Bio Ch. 12 - Mitosis

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49 terms · All vocab words for Ch. 12 Mitosis.

actin

A globular protein that links into chains, two of which twist helically about each other, forming microfilaments (actin filaments) in muscle and other kinds of cells.

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 a cell must be attached to a substratum in order to divide.

aster

A radial array of short microtubules that extends from each centrosome toward the plasma membrane in an animal cell undergoing mitosis.

Bacteria

One of two prokaryotic domains, the other being Archaea.

actin

A globular protein that links into chains, two of which twist helically about each other, forming microfilaments (actin filaments) in muscle and other kinds of cells.

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.

aster

A radial array of short microtubules that extends from each centrosome toward the plasma membrane in an animal cell undergoing mitosis.

Bacteria

One of two prokaryotic domains, the other being Archaea.

benign tumor

A mass of abnormal cells that remains at the site of its origin.

binary fission

A method of asexual reproduction by "division in half." In prokaryotes, it does not involve mitosis; but in single-celled eukaryotes that undergo it, mitosis is part of the process.

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).

cell cycle control system

A cyclically operating set of molecules in the eukaryotic cell that both triggers and coordinates key events in the cell cycle.

cell plate

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

centromere

The specialized region of the chromosome where two sister chromatids are most closely attached.

centrosome

Structure present in the cytoplasm of animal cells, important during cell division; functions as a microtubule-organizing center. A centrosome has two centrioles.

checkpoint

A 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. When the cell is not dividing, it exists in its dispersed form, as a mass of very long, thin fibers that are not visible with a light microscope.

chromosome

cellular structure carrying genetic material, found in the nucleus of eukaryotic cells. Each chromosome consists of one very long DNA molecule and associated proteins. (A bacterial [this word] usually consists of a single circular DNA molecule and associated proteins. It is found in the nucleoid region, which is not membrane bounded.)

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.

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 cellular protein that occurs in a cyclically fluctuating concentration and that plays an important role in regulating the cell cycle.

Cdk (cyclin-dependent kinase)

A protein kinase that is active only when attached to a particular cyclin.

cytokinesis

The division of the cytoplasm to form two separate daughter cells immediately after mitosis, meiosis I, or meiosis II.

density-dependent inhibition

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

Down syndrome

A human genetic disease caused by the presence of an extra chromosome 21: characterized by mental retardation and heart and respiratory defects.

G0 phase

A nondividing state occupied by cells that have left the cell cycle.

G1 phase

The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.

G2 phase

The second gap, or growth phase, of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.

gamete

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

genome

The genetic material of an organism or virus; the complete complement of an organism's or virus's genes along with its noncoding nucleic acid sequences.

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 nearby cells to stimulate cell proliferation and differentiation.

interphase

The 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 accounts for 90% of the cell cycle.

kinetochore

A structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindle.

malignant tumor

A cancerous tumor that is invasive enough to impair the functions of one or more organs.

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 midway between the two poles of a cell in metaphase on which the centromeres of all the duplicated chromosomes are located.

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. Mitosis conserves chromosome number by allocating replicated chromosomes equally 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.

origin of replication

Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides.

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 condenses, the mitotic spindle begins to form, and the nucleolus disappears, but the nucleus remains intact.

S phase

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

sister chromatid

Either of two copies of a duplicated chromosome attached to each other by proteins at the centromere and, sometimes, along the arms. While joined, they make up one chromosome; they are eventually separated during mitosis or meiosis II.

somatic cell

Any cell in a multicellular organism except a sperm or egg.

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.

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