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Understanding Mitosis and Cell Division

Oct 16, 2024

Lecture Notes on Mitosis

Introduction

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  • Everyday examples of growth and healing (cuts, nail growth, etc.).

What is Mitosis?

  • Definition: Mitosis is a type of cell division performed by most body cells.
  • Importance:
    • Enables growth by creating new cells.
    • Repairs damaged tissues (e.g., cuts).

Mitosis vs. Meiosis

  • Mitosis:
    • Produces body cells.
    • Creates identical cells (e.g., skin cells).
  • Meiosis:
    • Produces sperm and egg cells.
    • Different process, not discussed in detail here.

Cell Division and Cancer

  • Cells do not divide continuously; regulated process is crucial.
  • Cancer: Uncontrolled cell growth results from faulty regulation of mitosis.

The Cell Cycle

  • Interphase:
    • Majority of cell life spent in interphase.
    • Cells grow, replicate DNA, and perform daily functions.
    • Important for preparing DNA for mitosis.

DNA and Chromosomes

  • Nucleus: Contains DNA, vital for genetic information.
  • Chromosomes:
    • DNA condensed into structures for easier movement during cell division.
    • Humans have 46 chromosomes in body cells.
    • Chromosomes duplicate in interphase, resulting in 92 chromatids (still counted as 46 chromosomes due to centromeres).

Steps of Mitosis (PMAT)

  1. Prophase:
    • Chromosomes become visible and condense.
    • Nucleus is still present at the start.
  2. Metaphase:
    • Chromosomes align in the middle of the cell.
    • Nucleus has disassembled.
  3. Anaphase:
    • Chromosomes are pulled apart to opposite ends of the cell.
    • Movement aided by spindle fibers.
  4. Telophase:
    • Chromosomes reach opposite poles and new nuclei form around them.
    • Two nuclei, each with 46 chromosomes, are visible.

Cytokinesis

  • Final separation of the cell into two daughter cells by splitting the cytoplasm.
  • Occurs after PMAT stages of mitosis.

Conclusion

  • Understanding mitosis is crucial for comprehending growth, repair, and cancer research.
  • Controlled cell division is vital for healthy organism function.

Full transcript