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  • Created by: christaj
  • Created on: 09-12-15 08:12
  • Meiosis- It is a reduction division. This means that the daughter cells have half of the original number of chromosomes. They are haploid.
  • Each division has four stages:
    • Prophase
    • Metaphase
    • Anaphase
    • Telephase
  • Before meiois 1, interphase takes place. This is when the DNA replicates. Each chromosome consists of two identical chromatids, joined at the centromere.
  • The cell will have four instead of two original copies of each chromosme.
  • Each chromosome is a chromatid.
  • A pair is called a sister chromatid.
  • Sister chromatids are joined together in the middle by a centromere.

Meiosis 1


  • The chromatins condenses and supercoils.
  • Supercoiling makes the chromosomes shorter and thicker.
  • The chromosomes come together as homologous pairs to form a bivalent.
  • A bivalent is a pair of homologous chromosomes.
  • Each member of the pair have the same gene at the same loci. They each have the one maternal and one paternal chromosome.
  • Non sister chromatids wrap around each other and form chiasmata.
  • The undergo a process called crossing over. This is when the chiasmata may swap section s of chromatid with one another.
  • The nucleolous disappears and the nuclear envelope breaks down.
  • A spindle is formed.  It is made of protein microtubles.


  • The bivalent line across the equator of the cell and they attach to spindle fibres at the centromere.
  • Each member of the homologous pairing face opposite poles.


  • The homologous chromosome pair are pulled to opposite end of the poles.
  • This is because the spindles contract pulling them apart.


  • There is two nuclear envelope that forms around the chromosomes at each end of the poles.
  • In animals, the cytoplasm divides by cytokenesis and two haploid daughter cells are formed.
  • In plants, the cell goes straight from anaphase 1 to meiosis 2.

Meiosis 2

  • This is the same as meiosis one, however, it occurs with half the number of chromosomes.
  • In anaphase 2, the sister chromatids are seperated. Each new daughter cell…


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