BIO-1120: Chapter 12

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  1. Anaphase
    the fourth stage of mitosis, in which the chromatids of each chromosome have separated and the daughter chromosomes are moving to the poles of the cell
  2. Anchorage Dependence
    the requirement that a cell must be attached to a substratum in order to initiate cell division
  3. Aster
    a radial array of short microtubules that extends from each centrosome toward the plasma membrane in an animal cell undergoing mitosis
  4. Benign Tumor
    a mass of abnormal cells with specific genetic and cellular changes such that the cells are not capable of surviving at a new site and generally remain at the site of the tumor's origin
  5. Binary Fission
    a method of asexual reproduction by "division in half"; in prokaryotes, binary fission does not involve mitosis, but in single-celled eukaryotes that undergo binary fission, mitosis is part of the process
  6. Cell Cycle
    an ordered sequence of events in the life of a cell, from its origin in the division of a parent cell until its own division into two; the eukaryotic cell cycle is composed of interphase (including G1, S, and G2 subphases) and M phase (including mitosis and cytokinesis)
  7. Cell Cycle Control System
    a cyclically operating set of molecules in the eukaryarotic cell that both triggers and coordinates key events in the cell cycle
  8. Cell Division
    the reproduction of cells
  9. Cell Plate
    a membrane-bounded, flattened sac located at the midline of a dividing plant cell, inside which the new cell wall forms during cytokinesis
  10. Centromere
    in a duplicated chromosome, the region on each sister chromatid where it is most closely attached to the other chromatid by proteins that bind to the centromeric DNA; other proteins condense the chromatin in that region, so it appears as a narrow "waist" on the duplicated chromosome; (an unduplicated chromosome has a single centromere, identified by the proteins bound there)
  11. Centrosome
    a structure present in the cytoplasm of animal cells that functions as a microtubule-organizing  center and is important during cell division; a centrosome has two centrioles
  12. Checkpoint
    a control point in the cell cycle where stop and go-ahead signals can regulate the cycle
  13. Chromatin
    the complex of DNA and proteins that makes up eukaryotic chromosomes; when the cell is not dividing, chromatin exists in its dispersed form, as a mass of very long, thin fibers that are not visible with a light microscope
  14. Chromosome
    a cellular structure consisting of one DNA molecule and associated protein molecules; (in some contexts, such as genome sequencing, the term may refer to the DNA alone) a eukaryotic cell typically has multiple, linear chromosomes, which are located in the nucleus; a prokaryotic cell often has a single, circular chromosome, which is found in the nucleoid, a region that is not enclosed by a membrane
  15. Cleavage
    (1) the process of cytokinesis in animal cells, characterized by pinching of the plasma membrane (2) the succession of rapid cell divisions without significant growth during early embryonic development that converts the zygote to a ball of cells
  16. Cleavage Furrow
    the first sign of cleavage in an animal cell; a shallow groove around the cell in the cell surface near the old metaphase plate
  17. Cyclin
    a cellular protein that occurs in a cyclically fluctuating concentration and that plays an important role in regulating the cell cycle
  18. Cyclin-Dependent Kinase (CDK)
    a protein kinase that is active only when attached to a particular cyclin
  19. Cytokinesis
    the division of the cytoplasm to form two separate daughter cells immediately after mitosis, meiosis I, or meiosis II
  20. Density-Dependent Inhibition
    the phenomenon observed in normal animal cells that causes them to stop dividing when they come into contact with one another
  21. Gamete
    a haploid reproductive cell, such as an egg or sperm; gametes unite during sexual reproduction to produce a diploid zygote
  22. Genome
    the genetic material of an organism or virus; the complete complete complement of an organism's or virus's genes along with its noncoding nucleic acid sequences
  23. G0 Phase
    a nondividing state occupied by cells that have left the cell cycle, sometimes reverisbly
  24. G1 Phase
    the first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins
  25. G2 Phase
    the second gap, or growth phase, of the cell cycle, consisting of the portion of interphase after DNA synthesis begins
  26. Growth Factor
    (1) a protein that must be present in the extracellular environment (culture medium or animal body) for the growth and normal development of certain types of cells; (2) a local regulator that acts on the nearby cells to stimulate cell proliferation and differentiation
  27. Interphase
    ithe period in the cell cycle when the cell is not dividing; during interphase, cellular metabolic activity is high, chromosomes and organelles are duplicated, and cell size may increase; interphase often accounts for about 90% of the cell cycle
  28. Kinetochore
    a structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindle
  29. Malignant Tumor
    a cancerous tumor containing cells that have significant genetic and cellular changes and are capable of invading and surviving in new sites; malignant tumors can impair the functions of one or more organs
  30. Metaphase
    the third stage of mitosis, in which the spindle is complete and the chromosomes, attached to the microtubules at their kinetochores, are all aligned at the metaphase plate
  31. Metaphase Plate
    an imaginary structure located at a plane midway between the two poles of a cell in metaphase on which the centromeres of all the duplicated chromosomes are located
  32. Metastasis
    the spread of cancer cells to locations distant from their original site
  33. Mitosis
    a process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telephase; mitosis conserves chromosome number by allocating replicated chromosomes equally to each of the daughter nuclei
  34. Mitotic (M) Phase
    the phase of the cell cycle that includes mitosis and cytokinesis
  35. Mitotic Spindle
    an assemblage of microtubules and associated proteins that is involved in the movement of chromosomes during mitosis
  36. MPF
    Maturation-promoting factor (or M-phase-promoting factor); a protein complex required for a cell to progress from late interphase to mitosis; the active form consisting of cyclin and a protein kinase
  37. Origin of Replication
    site where the replication of DNA molecule begins, consisting of a specific sequence of nucleotides
  38. Prometaphase
    the second stage of mitosis, in which the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the chromosomes
  39. Prophase
    the first stage of mitosis, in which the chromatin condenses into discrete chromosomes visible with a light microscope, the mitotic spindle begins to form, and the nucleolus disappears but the nucleus remains intact
  40. Sister Chromatid
    two copies of a duplicated chromosome attached to each other by proteins at the centromere and, sometimes, along the arms; while joins, two sister chromatids make up one chromosome; chromatids are eventually separated during mitosis or meiosis II
  41. Somatic Cells
    any cell in a multicellular organism except a sperm or egg or their precursors
  42. S Phase
    the synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated
  43. Telophase
    the fifth and final stage of mitosis, in which daughter nuclei are forming and cytokinesis has typically begun
  44. Transformation
    (1) the conversion of a normal cell into a cell that is able to divide indefinitely in culture, thus behaving like a cancer cell; (malignant transformation may also describe the series of changes in a normal cell in an organism that change it into a malignant (cancerous) cell); (2) a change in genotype and phenotype due to the assimilation of external DNA by a cell; when the external DNA is from a member of a different species, transformation results in horizontal gene transfer
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BIO-1120: Chapter 12
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