Chapter 12

Question 1

The reproduction of cells.

Answer 1

Cell Division

Question 2

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 ____ _____ is composed of interphase (including G¹, S, and G² subphases) and M phase (including mitosis and cytokinesis).

Answer 2

Cell Cycle

Question 3

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.

Answer 3

Genome

Question 4

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

Answer 4

Chromosome

Question 5

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

Answer 5

Somatic Cell

Question 6

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

Answer 6

Gamete

Question 7

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

Answer 7

Sister Chromatid

Question 8

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

Answer 8

Centromere

Question 9

The complex of DNA and proteins that makes up a eukaryotic chromosome. When the cell is not dividing, _______ exists in its dispersed form, as a mass of very long, thin fibers that are not visible with a light microscope.

Answer 9

Chromatin

Question 10

A process of nuclear division in eukaryotic cells conventionally divided into 5 stages: prophase, prometaphase, metaphase, anaphase, and telophase. _______ conserves chromosome number by allocating replicated chromosomes equally to each of the daughter nuclei.

Answer 10

Mitosis

Question 11

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

Answer 11

Cytokinesis

Question 12

A modified type of cell division in sexually reproducing organisms consisting of two rounds of cell division but only one round of DNA replication. It results in cells with half the number of chromosome sets as the original cell.

Answer 12

Meiosis

Question 13

The phase of the cell cycle that includes mitosis and cytokinesis.

Answer 13

Mitotic (M) Phase

Question 14

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. Accounts for 90% of the cell cycle.

Answer 14

Interphase

Question 15

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

Answer 15

G₁ Phase

Question 16

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

Answer 16

S phase

Question 17

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

Answer 17

G₂Phase

Question 18

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.

Answer 18

Prophase

Question 19

The second stage of mitosis, in which the discrete chromosomes consisting of identical sister chromatids appear, the nuclear envelope fragments, and the spindle microtubules attach to the kinetochores of the chromosomes.

Answer 19

Prometaphase

Question 20

The third stage of mitosis, in which the spindle is complete and the chromosomes, attached to microtubues at their kinetochores, are all aligned at the metaphase plate.

Answer 20

Metaphase

Question 21

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.

Answer 21

Anaphase

Question 22

The fifth and final stage of mitosis, in which daughter nuclei are forming and cytokinesis has typically begun.

Answer 22

Telophase

Question 23

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

Answer 23

Mitotic Spindle

Question 24

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

Answer 24

Centrosome

Question 25

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

Answer 25

Kinetochore

Question 26

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

Answer 26

Metaphase Plate

Question 27

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

Answer 27

Aster

Question 28

The process of cytokinesis in animal cells, characterized by pinching of the plasma membrane.

Answer 28

Cleavage

Question 29

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

Answer 29

Cleavage Furrow

Question 30

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

Answer 30

Cell Plate

Question 31

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

Answer 31

Binary Fissioin

Question 32

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

Answer 32

Origin of Replication

Question 33

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

Answer 33

Cell Cycle Control System

Question 34

A control point in the cell cycle where stop and go-ahead signals can regulate the cycle.

Answer 34

Checkpoint

Question 35

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

Answer 35

Cyclin

Question 36

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

Answer 36

Cyclin-Dependent Kinase (Cdk)

Question 37

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.

Answer 37

MPF

Question 38

(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.

Answer 38

Growth Factor

Question 39

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

Answer 39

Density-Dependent Inhibition

Question 40

The requirement that a cell must be attached to a substratum in order to divide.

Answer 40

Anchorage Dependence

Question 41

(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.

Answer 41

Transformation

Question 42

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

Answer 42

Benign Tumor

Question 43

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

Answer 43

Malignant Tumor

Question 44

The spread of cancer cells to locations distant from their original site.

Answer 44

Metastasis