test 2 outline

test 2 outline - SLIDE SET V OUTLINE Somatic cells...

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SLIDE SET V OUTLINE Somatic cells: diploid (body) o Contain 2 sets of chromosomes o Human skin, muscle, liver cell (46 chromosomes) Germ cells: gametes o Haploid o Oocytes, egg cells, sperm cells o 23 chromosomes=1 set o They are haploid because half of each set comes from each parent and fuse together to make a diploid. # Chromosomes in a set = n o n=23 = haploid sex cells o 2n=46 = diploid body cells A karyotype (a chart of stained chromosomes) is a standard way of displaying the number of chromosomes in a call o Chromosomes exist in pairs o Homologous: homologues: chromosome pair (code for same gene) o Non-homologous: differ in number and kind of genes o In a karyotype (23 sets): #1-22= autosomes (appear in both sexes), and #23= sex chromosomes (1 pair of sex determining XX or XY) An allele is a different version of the same gene. Somatic cell division must preserve the chromosome number- which is species specific. Cell Cycle Cell growth and mitotic division of the nucleus that preserves chromosome number in daughter cells and are the two components of the cell cycle. Unicellular (asexual) reproduction o Binary fission (getting 2 identical daughter cells) Ex. Prokaryotes (bacteria) Development: fertilized egg cell (zygote) Cell division functions in cell renewal (tissue repair) Eykaryotic cell cycle: a continuous process New “daughter” cells New cell grows (its job) Decision made to divide or die Chromosomes replicate Cell prepare to divide Cell cycle Interphase:
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o G1: cell birth initiation of DNA synthesis (S phase) Cell grows and metabolizes Genes are regulated o S phase: chromosomes replicate o G2 phase: After the DNA replicates, cells must synthesize proteins and structures to prepare for division. Centromere replicates Prophase: M phase begins: centromeres move to opposite poles o Spindle forms o Nuclear envelope disintegrates o Replicated chromatin begins to condense o Replicated chromosome=2 sister chromatids joined at centromere Pro-metaphase: nuclear membrane is dissembled o Chromosomes clearly distinct o Kinetochores appear at centromeres A protein-DNA complex in the centromeric region that attaches sister chromatids to the spindle o Spindle apparatus form Metaphase: spindle microtubules move chromosomes o Chromosomes align single file at the midline o Sister chromatids face opposite poles Anaphase: centromeres split o Spindle microtubules pull apart sister chromatids toward opposite poles Telophase: spindle disassembles o Nuclear membrane reappears o Mitosis/nuclear division now complete Cytokineses: cell membrane pinches at cleavage furor o Cytoplasmic division now complete o 2 daughter cells result with same chromosome # as parental cell with identical DNA Controls of cell cycle Cyclins: proteins that fluctuate in concentration throughout the cell cycle Cdks: cyclin dependent kinases: active when complexed with cyclin
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This note was uploaded on 04/08/2008 for the course BIO bsc2011L taught by Professor Spears during the Spring '08 term at FSU.

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test 2 outline - SLIDE SET V OUTLINE Somatic cells...

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