Deck 19: The Cell Cycle, Dna Replication, and Mitosis

Question 1

Which of the following families of proteins is associated with the contractile ring?

A)delta
B)alpha
C)rho
D)sigma
E)kappa

Answer 1

C

Question 2

DNA replication

A)requires a type of RNA polymerase.
B)proceeds by making two continuous strands.
C)is partially regulated by promoter/terminator sites.
D)is conservative.
E)is not edited once polymerization has occurred.

Answer 2

A

Question 3

During metaphase of mitosis, how many telomeres are present in a cell in which 2n = 12?

A)48
B)1200
C)6
D)24
E)12

Answer 3

A

Question 4

Ras is to Raf, as MEK is to

A)MAPK.
B)Ras.
C)cell growth.
D)tyrosine.
E)Cdc.

Question 5

The phase of the cell cycle that varies most in duration in various cell types is

A)M.
B)S.
C)G1.
D)G2.
E)both A and B

Question 6

The proteins most actively synthesized during the S phase of the cell cycle are

A)histones.
B)DNA polymerases.
C)cyclins.
D)rRNA proteins.
E)single- strand binding proteins.

Question 7

Using polyethylene glycol (PEG), early G1 phase cells were fused with S phase cells. Of the following events, which would you expect to be induced in the G1 cells as a result of the fusion?

A)spindle fiber formation
B)mitosis
C)condensation of chromosomes
D)cytokinesis
E)DNA replication

Question 8

In order to be active, a Cdc- cyclin needs to be

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

Question 9

A population of T cells has been stimulated to proliferate in response to a particular antigen. A sample of 1000 cells is examined microscopically in revealing that 200 of these cells are in the various stages of mitosis. Of the remaining 800 in interphase, 400 have x amount of DNA, 250 have 2x, and the remaining 150 have amounts somewhere between x and 2x. Additional analysis reveals that the G2 phase of the cell cycle lasts 2 hours. What is the total length of the cell cycle?

A)6.4 hours
B)4 hours
C)13.3 hours
D)2.5 hours
E)8 hours

Question 10

A NASA probe returned samples of rocks from the surface of Mars. From these rocks, a prokaryotic organism was isolated and remained viable under conditions similar to that of Mars. The organisms are capable of dividing to replicate themselves. An experiment was performed to determine whether the DNA replication of these organisms was semi- conservative using N15/N14 , similar to that of Mendelson and Stahl. If the method of DNA replication were conservative, after one generation one would expect to see

A)all of the DNA in the light (N14)band.
B)all of the DNA in the heavy (N15)band.
C)half of the DNA in the light band, the other half in the heavy band.
D)all of the DNA at a point midway between the heavy and light bands.
E)none of the above

Question 11

A particular strain of yeast produces strains with a mutant cdc2 gene, resulting in little to no production of the Cdc2 protein kinase. As a result, one would expect that these cells would

A)lack chromosome condensation.
B)not have the nuclear envelope disperse.
C)not enter M phase.
D)all of the above
E)none of the above

Question 12

Which enzyme is involved in proofreading during DNA replication?

A)3' to 5' endonuclease
B)5' to 3' endonuclease
C)5' to 3' exonuclease
D)DNA polymerase
E)3' to 5' exonuclease

Question 13

In a cell with a diploid number of 12, how many chromatids are present at prophase of mitosis?

A)24
B)48
C)6
D)12
E)none of the above

Question 14

A mutant strain of yeast possesses a mutation in the nda2 gene, resulting in no production of a1 tubulin. As a result, these cells would most likely

A)not enter M phase.
B)keep the nuclear membrane intact.
C)have little or no spindle formation.
D)not duplicate their chromosomes.
E)not enter S phase.

Question 15

The phase of the cell cycle associated with the doubling of the amount of DNA in the cell is

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

Question 16

Which of the following proteins is observed exclusively in association with prokaryotic DNA replication?

A)single- strand binding proteins
B)primase
C)telomerase
D)helicase
E)DNA polymerase I

Question 17

The phase of the cell cycle associated with the replication of DNA is

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

Question 18

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

A)ARS elements.
B)helicase loaders.
C)replicons.
D)multi- replication forks.
E)none of the above

Question 19

Which of the following proteins is observed exclusively in association with eukaryotic DNA replication?

A)single- strand binding proteins
B)DNA gyrase
C)telomerase
D)DNA polymerase I
E)DNA ligase

Question 20

Phosphorylation of is required for chromosome condensation.

A)topoisomerase II
B)DNA gyrase
C)cyclin
D)condensin
E)both A and B

Question 21

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

A)kinase inhibition pathway.
B)P450 - protease pathway.
C)ubiquitin- proteosome pathway.
D)cyclin proteolysis pathway.
E)none of the above

Question 22

The region of the centromere contains repeated DNA sequences known as .

Question 23

Cyclins modulate the progression of cells through the cell cycle by

A)directly activating G proteins.
B)increasing the production of DNA polymerases.
C)inducing synthesis of constitutively active forms of growth cell receptors.
D)activating protein kinases that are critical regulators of cell division.
E)degrading histones.

Question 24

During the G2 checkpoint in eukaryotic cells, the cell is assessed with regard to

A)chromosome attachment to the spindle.
B)DNA damage.
C)DNA replication.
D)presence of growth factors.
E)nutrients.

Question 25

DNA replication is

A)dispersive.
B)semi- conservative.
C)irregular.
D)conservative.
E)none of the above

Question 26

DNA repair in eukaryotes that facilitates replication in regions of thymine dimers is mediated by a unique DNA polymerase

A)6.
B)a.
C)a.
D)fi.
E)y.

Question 27

What is the ploidy of an organism that is 7n, where n = 5?

A)12
B)57
C)7
D)35
E)5

Question 28

The longest phase of the cell cycle is

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

Question 29

UV (ultraviolet)light- treated bacteria would most likely have DNA damage in the form of

A)pyrimidine dimer formation.
B)deamination.
C)intercalation of the bases.
D)analog incorporation.
E)direct transition of the bases.

Question 30

The protein(s)that facilitate the unfolding of chromatin fibers ahead of the replication fork is (are)

A)helicase.
B)replisomal proteins.
C)scaffold proteins.
D)chromatin remodeling proteins.
E)both A and B

Question 31

Which of the following would NOT inhibit a cell preparing to undergo mitosis?

A)chromosomal abnormalities
B)environmental signals that no new cells are needed
C)Chk1 inhibtion of Cdc25
D)p21 inhibition of G1
E)Cdc- activating kinase activity

Question 32

An isolate of a mutant bacterium appears to grow more slowly than the population (wild type)from which it was isolated. Further studies showed that the slower growth was due to a markedly reduced DNA polymerase I activity. From this information, one would expect that this organism would also be deficient in the activity of DNA

A)excision repair.
B)transcription.
C)recombination.
D)unwinding.
E)translation.

Question 33

In the cell cycle, a mitotic Cdk is present during

A)G2.
B)S.
C)G1.
D)M.
E)all of the above