meosis 1

• Prophase 1


  Homologous chromosomes come together and cross over occurs. This phase is the most important as there is a crossing over involved
• Prophase 1


  • Homologous chromosomes
  • Genes aligned perfectly with other
  • Crossing over occurs
  • Synaptonemal complex - zipper like structure, holds one homolog to another
  • Synapsis - association of nonsister chromatid segments
  • Chiasmata - point of crossing over
• Tetrad


  Pairing of chromosomes
• Cohesins


  Protein that holds sister chromatids and the chromosomes together. It allows the loosening of chromatins para makapag exchange DNA ng genetic material sa chromosomes/chromatids
• Telomere


  Prevents DNA from loosening as it is very long
• Metaphase 1


  Pairs of homologous chromosomes align at the metaphase plate
• Metaphase 1


  • Both chromatids of one homolog with kinetochore microtubules
  • Chromosomes line up by homologous pair . Once tetrad is aligned to the center, it’ll be ready for the next stage
  • Chromosomes line up by homologous pair
• Anaphase 1


  Homologs separate, sister chromatids remain attached to the centromere. Each pair of homologous chromosomes separates. Each chromosome is already containing both DNA of females and males - meaning offspring is already diverse.
• Telophase 1


  Homologs separate, sister chromatids remain attached at the center, cytokinesis occur simultaneously
• No chromosomes duplication between Meiosis 1 and Meiosis 2
• Two haploid cells form; each chromosome still consists of two sister chromatids
• Two haploid cells from meiosis 1 will go 2nd round of cell division