Deck 11: DNA Replication and Recombination

Question 1

The amount of DNA that is replicated from a single origin of replication is referred to as an_________ .

A)Okazaki fragment
B)ori
C)fork
D)primer
E)replicon

Answer 1

replicon

Question 2

Given the accompanying diagram,assume that a G1 chromosome left underwent one round of replication in ³H- thymidine and the metaphase chromosome right)had both chromatids labeled.Which of the following replicative models conservative,dispersive,semiconservative)could be eliminated by this observation?

A)semiconservative
B)dispersive
C)conservative
D)conservative and dispersive
E)semiconservative and dispersive

Answer 2

conservative

Question 3

Which DNA Polymerase III subunit is not part of the clamp loading assembly?

A)0
B)ç
C)6
D)v
E)y

Answer 3

A

Question 4

If E.coli DNA polymerase III was able to initiate DNA synthesis opposite a single- stranded template,which molecules)would no longer be essential?

A)single- stranded binding proteins
B)DNA gyrase
C)DNA ligase
D)DNA polymerase I
E)helicase

Question 5

DNA polymerase III adds nucleotides_________ .

A)in the place of the primer RNA after it is removed
B)to internal sites in the DNA template
C)to the 5' end of the RNA primer
D)to the 3' end of the RNA primer
E)to both ends of the RNA primer

Question 6

DNA replication occurs by adding_________ .

A)NTPs to the 5' end of the daughter strand
B)dNTPs to the 3' end of the template strand
C)NTPs to the 3' end of the daughter strand
D)dNTPs to the 3' end of the daughter strand
E)dNTPs to the 5' end of the template strand

Question 7

Which terms accurately reflect the nature of replication of the chromosome in E.coli?

A)bidirectional and multirepliconic
B)bidirectional and fixed point of initiation
C)unidirectional and fixed point of initiation
D)multirepliconic and telomeric
E)unidirectional and reciprocal

Question 8

As unwinding of the helix occurs during DNA replication,tension referred to as_________ is created ahead of the replication fork.This tension is relieved by the action of_________ .

A)supercoiling; single- stranded binding proteins
B)processivity; DNA gyrase
C)supercoiling; DNA gyrase
D)supercoiling; DNA helicase
E)processivity; primase

Question 9

Which of the following terms accurately describes the replication of DNA in vivo?

A)conservative
B)dispersive
C)nonreciprocal
D)semidiscontinuous
E)nonlinear

Question 10

DNA polymerase I is thought to add nucleotides_________ .

A)to the 5' end of the primer
B)on single- stranded templates without need for an RNA primer
C)to the 3' end of the primer
D)in the place of the primer RNA after it is removed
E)in a 5' to 5' direction

Question 11

Which of the following statement about DNA replication in E.coli is correct?

A)Single- stranded binding proteins are only required on the leading strand.
B)Only the lagging strand needs to be primed.
C)There are two molecules of DNA polymerase III per replication fork.
D)DNA polymerase I follows closely behind DNA helicase in the replication fork.
E)There are two molecules of DNA helicase per replication fork.

Question 12

The discontinuous aspect of replication of DNA in vivo is caused by_________.

A)topoisomerases cutting the DNA in a random fashion
B)sister- chromatid exchanges
C)trinucleotide repeats
D)the 5' to 3' polarity restriction
E)polymerase slippage

Question 13

The protein product of the E.coli dnaE gene is a component of_________ .

A)DNA helicase
B)DNA ligase
C)primase
D)DNA polymerase III
E)DNA polymerase I

Question 14

DNA replication proceeds_________ .

A)discontinuously
B)progressively
C)semiconservatively
D)dispersively
E)unidirectionally

Question 15

If DNA replication were fully conservative,how many intact parental double helices would have been detected in Meselson and Stahl's experiment after three rounds of replication?

A)1
B)7
C)8
D)0
E)3

Question 16

The protein responsible for the initial step in unwinding the DNA helix during replication of the bacterial chromosome is coded for by the_________ gene.

A)polB
B)dnaA
C)gyrA
D)polA
E)dnaE

Question 17

During DNA replication,_________are 1000- 2000 nucleotide long strands synthesized on the _________ strand to maintain the_________ of replication.

A)Okazaki fragments; leading,accuracy
B)primers,lagging; continuity
C)Okazaki fragments; lagging; bidirectionality
D)primers; leading; discontinuity
E)Okazaki fragments; leading; semidiscontinuity

Question 18

After ONE round of DNA replication in Meselson and Stahl's classic experiment,_________.

A)the conservative model was conclusively proven to be an inaccurate model
B)both the conservative and the semiconservative models were still possibilities
C)the semiconservative model was conclusively proven to be the accurate model
D)the dispersive model was conclusively proven to be an inaccurate model
E)all three models of replication were still possibilities

Question 19

Which cluster of terms accurately reflects the nature of DNA replication in prokaryotes?

