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Unit 8 (Meiosis (parts(meiosis I) (early prophase I: (The chromosomes have…

- - - - The chromosomes have already been duplicated at this phase
        Spindles have formed and are connected to the nucleus
        Nucleus is still present in early prophase I
        The chromosomes also ‘crossover’ at a chiasma and perform genetic recombination
        diploid
        telomere attaches to each other
    - - Homologous chromosomes are paired together to form a tetrad
        Nucleus disappears
        Spindles have attached to the chromosomes
        diploid
    - - Spindles are attached to the chromosomes, and are located at each end of the cell
        The chromosomes are still coiled in this phase
        diploid
        telomeres exchange
    - - Dragged by the spindles, the homologous chromosomes are separated
        The genetic recombination that was performed in both metaphase I and prophase I is shown as the chromosomes that share genetic info with the other parent chromosome
        Sister chromatids remain joined
        diploid
    - - Spindles disappear after the chromosome are pulled to the opposite sides of the cell
        Nucleus reforms
        The cell begins to split
        Haploid
  - - - This is the beginning of meiosis II
        No new chromosome replication takes place prior to this step
        Like in prophase I, centrioles duplicate by the separation of two pairing centrioles, then the creation of a daughter centriole next to each original centriole
        The two pairs part into two centrosomes
        Spindle apparatus forms and the nuclear envelope disintegrates
    - - Daughter cells complete form of spindle apparatus
        Single chromosome align on metaphase plate
        For each one, each of the sister chromatids face opposite poles
    - - The centromeres separate
        two chromatids of each chromosome move to opposite poles on the spindle.
        The separated chromatids are chromosomes now
    - - Chromosomes have reached the opposite ends of the cell
        The new nuclear membrane forms around the now separated chromosomes
    - - Cell division occurs
        The two cells separate
        A male cell will have a sperm cell while the female gets an egg cell
- - - - -chromosomes duplicate
      - nuclear membrane is still present
    - - nuclear membranes disappear
      - spindles are formed and attached
      - chromosomes are lined up in center of cell
      - centriole forms
    - - chromosomes are split
      - chromosome legs are pulled towards edge of cell
    - - nuclear division
      - nucleus begins to come to center
    - - cytoplasic division
      - 2 cells
- - - - adult stem cells
      - stem cells from blood and bone marrow can be used to treat diseases
      - cells may be recognized as foreign
    - - embryos that are isolated and used as stem cells
      - cells may be attacked
      - ethics
    - - artifically modified stem cells
      - safety isn't guanteed
- - - - cells grow and produce more proteins + organelles
      - longest part of process (11 hours)
      - 1 set of DNA present
      - P53 checks DNA during check point
    - - further prepares for mitosis by making proteins
      - 2 sets of DNA present
      - has most organelles
      - cells are checked for 2 sets of chromosomes
    - - dna replication occurs
      - 2 sets of DNA present
    - - after G1
      - resting process (doesn't continue cycle)
  - - - sped up mitosis
      - named oncogenes
      - cells can form tumors by lack of receptors and a giant compiling of cells through differation
      - require 1 allele
      - stimulates protein
      - gain of function
    - - decreased mitosis
      - requires 2/both alleles
      - loss of function
      - inhibits proteins
      - mutation is like taking foot off brake, which leads to uncontrolled mitosis