carry out daily functions.
  • Mitosis is a short part of the cell cycle.

DNA and Chromosomes

• DNA: Genetic information must be replicated identically in new cells.
• Chromosomes: Condensed units of DNA, making it easier to distribute during cell division.
  • Humans have 46 chromosomes (in most body cells).
  • Chromosomes are duplicated in interphase before mitosis.

Mitosis Stages (PMAT)

1. Prophase
   • Nucleus is present, chromosomes condense.
2. Metaphase
   • Chromosomes line up in the middle of the cell.
   • Nucleus disassembled.
3. Anaphase
   • Chromosomes move away to opposite poles of the cell.
   • Spindle fibers assist in movement.
4. Telophase
   • Chromosomes at opposite ends, new nuclei form.
   • Two identical cells are forming.

Cytokinesis

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

Importance of Mitosis

• Essential for understanding growth, repair, and cancer research.
• Cancer is characterized by uncontrolled mitosis, leading to uncontrolled cell growth.

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• Stay curious and continue exploring cell division!