Kapitel 18

Question 1

Stage of mitosis during which the two sets of chromosomes separate and are pulled toward opposite ends of the dividing cell.

Answer 1

anaphase

Question 2

A protein complex that triggers the separation of sister chromatids and orchestrates the carefully timed destruction of proteins that control progress through the cell cycle; the complex catalyzes the ubiquitylation of its targets.

Answer 2

anaphase-promoting complex (APC)

Question 3

A tightly controlled form of programmed cell death that allows cells that are unneeded or unwanted to be eliminated from an adult or developing organism.

Answer 3

apoptosis

Question 4

Star-shaped array of microtubules emanating from a centrosome or from a pole of a mitotic spindle.

Answer 4

aster

Question 5

Related group of intracellular proteins that regulates apoptosis; some family members promote cell death - others inhibit it.

Answer 5

Bcl2 family

Question 6

The symmetrical attachment of a sister chromatid pair on the mitotic spindle - such that one chromatid in the duplicated chromosome is attached to one spindle pole and the other is attached to the opposite pole.

Answer 6

bi-orientation

Question 7

A family of proteases that - when activated - mediates the destruction of the cell by apoptosis.

Answer 7

caspase

Question 8

Regulatory protein that blocks the assembly or activity of cyclin–Cdk complexes - delaying progression primarily through the G1 and S phases of the cell cycle.

Answer 8

Cdk inhibitor protein

Question 9

Network of regulatory proteins that govern the orderly progression of a eukaryotic cell through the stages of cell division.

Answer 9

cell-cycle control system

Question 10

Process by which the centrosome duplicates (during interphase) and the two new centrosomes separate (at the beginning of mitosis) to form the poles of the mitotic spindle.

Answer 10

centrosome cycle

Question 11

Mechanism by which the cell-cycle control system can regulate progression through the cycle - ensuring that conditions are favorable and each process has been completed before proceeding to the next stage.

Answer 11

checkpoint

Question 12

Process by which a duplicated chromosome becomes packed into a more compact structure prior to cell division.

Answer 12

chromosome condensation

Question 13

Protein complex that holds sister chromatids together after DNA has been replicated in the cell cycle.

Answer 13

cohesin

Question 14

Protein complex that helps configure duplicated chromosomes for segregation by making them more compact.

Answer 14

condensin

Question 15

Structure made of actin and myosin filaments that forms a belt around a dividing cell - pinching it in two.

Answer 15

contractile ring

Question 16

Regulatory protein whose concentration rises and falls at specific times during the eukaryotic cell cycle; cyclins help control progression from one stage of the cell cycle to the next by binding to cyclin-dependent protein kinases (Cdks).

Answer 16

cyclin

Question 17

Enzyme that - when complexed with a regulatory cyclin protein - can trigger various events in the cell-division cycle by phosphorylating specific target proteins.

Answer 17

cyclin-dependent protein kinase (Cdk)

Question 18

Process by which the cytoplasm of a plant or animal cell divides in two to form individual daughter cells.

Answer 18

cytokinesis

Question 19

Regulatory protein that helps drive a cell through the first gap phase of the cell cycle and toward S phase.

Answer 19

G1 cyclin

Question 20

Gap 1 phase of the eukaryotic cell cycle; falls between the end of cytokinesis and the start of DNA synthesis.

Answer 20

G1 phase

Question 21

Protein complex whose activity drives the cell through the first gap phase of the cell cycle; consists of a G1 cyclin plus a cyclin-dependent protein kinase (Cdk).

Answer 21

G1-Cdk

Question 22

Regulatory protein that helps to launch the S phase of the cell cycle.

Answer 22

G1/S cyclin

Question 23

Protein complex whose activity triggers entry into S phase of the cell cycle; consists of a G1/S cyclin plus a cyclin-dependent protein kinase (Cdk).

Answer 23

G1/S-Cdk

Question 24

Gap 2 phase of the eukaryotic cell cycle; falls between the end of DNA synthesis and the beginning of mitosis.

