Phases of Meiosis and Chromosome Structure

Magnification Levels in Meiosis

• Various magnification levels are used to observe the different stages of meiosis:
  • Magnification: 49x
  • Magnification: 41x (Prophase I)
  • Magnification: 360x (Meiosis II)
  • Magnification: 800x (Anaphase II)
  • Magnification: 400x (Telophase I)
  • Magnification: 51x, 6x, 74x (various stages)

Overview of Meiosis

• Meiosis consists of two main stages: Meiosis I and Meiosis II, each further divided into subphases.
• Key phases are:
  • Prophase I: Homologous chromosomes align and undergo synapsis.
  • Metaphase I
  • Anaphase I
  • Telophase I
  • Prophase II
  • Metaphase II
  • Anaphase II
  • Telophase II

Prophase I

• Chromosomes and Synapsis:

  • During prophase I, each pair of homologous chromosomes aligns side by side in a process known as synapsis.
  • Homologous chromosomes are not identical; they contain the same genes but can carry different alleles (variations of a gene).

• Tetrads:

  • At synapsis, homologous chromosomes come together, and because each consists of two chromatids, a pair of homologous chromosomes comprises four chromatids, termed a tetrad.
  • Each tetrad consists of a pair of sister chromatids synapsing with another pair of sister chromatids.

• Chromatid Structure:

  • In a tetrad, there are two homologous chromatids that are identical.

Key Comparisons with Mitosis

• Important question to explore: Which phases of meiosis are most similar to the phases of mitosis?
• Understanding the differences and similarities between meiosis and mitosis is crucial for grasping concepts of genetic variation and cellular reproduction.