A)fixed point of initiation,bidirectional,conservative
B)random point of initiation,bidirectional,semiconservative
C)random point of initiation,unidirectional,semiconservative
D)fixed point of initiation,bidirectional,semiconservative
E)fixed point of initiation,unidirectional,conservative

Question 20

Which of the following statements about the oriC region in E.coli is incorrect?

A)It includes five repeating sequences of 9 base pairs.
B)It is 245 base pairs in length.
C)It includes three repeating sequences of 13 base pairs.
D)It is rich in AT base pairs.
E)It is directly recognized and bound by DNA helicase.

Question 21

Compare and contrast DNA Polymerases I,II,and III in E.coli.What capabilities are shared,and which are exclusive to only one type of polymerase?

Question 22

Telomerase reads _________ as a template and synthesizes _________as a product.

A)DNA; RNA
B)DNA; DNA
C)DNA; protein
D)RNA; RNA
E)RNA; DNA

Question 23

The process of making DNA from an RNA template is referred to as_________ .

A)transcription
B)transversion
C)recombination
D)reverse transcription
E)translation

Question 24

Explain why DNA primers can be used in in vitro DNA synthesis reactions,but not in vivo.

Question 25

The activity of_________ would be quickly undone in the absence of single- stranded binding protein.

A)DNA ligase
B)DNA polymerase I
C)primase
D)DNA polymerase III
E)DNA helicase

Question 26

DNA replication in eukaryotes_________ .

A)occurs without the need of a primer
B)takes place multiple times per cell cycle
C)synthesizes DNA approximately 25 times faster than in prokaryotes
D)utilizes a single type of DNA polymerase
E)initiates at multiple origins

Question 27

Describe the benefit to researchers of conditional mutants.

Question 28

The Meselson and Stahl's experiment provided conclusive evidence for the semiconservative replication of DNA in E.coli.What pattern of bands would occur in a CsCl gradient for conservative replication?

Question 29

A molecule that possesses both a protein component and an RNA component is referred to as a _________.

A)holoenzyme
B)ribonucleoprotein
C)polymerase
D)tetramer
E)dimer

Question 30

Why does DNA replication have to be semidiscontinuous in order to be bidirectional?

Question 31

Which eukaryotic DNA polymerase would least likely be involved in repair?

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

Question 32

Which of the following is not an essential step in homologous recombination?

A)exonuclease degradation
B)strand displacement
C)duplex separation
D)branch migration
E)endonuclease nicking

Question 33

Chromatin is defined as_________ .

A)DNA complexed with protein
B)supercoiled loops of bacterial DNA
C)hybrid molecules of DNA and RNA
D)a catalytic molecule with a protein component and an RNA component
E)genetic material found only in mitochondria

Question 34

Structures located at the ends of eukaryotic chromosomes are called_________ .

A)permissive mutations
B)recessive mutations
C)telomeres
D)centromeres
E)telomerases

Question 35

Briefly describe what is meant by the term autoradiography and identify a classic experiment that used autoradiography to determine the replicative nature of DNA in eukaryotes.

Question 36

A drug is added to a culture of E.coli cells that inhibit DNA gyrase.Predict the effect of this drug on DNA replication in the affected cells.

Question 37

Explain the need for,and action of,DNA gyrase in bacterial DNA replication.

Question 38

Assembly of new nucleosomes is carried out by complexes abbreviated_________ .

A)DSB
B)TLS
C)TERC
D)SSB
E)CAF

Question 39

Telomerase adds nucleotides to the_________ .

A)5' end of the daughter strand
B)5' end of the parental strand
C)3' end of the parental strand
D)3' end of the daughter strand

Question 40

DNA replication in vivo requires a primer with a free 3' end.What molecular species provides this 3' end,and how is it provided?

Question 41

What is meant by homologous recombination?

Question 42

Describe two processes for which recombination is essential.

Question 43

Describe a somewhat extraordinary finding related to the Tetrahymena telomerase enzyme.

Question 44

What is the name of the replication unit in prokaryotes,and how does it differ in eukaryotes?

Question 45

Compare and contrast DNA replication in prokaryotes and eukaryotes.

Question 46

Compare the rate of DNA replication in prokaryotes and eukaryotes.

Question 47

Why are bacteria not dependent on telomerase for complete DNA replication?

Question 48

What is meant by processivity of a DNA- synthesizing enzyme?

Question 49

What is meant by a gene knockout?

Question 50

Describe the DNA base sequence arrangement at the end of the Tetrahymena chromosome and the resolution of DNA replication at the end of a linear DNA strand.