Deck 24: The Cell Cycle and Mitosis

Question 1

Cyclins modulate the progression of cells through the cell cycle by directly

A)activating G proteins.
B)phosphorylating growth factor receptors.
C)activating protein kinases that are critical regulators of cell division.
D)degrading histones.
E)turning on genes necessary for DNA replication.

Answer 1

C

Question 2

Chromosome condensation indicates a cell has entered

A)prophase.
B)prometaphase.
C)metaphase.
D)anaphase.
E)telophase.

Answer 2

B

Question 3

The generation time for a particular cell type is the time it takes a cell to

A)grow to twice its original size.
B)replicate DNA during S phase.
C)progress through M phase.
D)progress through a complete cell cycle.
E)transition from G0 to G1.

Answer 3

D

Question 4

Each of the following is true about anaphase except

A)anaphase is the shortest stage of the mitosis.
B)during anaphase A,each chromosome is pulled to its respective pole as its kinetochore microtubules shorten.
C)during anaphase B,the spindle poles are pushed further apart as interpolar microtubules lengthen.
D)anaphase B may be coincident with or follow anaphase A,depending on the cell type.
E)All of the above are true.

Question 5

A population of T cells was stimulated to proliferate in response to a particular antigen.A sample of 1000 stimulated cells was analyzed by fluorescence-activated cell sorting (FACS)for total DNA content.Of the 1000 cells,400 had a 2n amount of DNA,200 had a 4n amount of DNA,and the remaining 400 cells had between a 2n and 4n amount of DNA.Additional immunofluorescence analysis revealed that 200 of the cells were in various stages of M phase and that M phase lasted 2 hours.What is the total length of the cell cycle?

A)8 hours
B)12 hours
C)18 hours
D)20 hours
E)24 hours

Question 6

Which of the following recruits proteins to form a kinetochore at the centromere?

A)kinesin
B)cytoplasmic dynein
C)CENP-A
D)cohesin
E)APC

Question 7

Animal cell centrosome MTOCs contain

A)condensins.
B)cyclin-Cdk.
C)centrioles.
D)mitochondria.
E)phragmoplasts.

Question 8

A eukaryotic cell G2-M checkpoint assesses the status of

A)DNA replication.
B)chromosome attachment to kinetochore microtubules.
C)nutrient abundance.
D)mitotic cyclin degradation.
E)the presence of growth factors.

Question 9

The appearance that the spindle and sister chromatids are inactive at metaphase is misleading because

A)the sister chromatids are completing replication at numerous replicons.
B)the sister chromatids are signaling reformation of the nuclear envelope.
C)each sister chromatid is assembling a kinetochore.
D)each sister chromatid is being pulled toward its respective pole.
E)the sister chromatids are decondensing.

Question 10

Which of the following correctly orders the stages of mitosis?

A)prophase - anaphase - prometaphase - metaphase - telophase
B)telophase - prometaphase - prophase - metaphase - anaphase
C)prometaphase - metaphase - anaphase - prophase - telophase
D)prophase - prometaphase - metaphase - anaphase - telophase
E)anaphase - prometaphase - metaphase - prophase - telophase

Question 11

A mutant cell in which sister chromatids get torn apart rather than separating correctly at anaphase most likely is deficient in

A)mitotic Cdk.
B)mitotic cyclin.
C)APC.
D)topoisomerase II.
E)helicase loaders.

Question 12

Cells grow primarily during which of the following cell-cycle phases?

A)G0
B)G1
C)G2
D)M
E)S

Question 13

In an adult human stem cell that has a total of 48 chromosomes,how many chromatids are present at prophase of mitosis?

A)12
B)24
C)48
D)72
E)96

Question 14

Genomic DNA is replicated during which of the following cell-cycle phases?

A)G0
B)G1
C)G2
D)M
E)S

Question 15

Which of the following occurs during prometaphase (late prophase)?

A)continuous kinetochore microtubule shortening
B)Rho-stimulated formation of a contractile ring
C)centrosome duplication
D)APC targeting of securin destruction
E)nuclear envelope fragmentation

Question 16

In the cell cycle,a mitotic Cdk is present during

A)G1.
B)G2.
C)M)
D)S)
E)All of the above phases are present in the cell cycle.

Question 17

Each of the following is an activity of a microtubule motor protein during mitosis except

A)shortening kinetochore microtubules.
B)pulling kinetochore microtubules in at centrosomes.
C)pushing interpolar microtubules for anaphase B.
D)pulling astral microtubules toward the cell cortex.
E)All of the above are activities of microtubule motors.

Question 18

When early G1 phase cells are fused with S-phase cells using polyethylene glycol (PEG),which of the following events would you expect to be induced?

