Deck 11: DNA Replication

Question 1

You have isolated what appears to be alien DNA. While studying its replication, you performed the exact experiment Meselson and Stahl did. After three generations, the DNA is subjected to a CsCl gradient and only one band appears. What type of replication does this DNA undergo?

A)Semiconservative
B)Conservative
C)Dispersive

Answer 1

C

Question 2

Which of the following best describes the mechanism of DNA replication in which both parental strands remain together following replication?

A)Dispersive
B)Semi-conservative
C)Conservative
D)All of the answers are correct

Answer 2

C

Question 3

Bacterial DNA has how many origins of replication?

A)0
B)1
C)10
D)Depends on the size of the DNA

Answer 3

B

Question 4

You have discovered a strain of

A) $\alpha$
B) $\beta$
C) $\varepsilon$
D) $\sigma$
E)coli that grows very slowly-the generation time is nearly 12 hours compared to the normal 20-30 minutes.Upon further investigation, you find a mutation in the DNA polymerase III gene.What subunit of the holoenzyme does this mutation affect the most?

Question 5

Attaches adjacent Okazaki fragments, forming a continuous DNA strand.

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

Question 6

Okazaki fragments do which of the following?

A)Assist in forming the replication fork
B)Bind to the oriC region
C)Assist in the synthesis of DNA from the lagging strand
D)Reform the double-helix following replication
E)None of the answers are correct

Question 7

Which of the following best describes the double-helix of DNA?

A)It has directionality
B)The strands are arranged in an anti-parallel arrangement
C)The strands are complementary
D)All of the answers are correct

Question 8

DNA polymerases add new nucleotides in what direction?

A)5' to 3'
B)3 ' to 5'
C)Both directions

Question 9

The purpose of DNA replication is to produce ______.

A)Two daughter strands
B)Two parental strands
C)Two template strands
D)None of the answers are correct

Question 10

How many DNA polymerases are found in prokaryotes?

A)5
B)7
C)9
D)12

Question 11

DNA helicase enzymes move in what direction along the DNA during DNA replication?

A)5' to 3'
B)3' to 5'
C)They remain stationary

Question 12

Which of the following best describes the mechanism of DNA replication in which both a parental strand and daughter strand are combined following replication?

A)Dispersive
B)Semi-conservative
C)Conservative
D)All of the answers are correct

Question 13

Responsible for the majority of DNA replication.

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

Question 14

DNA polymerase III has the ability to begin synthesis of the new daughter strands immediately following the formation of the replication fork.

Question 15

Manufactures a 10-12 base segment of RNA.

A)DNA ligase
B)Primase
C)Topoisomerase
D)DNA polymerase I
E)DNA polymerase III

Question 16

The first generation of replication in the Meselson and Stahl experiment disproved which theory of replication?

A)Semiconservative
B)Conservative
C)Dispersive
D)None-it took more than one generation to disprove the theory

Question 17

Synthesizes the lagging strand of the DNA.

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

Question 18

Which of the following is not correct concerning the initiation of bacterial replication?

A)It involves a region of the DNA called oriC
B)DNA proteins bind to the DNA to begin separation of the strands
C)The strands are initially separated at GC-rich regions of DNA
D)Following initial separation, DNA helicase enzymes continue to unwrap the DNA

Question 19

Prevents supercoiling ahead of the replication fork.

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

Question 20

Fills in small regions of DNA where the RNA primers were located.

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

Question 21

GGGCCATTCGAACGTCCGAAAATGCCCCTGAATGAAAATTTTGGCCC. The primer used for replication in vitro is CCCGGTAAGCTT. Where is the 5' end for the template and primer, respectively?

A)Left, left
B)Right, left
C)Left, right
D)Right, right

Question 22

Lesion-replicating polymerases are _________.

A)Only active in skin cells
B)Used to replicate damaged DNA
C)Used to induce genetic diversity
D)None of the answers are correct

Question 23

Which of the following is NOT a reason for the high fidelity of the newly synthesized DNA molecule?

