BIOM 180Bang, Michel (Christofer)2013 FallWeek 3Lecture 6January 25Steps of MeiosisDivided into 2 major phases:- Meiosis I- Meiosis IIEach meiotic division is divided into 4 (5) stages:- Prophase/Prometaphase- Metaphase- Anaphase- TelophaseProphase/Prometaphase I- Homologous pairs line up with each other-synapsis- Spindles attach to each chromosome- 4 chromatids of each homologous for a tetrad, or bivalentMetaphase I- Chromosomes are at the equatorial plate- Homologous pairs are held together at the chiasmataAnaphase I- Homologous chromosomes separate-disjunction- Each chromosome consists of two chromatidsTelophase I- Nuclear envelope divides, followed by an interphase-interkinesis- Occurs in some organismsMeisosis IIEvery stage is repeated except the DNA does not replicate AND the stages deal with ChromatidsMitosis vs. Meiosis II DifferencesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- DNA does not replicate prior to meiosis II- Meiosis II the sister chromatids may not be identical b/c of crossing over- Number of chromosomes at the equatorial plate in meiosis II is HALF the number of the in
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