Meiosis

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  • Created by: Joko
  • Created on: 05-05-12 14:52

= reduction division which makes the resulting daughter cells haploid. It can be used for sexual reproduction.

  • In sexual reproduction, the offspring are genetically different from each other and from the parents.
  • Each parent produces special reproductive cells called gametes. One of these from each parent fuse together at fertilisation to form a zygote.
  • In order for the zygote to be a diploid cell with two sets of chromosomes in the nucleus, the number of chromosomes in each gamete needs to be haploid.
  • Meiosis involves two separate divisions: Meiosis I and Meiosis II. Each division has four stages: Prophase, Metaphase, Anaphase and Telophase.

Note: Can be remembered by PMAT.

  • In Interphase, before Meiosis I, the DNA replicates. Each chromosome then consists of two identical sister chromatids, joined at the centromere.

Meiosis I

Prophase I

1. The chromatin condenses and supercoils so the chromosomes shorten and thicken. They can then be seen with a light microscope.

2. The chromosomes come together in their homologous pairs (matching pairs) to form a bivalent. Each member of the pair has the same gene at

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