Lecture Notes: Side-by-Side Comparison of Mitosis and Meiosis

Introduction

• Key Vocabulary: Chromosome, Chromatid, Chromatin, Transcription, Translation, Mitosis, Meiosis.
• The video is a split screen comparison of mitosis and meiosis.
• Objective: Understand similarities and differences between mitosis and meiosis.

Overview of Mitosis and Meiosis

• Mitosis results in body cells.
• Meiosis results in sperm and egg cells (gametes).
• Both processes start with a diploid cell (2n = 46 chromosomes in humans).
• During interphase, chromosomes duplicate (46 chromosomes become 92 chromatids).

Stages of Mitosis and Meiosis (PMAT)

• Prophase: Chromosomes condense and become visible.
  • Mitosis: Chromosomes condense.
  • Meiosis Prophase I: Homologous chromosomes pair up and crossing over occurs.
• Metaphase: Chromosomes align in the middle of the cell.
  • Mitosis: Chromosomes line up in a single file.
  • Meiosis Metaphase I: Chromosomes align in pairs.
• Anaphase: Chromatids or chromosomes move to opposite ends of the cell.
  • Mitosis: Chromatids are pulled away.
  • Meiosis Anaphase I: Chromosomes are pulled away.
• Telophase: New nuclei form around separated chromosomes.
  • Mitosis and Meiosis Telophase I: Chromosomes reach cell poles, and cytokinesis follows.

Outcome of Mitosis and Meiosis

• Mitosis: Results in two identical, diploid cells (46 chromosomes each in humans).
• Meiosis II:
  • Prophase II: No crossing over.
  • Metaphase II: Chromosomes align in single file.
  • Anaphase II: Chromatids are pulled away.
  • Telophase II: Ends in four non-identical, haploid gametes (23 chromosomes each in humans).

Additional Notes

• Gametes: Haploid cells (23 chromosomes in humans).
• Zygote Formation: Sperm and egg combine to form a diploid cell (zygote), initiating mitosis for organism growth.

Conclusion

• Mitosis and meiosis are crucial for growth, repair, and reproduction.
• End note from the Amoeba Sisters: Stay curious!