A) The hydrogen bonding between purines and pyrimidines is stable.
B) The DNA polymerase is unlikely to form bonds between nucleotides if they are mismatched.
C) The DNA polymerase has exonuclease functions.
D) The DNA polymerase has the ability to change the structure of the base in order to form the correct bond.

Question 24

Replication usually begins in GC rich regions due to the presence of only 2 hydrogen bonds between the bases.

Question 25

DNA polymerase III is the main replication enzyme in prokaryotes. What is it in eukaryotes?

A)DNA pol a
B)DNA pol d
C)DNA pol b
D)DNA pol g

Question 26

What functions are accomplished by the primosome?

A)Tracking along DNA
B)Tracking along DNA, separating double stranded DNA
C)Tracking along DNA, separating double stranded DNA, synthesizing RNA primers
D)Tracking along DNA, separating double stranded DNA, synthesizing RNA primers, adding nucleotides

Question 27

Which of the following is a restriction placed on DNA polymerase?

A) DNA polymerase can attach new nucleotides only in the 5' to 3' direction.
B) DNA polymerases must begin synthesis using an RNA primer.
C) DNA polymerases must have a template strand to copy from.
D) All of these are restrictions of DNA polymerase.

Question 28

DNA polymerase is a primer-dependent enzyme that functions only in the 5'-3' direction. These are the two most fundamental concepts to understanding this enzyme. Based on this, which of the following enzyme pairs are analogous in prokaryotes and eukaryotes?

A)DNA pol I : DNA pol $\alpha$
B)DNA pol II : DNA pol $\beta$
C)DNA pol III : DNA pol $\sigma$
D)All of the answers are correct

Question 29

What was the control in Arthur Kornberg's in vitro replication experiment described in this chapter?

A) The use of radiolabeled nucleotide triphosphates
B) The exclusion of template DNA in one test tube
C) Adding perchloric acid
D) The use of
E)coli proteins

Question 30

What types of mutants were essential to the discovery of new replication enzymes?

A)Gain-of-function mutations
B)Lethal mutations
C)Temperature-sensitive mutations
D)None of the answers are correct

Question 31

DNA polymerases are unable to bind to what areas of the chromosome?

A) Centromeres
B) 3' end of telomeres
C) Origins of replication

Question 32

The movement of the replication fork in bacterial replication is unidirectional.

Question 33

Which of the following stops the replication of DNA in prokaryotes?

A)Tus proteins
B)DNA ligase
C)Okazaki fragments
D)The end of the chromosome

Question 34

The proofreading of the DNA occurs in the _________.

A)5' to 3' direction
B)3' to 5' direction
C)Both directions

Question 35

You extract DNA from an

A)The methylated strand
B)The strand that is not methylated
C)Neither-they are the same "age."
E)coli cell and observe it is hemi-methylated.Which strand of DNA is older?

Question 36

The origin of replication in bacteria is called OriC.

Question 37

The Meselson-Stahl experiments used ³⁵S radioisotopes to determine the mechanism of DNA replication.

Question 38

The Meselson-Stahl experiments supported the model of dispersive DNA replication.

Question 39

Which of the following is an example of a processive enzyme?

A)DNA polymerase I
B)DNA polymerase III
C)DNA ligase
D)Okazaki fragments

Question 40

In eukaryotes, which of the following is similar to the oriC region of prokaryotes?

A)Dam
B)ARS elements
C)Promoters
D)Telomeres

Question 41

After the action of the helicase, single-stranded binding proteins keep the parental DNA strands from reforming a double-helix.

Question 42

DNA polymerase III has an error in replication once every 100 million nucleotides.

Question 43

The problem in synthesizing the 3' end of chromosomes is solved by the use of the telomerase enzyme.

Question 44

Catenanes can only form in cells with circular chromosomes, such as bacteria.

Question 45

The ability of the DNA polymerase to remove mismatched bases is called exonuclease cleavage (proofreading).

Question 46

The synthesis of the daughter strand of DNA occurs away from the replication fork in the leading strand.

Question 47

DNA polymerase III can synthesize a new strand of DNA at the rate of 300 nucleotides per minute.

Question 48

A primosome consists of a polymerase and a single-stranded binding protein.