AQA A Level Biology

Revision Notes

4.3.3 Meiosis


  • Meiosis produces daughter cells that are genetically different from each other and to the parent cell
  • This is due to the processes of independent assortment and crossing over
  • Independent assortment
    • The alleles of two (or more) different genes get sorted into gametes independently of one another
    • The allele a gamete received for one gene does not influence the allele received for another gene
    • This is because homologous chromosomes line up in random orientations at the middle of the cell at metaphase as they prepare to separate, meaning that the same parent cell can produce different combinations of chromosomes in the daughter cells
  • Crossing over
    • The process whereby a chromatid breaks during meiosis and rejoins to the chromatid of its homologous chromosome so that its alleles are exchanged

Meiosis, IGCSE & GCSE Biology revision notes

The daughter cells have unique allele combinations – they are genetically different.

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Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.

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