Chapter 12- Cell Cycle

a double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis

the centralized region joining two sister chromatids

material present in the cytoplasm of all eukaryotic cells, important during cell division; the microtubule-organizing center

a critical control point in the cell cycle where stop and go-ahead signals can regulate the cycle

the complex of DNA and proteins that makes up a eukaryotic chromosome. When the cell is not diving, chromatin exists as a mass of very long, thin fibers that are not visible with a light microscope

a threadlike, gene-carrying structure found in the nucleus. Each chromosome consists of one very long DNA molecule and associated proteins

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 embyonic development that converts the zygote into a ball of cells

the first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate

a regulatory protein whose concentration fluctuates cyclically

a protein kinase that is active only when attached to a particualr cyclin

the division of the cytoplasm to form two seperate daughter cells immediately after mitosis

the phenomenon observed in normal animal cells that causes them to stop dividing when they come into contact with one another

a non-dividing state in which a cell has left the cell cycle

the first growth phase of the cell cycle, consisting of the portion of interphase before DNA synthesis begins

the second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs

a haploid cell, such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote

the complete complement of an organisms genes; an organisms genetic material

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

a 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 sizes may increase. Interphase accounts for 90% of the cell cycle

a specialized region on the centromere that links each sister chromatid to the mitotic spindle

the phase of the cell cycle that includes mitosis and cytokinesis

a cancerous tumor that is invasive enough to impair the functions of one ore more organs

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

an imaginary plate during metaphase in which the centromeres of all the duplicated chromosomes are located midway between the two poles

the spread of cancer cells to locations distant from their original site

a process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, pro-metaphase, metaphase, anaphase, and telophase. Mitosis conserves chromosome number by equally allocating replicated chromosomes to each of the daughter nuclei

the phase of the cell cycle that includes mitosis and cytokinesis

an assemblage of microtubules and associated proteins that is involved in the movements of chromosomes during mitosis

maturation-promoting factor; a protein complex required for a cell to progress from later interphase to mitosis. The active form consists of cyclin and protein kinase

site where the replication of a DNA molecule begins

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 chromosome

the first stage of mitosis, in which the chromatin and the mitotic spindle begins to form, but the nucleolus and nucleus are still intact

the synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated

replicated forms of a chromosome joined together by the centromere and eventually separated during mitosis or meiosis II

any cell in a multicellular organism except a sperm or egg cell

the fifth and final stage of mitosis, in which daughter nuclei are forming and sytokinesis has typically begun

1) The conversion of a normal animal cell to a cancerous cell

2) A change in genotype and phenotype doe to the assimilation of external DNA by a cell