Answer 24

G2 phase

Question 25

Extracellular signaling molecule that stimulates a cell to increase in size and mass. Examples include epidermal growth factor (EGF) and platelet-derived growth factor (PDGF).

Answer 25

growth factor

Question 26

Long period of the cell cycle between one mitosis and the next. Includes G1 phase - S phase - and G2 phase.

Answer 26

interphase

Question 27

Protein complex that assembles on the centromere of a condensed mitotic chromosome; the site to which spindle microtubules attach.

Answer 27

kinetochore

Question 28

Regulatory protein that binds to mitotic Cdk to form M-Cdk - the protein complex that triggers the M phase of the cell cycle.

Answer 28

M cyclin

Question 29

Period of the eukaryotic cell cycle during which the nucleus and cytoplasm divide.

Answer 29

M phase

Question 30

Protein complex that triggers the M phase of the cell cycle; consists of an M cyclin plus a mitotic cyclin-dependent protein kinase (Cdk).

Answer 30

M-Cdk

Question 31

Stage of mitosis in which chromosomes are firmly attached to the mitotic spindle at its equator but have not yet segregated toward opposite poles.

Answer 31

metaphase

Question 32

An extracellular signal molecule that stimulates cell proliferation.

Answer 32

mitogen

Question 33

Division of the nucleus of a eukaryotic cell.

Answer 33

mitosis

Question 34

Array of microtubules and associated molecules that forms between the opposite poles of a eukaryotic cell during mitosis and pulls duplicated chromosome sets apart.

Answer 34

mitotic spindle

Question 35

Transcription regulator that controls the cell’s response to DNA damage - preventing the cell from entering S phase until the damage has been repaired or inducing the cell to commit suicide if the damage is too extensive; mutations in the gene encoding this protein are found in many human cancers.

Answer 35

p53

Question 36

In a dividing plant cell - structure made of microtubules and membrane vesicles that guides the formation of a new cell wall.

Answer 36

phragmoplast

Question 37

A tightly controlled form of cell suicide that allows cells that are unneeded or unwanted to be eliminated from an adult or developing organism; also called apoptosis.

Answer 37

programmed cell death

Question 38

Stage of mitosis in which the nuclear envelope breaks down and duplicated chromosomes are captured by the spindle microtubules; precedes metaphase.

Answer 38

prometaphase

Question 39

First stage of mitosis - during which the duplicated chromosomes condense and the mitotic spindle forms.

Answer 39

prophase

Question 40

Regulatory protein that helps to launch the S phase of the cell cycle.

Answer 40

S cyclin

Question 41

Period during a eukaryotic cell cycle in which DNA is synthesized.

Answer 41

S phase

Question 42

Protein complex whose activity initiates DNA replication; consists of an S cyclin plus a cyclin-dependent protein kinase (Cdk).

Answer 42

S-Cdk

Question 43

Copy of a chromosome - produced by DNA replication - that remains bound to the other copy.

Answer 43

sister chromatid

Question 44

Centrosome from which microtubules radiate to form the mitotic spindle.

Answer 44

spindle pole

Question 45

Extracellular signal molecule that must be present to suppress apoptosis.

Answer 45

survival factor

Question 46

Final stage of mitosis in which the two sets of separated chromosomes decondense and become enclosed by a nuclear envelope.

Answer 46

telophase

Question 47

See anaphase-promoting complex

Answer 47

APC

Question 48

Separation of a cell into two daughter cells. In eukaryotic cells - entails the splitting of the nucleus (mitosis) closely followed by cleavage of the cytoplasm (cytokinesis).

Answer 48

cell division

Question 49

See sister chromatid

Answer 49

chromatid

Question 50

See chromosome condensation

Answer 50

condensation

Question 51

Assembly of proteins that is bound to the DNA at origins of replication in eukaryotic chromosomes throughout the cell cycle.

Answer 51

origin recognition complex (ORC)

Question 52

During cell division - the process by which duplicated chromosomes are organized and then separated into the chromosome sets that will be inherited by each of the daughter cells.

Answer 52

segregation

Question 53

Protein complex in centrosomes from which microtubules grow.

Answer 53

γ-tubulin ring