Biology Chapter 9 terms pt2

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Biology Chapter 9 terms pt2
2012-04-14 00:41:57
Biology Chapter

Biology Chapter 9 terms pt2
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  1. the physical location of a gene on a chromosome.
    locus (plural, loci)
  2. in eukaryotic organisms, a type of nuclear division in which a diploid nucleus divides twice to form four haploid nuclei.
  3. meiosis followed by cytokinesis.
    meiotic cell division
  4. in mitosis, the stage in which the chromosomes, attached to spindle fibers at kinetochores, are lined up along the equator of the cell; also the approximately comparable stages in meiosis I and meiosis II.
  5. a type of nuclear division, used by eukaryotic cells, in which one copy of each chromosome (already duplicated during interphase before mitosis) moves into each of two daughter nuclei; the daughter nuclei are therefore. genetically identical to each other.
  6. mitosis followed by cytokinesis.
    mitotic cell division
  7. a change in the base sequence of DNA in a gene; normally refers to a genetic change significant enough to alter the appearance or function of the organism.
  8. a subunit of which nucleic acids are composed; a phosphate group bonded to a sugar (deoxyribose in DNA), which is in turn bonded to a nitrogen-containing base (adenine, guanine, cytosine, or thymine in DNA).
  9. the first stage of mitosis, in which the chromosomes first become invisible in the light microscope as thickened, condensed threads and the spindle begins to form; as the spindle is completed, the nuclear envelope breaks apart, and the spindle microtubules invade the nuclear region and attach to the kinetochores of the chromosomes. Also, the first stage of meiosis In meiosis I, the homologous chromosomes pair up, exchange parts at chiasmata, and attach to spindle microtubules; in meiosis II, the spindle re-forms and chromosomes attach to the microtubules.
  10. the formation of new combinations of the different alleles of each gene on a chromosome; the result of crossing over.
  11. one of the pair of chromosomes that usually determines the sex of an organism; for example, the X and Y chromosomes of mammals.
    sex chromosome
  12. a form of reproduction in which genetic material from two parent organisms is combined in the offspring; normally, two haploid gametes fuse to form a diploid zygote.
    sexual reproduction
  13. microtubules organized in a spindle shape that separate chromosomes during mitosis or meiosis.
    spindle microtubule
  14. an undifferentiated cell that is capable of dividing and giving rise to one or more distinct types of differentiated cell(s).
    stem cell
  15. the nucleotides at the end of a chromosome that protect the chromosome from damage during condensation, and prevent the end of one chromosome from attaching to the end of another chromosome.
  16. in mitosis and both divisions of meiosis, the final stage, in which the spindle fibers usually disappear, nuclear envelopes re-form, and cytokinesis generally occurs. In mitosis and meiosis II, the chromosomes also relax from their condensed form.