Notes - SI Notes Chapter 12 10/01/2010 (Leslie) Binary...

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SI Notes Chapter 12 – 10/01/2010 (Leslie) Binary fission – bacteria divide Somatic cells – body cells o Diploid 2n=46 chromosomes o Mitosis Gametes – sex cells o Haploid n=23 chromosomes o Miosis Cell cycle – prepares cell for division o Interphase - Cell grows Restriction points – decide where to continue cell cycle o Cell cycle S – DNA replication - check for damage M phase – mitosis/meiosis - cell will enter if damaged Cells may be destroyed or fixed MAD genes – signal that the spindle is attached to centromere Kinetochore – special region of centromere that the spindle will attach to Cell chemicals – power cell cycle o Kinase – enzymes are phosphorilated from ATP
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o Cyclin Normal cells – divide 20-50 times o Have telomeres – located on the end of chromosomes Non coded regions of chromosome Get shorter as you age Cell dies when it gets to the end o Telomerase Only enzyme that can replace it o Cancer cells don’t obey Density dependant inhibition o When cells next to each other won’t divide Ex. Maximum number of people in the room Anchorage dependency o Cell won’t divide if not attached to where it’s supposed to be Chapter 12 – 10/04/2010 (Shane) Mitosis o Somatic cells Ex. Hair cell o Diploid 46 chromosomes in human cells o The new cell and the old cell are identical
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o Prophase Break down nuclear membrane Chromosomes coil and condense so they’re easier to move First time chromosomes are visible o Metaphase Chromosomes line up on metaphase plate In the middle of the cell Spindle fibers attach o Anaphase Chromosomes pulled apart o Telophase Reverse of prophase Cytokinesis When the cell actually separates Plant cells divide from the inside out and animal cells divide from the outside in Normal cells o Go through mitosis 20-50 times Because telomere, which controls cellular suicide, gets shorter with each division; When telomere reaches the bottom the cells dies o Density dependent inhibition When two cells meet they stop dividing o Anchorage dependency Cells have to be attached to something to divide
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o P53 – Master Tumor Suppressor Cancer cells o Divide forever because they have telomerase, which keeps telomeres lengthened so they never reach the bottom o P53 If it’s turned on, the tumor is benign If it’s turned off, the tumor is malignant Chapter 13 10/11/2010 (Shane) n = number of homologues 2n = haploid; n = diploid For each chromosome, they’re two sister chromatids Centromere – what holds the sister chromatids together 2n=72 o Number of chromosomes - 72 o Number of homologues - 36 o Number of sister chromatids - 144 o Number of centromeres – 72 Meiosis o Prophase I Synapsis Chiasmata
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o Metaphase I Chromosomes line up two by two o Anaphase I Homologous chromosomes separate o
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This note was uploaded on 08/19/2011 for the course BSC 2010c taught by Professor Janewaterman,pamelathomas during the Spring '07 term at University of Central Florida.

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Notes - SI Notes Chapter 12 10/01/2010 (Leslie) Binary...

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