Bio - Lecture 10

Bio - Lecture 10 - e Telophase I-The nuclear envelope...

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Sheet1 Page 1 Lecture 10 Meiosis Meiosis I Prophase I -During this phase, synapsis and crossing over occurs -> Chiasmata is where the crossing over occurs ->Synapsis is a process, the association called sister chromatid cohesion -->Synapsis is the process of the homologous chromosomes coming together -Recombination occurs between homologous chromosomes not sister chromatids Metaphase I Microtubules bind to the kinetochore (proteins that help bind the microtubule to the chromosome) at the centromeres ->In mitosis, this pulls the sister chromatids apart ->In meiosis, since homologous chromosomes are connected at the chiasmata, the microtubules pull a whole set (both sister c Anaphase I -About 90% of the time spent in meiosis I is spent in prophase I and metaphase I -In anaphase I, the chiasmata are broken -Sister chromatids are NOT separated ->Homologous chromosomes are -The separation of homologous chromosomes is random and results in independant assortment of genetic material in the gam
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Unformatted text preview: e Telophase I-The nuclear envelope beings to reform-Sister chromatids are no longer identical as in mitosis->Not identical because of recombination-Cytokinesis may or may not occur Meiosis II-After a brief interphase (without DNA replication), meiosis II occurs-Basically the same process as mitosis-THe result is four daughter cells with a haploid number of chromosomes-Each daughter is unique because of crossing over During prophase II, a new spindle apparatus forms in each cell, and the nuclear membrane breaks down In metaphase II, a completed spindle apparatus is in place in each cell. Chromosomes consisting of sister chromatids joind at In Anaphase II, when microtubules shorten, the centromeres split and sister chromatids are pulled to opposite poles of the cel l In Telophase II, nuclear envelopes reform around the sets of daughter chromosomes. After cytokineses four haploid cells resu...
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This note was uploaded on 05/06/2008 for the course BIOL 121 taught by Professor Lopez during the Fall '07 term at Lansing.

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