A)cytokinesis in the S-phase cells
B)condensation of chromosomes in the S-phase cells
C)DNA replication in the G1 cells
D)transition to G0 in the G1 cells
E)spindle fiber formation in the G1 cells

Question 19

Each of the following provides evidence that kinetochore microtubule shortening is directly involved in anaphase A chromosome movement to a pole except

A)Stabilization of microtubules with the drug paclitaxel stops chromosome movement to a pole.
B)Treatment that accelerates microtubule depolymerization causes chromosomes to move toward the poles more quickly.
C)Antibody inhibition of kinesin depolymerization of kinetochore microtubules interferes with chromosome movement to a pole.
D)Laser bleaching of labeled kinetochore microtubules indicates they shorten at the kinetochore as the chromosome moves toward a pole.
E)All of the above are evidence that kinetochore microtubule shortening is directly involved in anaphase A chromosome movement to a pole.

Question 20

A particular haploid strain of yeast contains a temperature-sensitive mutation in its cdc2 gene resulting in no functional Cdc2 protein at the nonpermissive temperature.At the nonpermissive temperature,each of the following events would fail to occur at the appropriate cell cycle stage except

A)replication of DNA.
B)fragmentation of the nuclear envelope.
C)condensation of chromosomes.
D)appearance of the mitotic spindle.
E)prevention of fusion of chromosome ends.

Question 21

Mitotic Cdk-cyclin is active when it is

A)singly phosphorylated.
B)acetylated.
C)doubly phosphorylated.
D)doubly methylated.
E)cleaved by proteases.

Question 22

Dividing adult eukaryotic cells spend most of their time in which of the following?

A)metaphase
B)prophase
C)telophase
D)interphase
E)anaphase

Question 23

Each of the following is involved in DNA replication licensing during S phase except

A)geminin.
B)ORC.
C)MCM proteins.
D)helicase loaders.
E)CENP-A.

Question 24

Each of the following statements regarding CD95-stimulated programmed cell death is true except

A)CD95 ligand binding with CD95 receptor stimulates recruitment of adaptor proteins.
B)adaptor proteins stimulate the PI3K-Akt pathway.
C)recruitment to sites of receptor clustering activates initiator caspase (caspase 8)activity.
D)initiator caspases proteolytically cleave executioner procaspases (procaspase 3).
E)a caspase cascade results in the cleavage of many types of proteins in the target cell.

Question 25

In the cell cycle,controlled degradation of regulatory proteins occurs via the

A)P₄₅₀-protease pathway.
B)cyclin-Cdk pathway.
C)ubiquitin-proteasome pathway.
D)kinase inhibition pathway.
E)PI3K-Akt pathway.

Question 26

Phosphorylation of ________ is directly required for chromosome condensation.

A)condensin
B)mitotic cyclin
C)securin
D)ubiquitin ligase
E)histone H3

Question 27

The multiple sites of DNA replication along eukaryotic chromosomes are known as

A)replicons.
B)centromeres.
C)telomeres.
D)plasmodesmata.
E)targets of rapamycin.

Question 28

During the cell cycle,MPF activity

A)peaks in S and decreases in G2.
B)peaks in G2 and decreases in G1.
C)peaks in M and decrease in M.
D)peaks in M and decreases at the restriction point.
E)peaks in G1 and decreases in G2.

Question 29

Each of the following is involved in regulating mitotic Cdk activity except

A)cyclin synthesis and degradation.
B)Cdk synthesis and degradation.
C)Cdk phosphorylation.
D)Cdk dephosphorylation.
E)All are involved in regulating mitotic Cdk activity.

Question 30

The mechanism by which DNA is licensed to replicate only once during each S phase involves

A)CENP-A binding to CEN DNA.
B)MCM proteins binding only to CEN DNA.
C)MCM proteins binding only to replicated DNA.
D)MCM proteins binding only to nonreplicated DNA.
E)MCM proteins binding to both replicated and nonreplicated DNA.

Question 31

Each of the following would inhibit cell progression through the cell cycle except

A)DNA damage during replication.
B)kinase phosphorylation of mitotic Cdk.
C)APC activity during M phase.
D)unphosphorylated Retinoblastoma activity during G1.
E)TGFβ signaling.

Question 32

All of the following participate in apoptosis except

A)caspases.
B)death signals.
C)mitochondria.
D)Bcl-2.
E)APC ubiquitin ligase activity.

Question 33

The cell-cycle phase that varies most in duration in various eukaryotic adult cell types is

A)M.
B)G1.
C)S)
D)G2.
E)G0.

Question 34

The epidermal growth factor-Ras signaling pathway stimulates increased expression of each of the following except

A)MAPK.
B)Jun.
C)Fos.
D)Myc.
E)The pathway turns on expression of all of the above.

Question 35

Raf is to MEK,as MEK is to

A)Ras.
B)PI3K.
C)MAPK.
D)Cdk.
E)Akt.

Question 36

Which of the following is eliminated in rapidly dividing embryonic cells that get smaller with each cell division?

A)G1 phase
B)S phase
C)G2 phase
D)M-phase chromosome separation
E)M-phase cytokinesis

Question 37

In a dividing fruit fly cell lacking components of the centralspindlin complex,

A)the nuclear envelope remains intact.
B)the centrosome fails to duplicate.
C)sister chromatids fail to separate for anaphase A.
D)no anaphase B occurs.
E)cytokinesis begins,but the cleavage furrow regresses.

Question 38

Which of the following families of proteins plays a central role in regulating the assembly and activation of the contractile ring?

