Meiosis I
- Created by: heatherbaker
- Created on: 07-03-16 19:15
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- Meiosis
- Meiosis II
- Anaphase II
- Centromeres divide chromatids pulled to opposite poles by spindle fibres
- Chromatids randomly segregate.
- Metaphase II
- Chromosomes arrange selves in on equator at spindle at centromeres.
- Chromatids of each chromosome are randomly assorted.
- Telophase II
- Nuclear envelopes reform around haploid daughter nuclei.
- In animals: two cells divide to form haploid cells.
- In plants: tetrad of four haploid cells form.
- Cells divide by cytokinesis
- Prophase II
- Nuclear envelope formed, breaks down again.
- Nucleolus disappears, chromosomes condense, spindles form
- Anaphase II
- Meiosis I
- Metaphase I
- Bivalents line up along equator of spindle attached at centromeres. Chiasmata still present.
- Bivalents arranged randomly with each member of homologous pair facing opposite poles.
- Allows chromosomes to segregate independently in next stage.
- Telophase I
- Cell divides by cytokinesis brief interphase, chromosomes uncoil.
- Two new nuclear envelopes form around each set of chromosomes at each pole.
- Prophase I
- Chromatin condenses, supercoils. Chromosomes shorten and thicken.
- Chromosomes come together in homologous pairs- form bivalents.
- Non-sister chromatids wrap around each other and attach at chiasmata.
- They may swap chromatid sections in crossing over.
- Nucleolus disappears nuclear envelope disintegrates,spindle forms.
- Anaphase I
- Homologous chromosomes in each bivalent pulled to opposite poles by spindle microtubules.
- Centromeres don't divide.
- Chiasmata separate and lengths of chromatid crossed over remain with new chromatid.
- Metaphase I
- Meiosis II
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