🧬

Mitosis vs. Meiosis Explained

Oct 16, 2024

Comparison of Mitosis and Meiosis

Overview

  • Purpose of the Lecture: Provide a side-by-side comparison of mitosis and meiosis.
  • Processes Overview:
    • Mitosis results in body cells.
    • Meiosis results in gametes (sperm and egg cells).
    • Both processes start with diploid cells (2N), meaning two sets of chromosomes (46 in humans).
    • Interphase precedes both, involving chromosome duplication.

Interphase

  • Chromosomes duplicate during interphase, though it's not part of mitosis or meiosis.

Mitosis vs. Meiosis Stages

Acronym: PMAT (Prophase, Metaphase, Anaphase, Telophase)

  • Mitosis:
    • One cycle of PMAT.
    • Results in two identical diploid cells.
  • Meiosis:
    • Two cycles of PMAT (Meiosis I and Meiosis II).
    • Results in four non-identical haploid cells (23 chromosomes each in humans).

Detailed Stages

Prophase

  • Mitosis: Chromosomes condense and become visible.
  • Meiosis I: Chromosomes pair with homologous chromosomes and may exchange genetic material (crossing over).

Metaphase

  • Mitosis: Chromosomes line up single file in the middle of the cell.
  • Meiosis I: Homologous chromosome pairs align in the middle.

Anaphase

  • Mitosis: Chromatids are pulled apart to opposite sides.
  • Meiosis I: Whole chromosomes are pulled apart.

Telophase

  • Mitosis: Chromosomes reach opposite ends; nuclei form.
  • Meiosis I: Chromosomes reach opposite ends; nuclei form.

Cytokinesis

  • Follows telophase, dividing the cytoplasm completely.
  • Mitosis: Results in two identical diploid cells.
  • Meiosis:
    • Meiosis II begins:
      • Prophase II: Chromosomes condense.
      • Metaphase II: Chromosomes align single file.
      • Anaphase II: Chromatids are pulled apart.
      • Telophase II: Chromosomes at opposite ends; nuclei form.
    • Results in four non-identical haploid gametes.

Importance

  • Mitosis: Essential for organism growth and cell replacement.
  • Meiosis: Produces gametes for sexual reproduction.
  • Gametes: Haploid cells that combine to form diploid zygote.

Fun Fact

  • Some insects like mosquitoes have 6 chromosomes, making it easier to visualize in diagrams.

End Note: The summary encourages further exploration of the details for each stage and the processes involved. Stay curious!

Full transcript