Mitosis and Meiosis (Science Week 2)

• Mitosis- produces the two identical cells with the same number of chromosomes.
• 4 stages of Mitosis (PMAT)

  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
• Prophase

  • The chromatin in the nucleus begins to shorten and thicken which is called chromatid and finally forming rod-like structures known as chromosomes.
• Metaphase

  • The spindle is fully developed and the chromosomes begin to attach themselves to it.
• Anaphase

  • The sister chromatid begins to separate and moves towards the poles.
• Telophase

  • Start to uncoil and become indistinct under the light microscope.
• Cytokinesis

  • The division of the cytoplasm to form two separate daughter cells immediately after mitosis
• Meiosis

  • Cell undergoes two rounds of cell division to produce four daughter cells.
• Leptotene

  • Each chromosome is made up of two long threads of sister chromatids as a result of replication during the S phase of the cell cycle.
• 8 stages of Meiosis

  • Prophase I
  • Metaphase I
  • Anaphase I
  • Telophase I
  • Prophase II
  • Metaphase II
  • Anaphase II
  • Telophase II
• Zygotene

  • The chromosomes begin to pair off. Pairs of chromosomes are called homologues chromosomes and this pairing process is exact.
• Pachytene

  • Chromosomes contact due to repeated coiling
• Chiasma

  • Crossing over takes place during this stage where a segment of a sister chromatid of one chromosomes is exchanged with the same segment of the sister chromatid of the homologues chromosome through the formation of a cross-linkage of the segments.
• Diplotene

  • Chromosomes begin to uncoil
• Diakinesis

  • Paired chromosomes disperse in the nucleus.
• Metaphase I

  • Paired chromosomes arrange themselves along with the equatorial plate.
• Anaphase I

  • The spindle fibers form and attach to the centromeres of the chromosomes.
• Telophase I

  • Cytokinesis follows and two daughter cells are formed
• Mitosis

  • Body cells/Diploid

  Meiosis

  • Sex cells/Haploid