A)Rho
B)Cdk
C)Polo
D)Aurora
E)Cdk activating kinase

Question 39

Each of the following is involved in plants cell cytokinesis except

A)phragmoplast alignment of Golgi-derived vesicles in the center of the dividing cell.
B)fusion of Golgi-derived vesicles to form the cell plate.
C)assembly of vesicle noncellulose components to form the primary cell wall.
D)abscission of the cell into two cells.
E)All are involved in plant cytokinesis.

Question 40

A protein on the surface of cytotoxic lymphocytes can elicit self-destruct mechanisms in target cells by interacting with

A)TGFβ receptors.
B)Death receptors.
C)EGF receptors.
D)Bcl-2.
E)procaspase 3.

Question 41

Interaction between importin and the ________ leads to the release of importin-bound proteins that promote spindle microtubule assembly.

Question 42

Which of the following pathways is affected in ced mutants of C.elegans?

A)mitogen signaling
B)apoptosis
C)cell cycle
D)terminal differentiation
E)stem cell division

Question 43

What type of protein is PTEN,which is mutated in 50% of prostate cancers?

A)kinase
B)phosphatase
C)growth factor receptor
D)G protein
E)ubiquitin ligase

Question 44

A centromere contains repeated DNA sequences known as ________.

Question 45

Bacteria use the protein ________,which is structurally related to tubulin,to form a ring at the site where the two daughter cells will separate.

Question 46

Which of the following is the correct order of the pathway by which activation of PI3-kinase stimulates cell division?

A)PIP₃ formation-Akt phosphorylation-TOR activation-Rheb activation
B)PIP₃ formation-TOR activation-Rheb activation-Akt phosphorylation
C)Akt phosphorylation-TOR activation-Rheb activation-PIP₃ formation
D)PIP₃ formation-Akt phosphorylation-Rheb activation-TOR activation
E)Akt phosphorylation-PIP₃ formation-TOR activation-Rheb activation

Question 47

Terminally differentiated cells such as neurons are in the phase of the cell cycle known as ________.

Question 48

Proteins bound to CEN sequences form a complex known as the ________.

Question 49

Movement of sister chromatids back and forth during prometaphase is known as ________.

Question 50

Following DNA replication,the attached copies of each chromosome are called ________.

Question 51

Mitotic Cdk phosphorylates DNA repair proteins to prevent joining of ________ during mitosis.

Question 52

Rapidly dividing embryonic cells shorten S-phase duration by increasing the number of ________.

Question 53

Each of the following occurs during apoptosis of a cell except

A)flipping phosphatidylserine to the outer leaflet of the plasma membrane.
B)DNase fragmentation of DNA.
C)bleb formation.
D)rupture of the cell,releasing cytoplasmic contents.
E)formation of apoptotic bodies.

Question 54

Cell growth is linked to the cell cycle by a protein kinase known as ________,so that cells can divide without getting progressively smaller.

Question 55

DNA replication of linear chromosomes is initiated at multiple sites known as ________.

Question 56

Cell cycle studies have been facilitated by ________,a technique that allows rapid analysis and sorting of thousands or millions of cells.

Question 57

The final separation of two daughter cells at the end of cytokinesis in animals is known as ________.

Question 58

Each of the following involves apoptosis except

A)removing webbing between digits during development.
B)decreasing neurons during brain development.
C)destroying pathogen-infected cells.
D)removing white blood cells at the end of their life span.
E)generating a cancerous tumor.

Question 59

Each of the following is true about cytochrome c in apoptosis except

A)It is released from mitochondria.
B)It stimulates Ca²⁺ release from mitochondria.
C)It stimulates Ca²⁺ release from the endoplasmic reticulum.
D)It activates Rheb.
E)It associates with Apaf1 to form an apoptosome.

Question 60

M phase involves two overlapping events known as ________ and ________.

Question 61

Caspases are produced as inactive precursors known as ________.

Question 62

Starting with a diploid cell (2n = 4),illustrate the phases of mitosis with emphasis on the movement of chromosomes.

Question 63

Specific control points that are sensitive to extracellular conditions regulate G1-S transition in eukaryotic cells.Passage through the yeast Start point requires sufficient ________,whereas passage through the animal cell restriction point requires the presence of ________.

Question 64

Epidermal growth factor is a mitogen,because it stimulates cells to divide.(1)Explain the role of Ras in epidermal growth factor signaling that results in cell division.(2)Design two experiments to prove that Ras is a key player in the EGF-activated pathway.(3)What assay other than cell division could you use to assess whether the EGF-Ras-MAPK pathway has been activated?

Question 65

You are working with a mixed population of cells that includes some cells expressing CD95 on their surfaces.Design an experimental protocol using Fluorescence-Activated Cell Sorting (FACS)to determine how many CD95-expressing cells are dividing at any given time.

Question 66

As the most junior member of a lab,you are tasked with generating cell lines that accumulate DNA damage to investigate how random mutations affect transformation of cells into cancer cells.You decide to mutate proteins in the p53 pathway.Which three proteins would you mutate? Explain your reasoning.