BRAINCAKEMetaphase 1
In metaphase I the bivalents (pairs of homologous chromosomes) line up across the equator of the spindle. Spindle fibres from opposite poles attach to the centromeres: the centromere of one homologous chromosome is attached to fibres from one pole, and the centromere of its partner to fibres from the other pole.
This is the key difference from metaphase of mitosis, in which individual chromosomes line up singly on the equator. In metaphase I the chromosomes are arranged in pairs.
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Key terms in this lesson
- bivalent
- A pair of homologous chromosomes joined together during prophase I of meiosis, containing four chromatids.
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