bio ch 18

  1. anaphase
    mitotic phase during which daughter chromosomes move toward the poles of the spindle
  2. apoptosis
    programmed cell death involving a cascade of specific cellular events leading to death and destruction of the cell
  3. aster
    short, radiating fibers about the centrioles at the poles of a spindle
  4. barr body
    dark-staining body in the nuclei of female mammals that contains a condensed, inactive X chromosome.
  5. cell cycle
    repeating sequence of cellular events that consists of interphase, mitosis, and cytokinesis
  6. centriole
    cellular structure, existing in pairs, that possibly organizes the mitotic spindle for chromosomal movement during mitosis and meiosis
  7. centromere
    constriction where sister chromatids of a chromosome are held together
  8. centrosome
    central microtubule organizing center of cells. in animal cells, it contains two centrioles
  9. cleavage furrow
    indentation that begins the process of cleavage, by which human cells undergo cytokinesis
  10. crossing over
    exchange of segments between non sister chromatids of a tetrad during meiosis
  11. cytokinesis
    division of the cytoplasm following mitosis and meiosis
  12. daughter cell
    cell that arises from a parent cell by mitosis or meiosis
  13. deletion
    change in chromosome structure in which the end of a chromosome breaks off or two simultaneous breaks lead to the loss of an internal segment; often causes abnormalities
  14. diploid (2n)
    cell condition in which two of each type of chromosome are present in the nucleus
  15. duplication
    change in chromosome structure in which a particular segment is present more than once in the same chromosome
  16. fertilization
    union of a sperm nucleus and an egg nucleus, which creates a zygote
  17. gamete
    haploid sex cell; the egg or a sperm, which join in fertilization to form a zygote
  18. halpoid (n)
    the n number of chromosomes - half the diploid number; the number characteristic of gametes, which contain only one set of chromosomes
  19. homologous chromosome
    member of a pair of chromosomes that are alike and come together in synapsis during prophase of the first meiotic division
  20. homologue
    member of a homologous pair of chromosomes
  21. interkinesis
    period between meiosis I and meiosis II, during which no DNA replication takes place.
  22. interphase
    cell cycle stage during which growth and DNA synthesis occur when the nucleus is not actively dividing
  23. inversion
    change in chromosome structure in which a segment of a chromosome is turned around 180 degrees; this reversed sequence of genes can lead to altered gene activity and abnormalties
  24. meiosis
    type of a nuclear division that occurs as part of sexual reproduction in which the daughter cells receive the haploid number of chromosomes in varied combinations
  25. metaphase
    mitotic phase during which chromosomes are aligned at the equator of the mitotic spindle
  26. mitosis
    type of cell division in which daughter cells receive the exact chromosomal and genetic makeup of the parent cell; occurs during growth and repair
  27. mitotic spindle
    microtubule structure that brings about chromosomal movement during nuclear division
  28. monosomy
    one less chromosome than usual
  29. nondisjunction
    failure of homologous chromosomes or daughter chromosomes to separate during meiosis I and meiosis II, respectively
  30. oogenesis
    production of an egg in females by the process of meiosis and maturation
  31. parent cell
    cell that divides so as to form daughter cells
  32. polar body
    in oogenesis, a nonfunctional product; two to three meiotic products are of this type
  33. prophase
    mitotic phase during which chromatin condenses so that chromosomes appear; chromosomes are scattered
  34. secondary oocyte
    in oogenesis, the functional product of meiosis I; becomes the egg
  35. sister chromatids
    one of two genetically identical chromosomal units that are the result of DNA replication and are attached to each other at the centromere
  36. spermatogenesis
    production of sperm in males by the process of meiosis and maturation
  37. synapsis
    pairing of homologous chromosomes during prophase I of meiosis I
  38. syndrome
    group of symptoms that appear together and tend to indicate the presence of a particular disorder
  39. telophase
    mitotic phase during which daughter chromosomes are located at each pole
  40. translocation
    movement of a chromosomal segment from one chromosome to another non homologous, leading to abnormalities; down syndrome
  41. trisomy
    one more chromosome than usual
  42. zygote
    diploid cell formed by the union of sperm and egg; the product of fertilization
Card Set
bio ch 18