Biology (A-Level)/Meiosis

This will teach the process of meiosis to A-Level. Specifically, that of the 2008 AQA specification.

Definitions

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  • Homologous chromosomes — chromosomes that contain the same genes.
  • Maternal homologues — chromosomes from the original female parent.
  • Paternal homologues — chromosomes from the original male parent.
  • The diagram shows a chromosome.
  • Each of the strands is a chromatid.
  • Chromosomal crossover — the process by which two chromosomes pair up and exchange sections of their DNA.

Stages of meiosis

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  • Prophase I — Homologous pairs of chromosomes in a diploid cell pair up forming bivalents. Chromosomal crossover occurs.
  • Metaphase I — Bivalents line across equator of the spindle opposite homolguos pair of chromosomes.
  • Anaphase I —
  • Telophase I —
  • Interphase —
  • Prophase II —
  • Metaphase II —
  • Anaphase II —
  • Telophase II —