Summary OCR A/AS-Level Biology 2.6.3 Stages of Meiosis

Stages Of Meiosis
Prophase I Prophase II
 Chromosomes supercoil and condense  Chromosomes supercoil and condense
into chromatids into chromatids
 Chromatids take up stain mor easily and  Chromatids take up stain mor easily and
become more distinct become more distinct
 Nuclear envelope breaks down  Nuclear envelope breaks down
 Centrioles divide and migrate to the  Centrioles divide and migrate to the
poles poles
 Chromosomes form homologous pairs  Non-identical
and crossing over occurs
Metaphase II
Metaphase I  Spindle fibres attach to centrioles and
 Spindle fibres attach to centrioles and centromeres of chromatids
centromeres of homologous pairs  Each centromere attaches to both poles
 Each centromere attaches to both poles by spindle fibres
by spindle fibres  Chromatids line up at the equator
 Homologous pairs line up at the equator
Anaphase II
 Independent assortment occurs
 Centromeres divide
Anaphase I  Chromatids are pulled apart towards the
 Centromeres divide poles
 Homologous pairs are pulled apart
Telophase II
towards the poles
 Chromatids reach the poles and start to
Telophase I uncoil into chromosomes
 Nuclear envelope starts to reform  Chromosomes become less distinct
around each set of chromosomes  Nuclear envelope starts to reform
 Cell divides by cytokinesis resulting in around each set of chromosomes
haploid cells