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Chapter 15: The Eukaryotic Cell Cycle, Mitosis, Meiosis (Michael)

Page history last edited by Michael Murphy 13 years, 4 months ago

2/13/11

 

     Chapter 15 is broken into 4 sections: Eukaryotic Cell Cycle, Mitotic Cell Division, Meiosis and Sexual Reproduction, and Variation in chromosome Structure and Number.  

     Section 15.1 covers the eukaryotic cell cycle.  The eukaryotic cell cycle is divided into four sections.  The sections are the G1 phase, S phase, G2 phase, and M phase.  The G1, S, and G2 phases are known as interphase.  During the G1 phase, the cell becomes ready to divide.  It begins to grow and reaches the G1.  the G1 checkpoint determines whether or not the cell is ready to divide.  Another checkpoint is during the G2 phase.  The G2 checkpoint looks for errors in DNA and ensures that all the DNA has been replicated.  The M checkpoint makes sure that each mitotic spindle is connected to a chromosome.

     Section 2 covers mitotic cell division.  Mitosis is cell replication and the cell gets divided into two cells.  The five processes of mitosis are prophase, prometaphase, metaphase, anaphase, and telophase. In prophase, chromosomes condense condense and the nuclear envelope starts to break apart.  During prometaphase, the nuclear completely disassociates and mitotic spindles begin to develop.  During metaphase the pairs of sister chromatids align in the middle of the cell along the metaphase plate.  Anaphase separates the sister chromatids so that each cell has a copy.  During telophase, the chromosomes reach opposite ends of the cell and nuclear envelopes begin to form.  Last cytokinesis divides the cell in half.

     Section 15.3 discusses meiosis and sexual reproduction.  Meiosis is the process by which haploid cells are produced from a cell that was originally diploid.  Gametes are the only cells that use meiosis.  Meiosis can be divided to meiosis 1 and meiosis 2.  During meiosis one, homologous father and mother chromosomes separate into two different cells.  Also during meiosis one, crossing over occurs between homologous chromosomes.  In meiosis two, the sister chromatids disperse to form two cells of their own, resulting in four cells.  

     Section four covers variation in chromosome structure and number.  This section covers deletions, duplications, inversions, and translocations.  Those are different wats in which mutations can alter chromosome structure.

 

A very cool video that discusses inversion.  The audio is very spotty though.

 

A very good video that is very descriptive about meiosis.  It has a great diagram and intense music too!

 

Meiotic behavior in nonaploid accessions of Brachiaria humidicola (Poaceae) and implications for breeding.

The article I selected talks about how irregular chromosome segregation leads to unbalanced gamete formation

 

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