[9] Vocabulary - The Cell Cycle

Question 1

prometaphase

Answer 1

the second stage of mitosis, in which the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the chromosomes.

Question 2

prophase

Answer 2

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

Question 3

cell division

Answer 3

the reproduction of cells

Question 4

malignant tumor

Answer 4

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.

Question 5

metastasis

Answer 5

the spread of cancer cells to locations distant from their original site (breast cancer developing into brain cancer)

Question 6

cell cycle

Answer 6

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 (G1, S, G2) and M phase (inclduing mitosis and cytokinesis)

Question 7

chromosome

Answer 7

a cellular structure consisting of one DNA molecule and associated protein molecules. 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.

Question 8

cleavage

Answer 8

(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

Question 9

cleavage furrow

Answer 9

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

Question 10

sister chromatids

Answer 10

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

Question 11

cell plate

Answer 11

A membrane-bounded, flattened sac located at the midline of a dividing plant cell, inside which the new cell wall forms during cytokinesis.

Question 12

gamete

Answer 12

A haploid reproductive cell, such as an egg or sperm, that is formed by meiosis or is the descendant of cells formed by meiosis. Gametes unite during sexual reproduction to produce a diploid zygote

Question 13

binary fission

Answer 13

A method of asexual reproduction in single-celled organisms in which the cell grows to roughly double its size and then divides into two cells. In prokaryotes, binary fission does not involve mitosis, but in single-celled eukaryotes that undergo binary fission, mitosis is part of the process.

Question 14

metaphase plate

Answer 14

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.

Question 15

mitosis

Answer 15

A process of nuclear division in eukaryotic cells conventionally divided into five stagesprophase, prometaphase, metaphase, anaphase, and telophase. Mitosis conserves chromosome number by allocating replicated chromosomes equally to each of the daughter nuclei.

Question 16

mitotic (M) phase

Answer 16

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

Question 17

G2 phase

Answer 17

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

Question 18

cytokinesis

Answer 18

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

Question 19

growth factor

Answer 19

(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.

Question 20

cell cycle control system

Answer 20

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

Question 21

centromere

Answer 21

In a duplicated chromosome, the region on each sister chromatid where it is most closely attached to its sister 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.)

Question 22

checkpoint

Answer 22

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

Question 23

centrosome

Answer 23

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.

Question 24

benign tumor

Answer 24

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.

Question 25

genome

Answer 25

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.

Question 26

transformation

Answer 26

(1) The process by which a cell in culture acquires the ability to divide indefinitely, similar to the division of cancer cells.
(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.

Question 27

mitotic spindle

Answer 27

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

Question 28

chromatin

Answer 28

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.

Question 29

somatic cell

Answer 29

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

Question 30

metaphase

Answer 30

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.

Question 31

S phase

Answer 31

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

Question 32

telophase

Answer 32

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

Question 33

anchorage dependence

Answer 33

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

Question 34

G1 phase

Answer 34

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

Question 35

density-dependent inhibition

Answer 35

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

Question 36

interphase

Answer 36

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 often accounts for about ‘0% of the cell cycle.

Question 37

kinetochore

Answer 37

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

Question 38

origin of replication

Answer 38

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

Question 39

anaphase

Answer 39

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.

Question 40

G0 phase

Answer 40

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