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Mitosis ch12
mitosis
Question | Answer |
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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. |
anchorage dependence | The requirement that to divide, a cell must be attached to the substratum. |
aster | A radial array of short microtubules that extends from each centrosome toward the plasma membrane in a cell undergoing mitosis. |
benign tumor | A mass of abnormal cells that remains at the site of origin. |
binary fission | The type of cell division by which prokaryotes reproduce. Each dividing daughter cell receives a copy of the single parental chromosome. |
cell cycle | An ordered sequence of events in the life of a eukaryotic cell, from its origin in the division of a parent cell until its own division into two; composed of the M, G1, S, and G2 phases. |
cell cycle control system | A cyclically operating set of molecules in the cell that triggers and coordinates key events in the cell cycle. |
cell division | The reproduction of cells. |
cell plate | A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis. |
centromere | The centralized region joining two sister chromatids. |
centrosome | Material present in the cytoplasm of all eukaryotic cells, important during cell division; the microtubule-organizing center. |
checkpoint | A critical control point in the cell cycle where stop and go-ahead signals can regulate the cycle. |
chromatin | The complex of DNA and proteins that makes up a eukaryotic chromosome. |
chromosome | A threadlike, gene-carrying structure found in the nucleus. Each chromosome consists of one very long DNA molecule and associated proteins |
cleavage | The process of cytokinesis in animal cells, characterized by pinching of the plasma membrane; specifically, the succession of rapid cell divisions without growth during early embryonic development that converts the zygote into a ball of cells. |
cleavage furrow | The first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate. |
cyclin | A regulatory protein whose concentration fluctuates cyclically. |
cytokinesis | The division of the cytoplasm to form two separate daughter cells immediately after mitosis. |
density-dependent inhibition | The phenomenon observed in normal animal cells that causes them to stop dividing when they come into contact with one another. |
G0 phase | A nondividing state in which a cell has left the cell cycle. |
G1 phase | The first growth phase of the cell cycle, consisting of the portion of interphase before DNA synthesis begins. |
G2 phase | The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs. |
gamete | A haploid cell, such as an egg or sperm. |
genome | The complete complement of an organism’s genes; an organism’s genetic material. |
growth factor | A protein that must be present in the extracellular environment for the growth and normal development of certain types of cells; a local regulator that acts on nearby cells to stimulate cell proliferation and differentiation |
interphase | The period in the cell cycle when the cell is not dividing.cellular metabolic activity is high, chromosomes and organelles are duplicated, and cell size may increase. |
kinetochore | A specialized region on the centromere that links each sister chromatid to the mitotic spindle. |
M phase | mitotic(M) phase. |
malignant tumor | A cancerous tumor that is invasive enough to impair the functions of one or more organs. |
meiosis | A two-stage type of cell division in sexually reproducing organisms that results in cells with half the chromosome number of the original cell. |
metaphase | The third stage of mitosis, in which the spindle is complete and the chromosomes, attached to microtubules at their kinetochores, are all aligned at the metaphase plate. |
metaphase plate | An imaginary plane during metaphase in which the centromeres of all the duplicated chromosomes are located midway between the two poles. |
metastasis | The spread of cancer cells to locations distant from their original site. |
mitosis | A process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase.conserves chromosome number by equally allocating replicated chromosomes to each of the daughter nuclei |
mitotic (M) phase | The phase of the cell cycle that includes mitosis and cytokinesis. |
mitotic spindle | An assemblage of microtubules and associated proteins that is involved in the movements of chromosomes during mitosis. |
MPF | Maturation-promoting factor (M-phase-promoting factor); a protein complex required for a cell to progress from late interphase to mitosis. The active form consists of cyclin and a protein kinase. |
origin of replication | Site where the replication of a DNA molecule begins. |
prometaphase | The second stage of mitosis, in which discrete chromosomes consisting of identical sister chromatids appear, the nuclear envelope fragments, and the spindle microtubules attach to the kinetochores of the chromosomes. |
prophase | The first stage of mitosis, in which the chromatin is condensing and the mitotic spindle begins to form, but the nucleolus and nucleus are still intact. |
S phase | The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated. |
sister chromatids | Replicated forms of a chromosome joined together by the centromere and eventually separated during mitosis or meiosis II. |
somatic cell | Any cell in a multicellular organism except a sperm or egg cell. |
telophase | The fifth and final stage of mitosis, in which daughter nuclei are forming and cytokinesis has typically begun. |
transformation | (1) The conversion of a normal animal cell to a cancerous cell. (2) A change in genotype and phenotype due to the assimilation of external DNA by a cell. |