Genetics CH12

  1. Homologus Chromosomes
    the members of a chromosome pair that conatin the same genes and that pair during meiosis.
  2. Nonhomologus Chromosomes
    Chromosomes that contain diferent genes and that do not pair during meiosis.
  3. Sex Chromosomes
    The chromosomes that are represented differently in the two sexes in many eukaryotic organisims.
  4. Autosomes
    Chromosomes other than sex chromosomes
  5. Centromere
    Is the constriction along the lengenth of the chromosome.
  6. Metacentric Chromosome
    Has the centromere about the center so the chromosome appears to have two approximately equal arms.
  7. Submetacentric Chromosomes
    Have one arm longer than the other
  8. Acrocentric Chromosomes
    Have one arm with a stalk and often with a bulb on it.
  9. Telocentric Chromosomes
    have only one arm, because the centromere is at it end.
  10. Karyotype
    A complete set of all metaphase chromosomes in a cell is called the cell's karyotype.
  11. Q Vs. P arm of the Chromosome
    • Q is the larger arm separated by the Centromere
    • P is the smaller arm separated by the Centromere.
  12. Mitosis
    The cycle of growth AKA nuclear division of Karyokinesis
  13. Cell Cycle
    • The cycle of growth, Mitosis, and cell division.
    • INterphase and Mitotic phase
  14. Interphase
    Consists of 3 Stages

    • G1- Gap Phase-Presynthesis phase- the cell prepares for DNA and Chromosome Replication in S phase
    • S-Synthesis Phase- DNA is synthesized
    • G2- Gap2- Post synthesis Stage - The cell prepares for cell division or the M stage.
  15. Sister Chromatids
    Replicated DNA from the S phase which are 2 exact copies.
  16. Chromatids
    One of the two distinct longitudinal subunits of all replicated chromosomes that become visible between early prophase and metaphase of mitosis.
  17. Daughter Chromatids
    When the centromeres separate the sister chromatids alternative names.
  18. Five Stages of Mitosis
    • Prophase
    • Prometaphase
    • metaphase
    • anaphase
    • telophase
  19. Meiosis
    The successive division of a diploid nucleus after only one DNA replication cycle.
  20. gameteogenesis
    THe formation of male(sperm) and female(eggs) gametes (haploid) during meiosis.
  21. Meiosis
    • The chromosome number is reduced from diploid to haploid.
    • Occurs during gameteogenesis in animal (production of gametes)
    • Meiosis I results in the separation into sister Chromatids
    • Meiosis II results in the separation of the sister chromatids.
    • The Meiosis of a single diploid cell produces 4 haploid cells.
  22. Meiosis I
    • Consists of 5 stages
    • Prophase I
    • Pro Metaphase I
    • Metaphase I
    • Anaphase I
    • Telophase I
  23. Prophase I
    The important difference between Mitosis and Meiosis I is that homologus chromosomes pair with each other in Meiosis and Crossing over occurs.

    Early Prophase I- Leptonema- Extended Chromosomes condense and become visible as long thin threads. once here a cell is comitted to meiosis.

    Middle Prophase I - Zygonema- Chromosomes align and form a synapsis and synaptomeal complex.

    Middle Prophase I- Pachynema- Crossing over occurs if the chromosomes are different they produce a recombinant chromosome. (most important step in genetics)

    Late Prophase I- Diplonema- the synaptonemal Complex disassembles and the results of crossing over form a x called a chiasma and they move apart.

    Later Prophase I- Diakinesis- The chromosomes condense even more, and the 4 members of the tetrads become visible.
  24. Prometaphase I
    • Results of crossing over become visible
    • Nuclear Envelope breaks down.
    • Meiotic Spindle enters the former nuclear area.
    • Kinetochore microtubules attach to chromosomes
Card Set
Genetics CH12