DAPZOI
Home Ask MCQ Quiz Topics Login


DNA Replication MCQ Questions & Answers

DNA Replication MCQs : This section focuses on the "DNA Replication". These Multiple Choice Questions (MCQs) should be practiced to improve the DNA Replication skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.




Question 1

Proofreading activity to maintain the fidelity of DNA synthesis

A. occurs after the synthesis has been completed
B. is a function of the 3'-5' exonuclease activity of the DNA polymerases
C. requires the presence of an enzyme separate from the DNA polymerases
D. occurs in prokaryotes but not eukaryotes

View Answer

Question 2

The enzyme that catalyzes the synthesis of DNA is called

A. DNA polymerase
B. DNA gyrase
C. DNA ligase
D. helicase

View Answer

Question 3

Which isotopes were used by the researchers who first confirmed the semiconservative nature of DNA replication?

A. Nitrogen
B. Carbon
C. Oxygen
D. Sulfur

View Answer

Question 4

Which of the following enzymes unwind short stretches of DNA helix immediately ahead of a replication fork?

A. DNA polymerases
B. Helicases
C. Single-stranded binding proteins
D. Topoisomerases

View Answer

Question 5

During which of the following process a new copy of a DNA molecule is precisely synthesized?

A. Trasformation
B. Transcription
C. Translation
D. Replication

View Answer

Question 6

How many numbers of replicon is found in E.coli?

A. Five replicon
B. Two replicon
C. Single replicon
D. Multiple replicon

View Answer

Question 7

Which enzyme used to join bits of DNA?

A. DNA polymerase
B. DNA ligase
C. Endonuclease
D. Primase

View Answer

Question 8

The replication of chromosomes by eukaryotes occurs in a relatively short period of time because

A. the eukaryotes have more amount of DNA for replication
B. the eukaryotic replication machinery is 1000 times faster than the prokaryotes
C. each chromosome contains multiple replicons
D. eukaryotic DNA is always single stranded

View Answer

Question 9

When was DNA polymerase III discovered as the major enzyme behind DNA replication in bacteria?

A. 1949
B. 1959
C. 1969
D. 1989

View Answer

Question 10

How many types of replication models were considered before the semiconservative nature of DNA replication was confirmed?

A. 1
B. 2
C. 3
D. 4

View Answer

Question 11

Which of the following would relax negatively supercoiled DNA?

A. DNA gyrase
B. Type I topoisomerase
C. Collagen
D. Elastin

View Answer

Question 12

Name the protein, which is used for termination of replication?

A. DnaC
B. SSB
C. Tus protein
D. DNA polymerase

View Answer

Question 13

Temperature-sensitive mutants can not replicate their chromosomes at non-permissive temperatures.

A. True
B. False

View Answer

Question 14

Base sequence of each parental strand considered to synthesis new complementary strand.

A. True
B. False

View Answer

Question 15

DNA unwinding is done by ____________

A. Ligase
B. Helicase
C. Topoisomerase
D. Hexonuclease

View Answer

Question 16

Which of the following enzymes is the principal replication enzyme in E. coli?

A. DNA polymerase I
B. DNA polymerase II
C. DNA polymerase III
D. None of the mentioned

View Answer

Question 17

DNA gyrase is inhibited by

A. tetracycline
B. nalidixic acid
C. both (a) and (b)
D. cephalosporin

View Answer

Question 18

During DNA replication in prokaryotes, synthesis begins on the circular chromosome

A. always at the same place
B. at any stretch of DNA that is high in AT pairs
C. randomly on the chromosome
D. at the promoter

View Answer

Question 19

In E.coli, which enzyme synthesizes the RNA primer for Okazaki fragments?

A. DnaA
B. DnaC
C. DnaG
D. All of the above

View Answer

Question 20

DNA replication rates in prokaryotes are approximately of the order of

A. 10 bases per second
B. 1,00 bases per second
C. 1,000 bases per second
D. 10,000 bases per second

View Answer

Question 21

Which of the following possesses both 5'-3' and 3'-5' exonuclease activity?

A. Kornberg enzyme
B. DNA polymerase III
C. Taq DNA polymerase
D. None of these

View Answer

Question 22

What is the origin of replication?

A. Particular site at which DNA replication starts
B. Site which prevents initiation
C. Random location on the DNA
D. Site at which replication terminated

View Answer

Question 23

What is a mode of replication in E.coli?

A. Intermediate
B. Dispersive
C. Conservative
D. Semiconservative

View Answer

Question 24

Double-helix structure of DNA is discovered by___________

A. Gobind Khurana
B. Nirenberg
C. Watson and Crick
D. Darwin

View Answer

Question 25

Both strands of DNA serve as templates concurrently in

A. replication
B. excision repair
C. mismatch repair
D. none of the above

View Answer

Question 26

What is the reaction in DNA replication catalyzed by DNA ligase?

A. Addition of new nucleotides to the leading strand
B. Addition of new nucleotide to the lagging strand
C. Formation of a phosphodiester bond between the 3’-OH of one Okazaki fragment and the 5’-phosphate of the next on the lagging strand
D. Base pairing of the template and the newly formed DNA strand

View Answer

Question 27

Which of the following enzymes remove supercoiling in replicating DNA ahead of the replication fork?

A. DNA polymerases
B. Helicases
C. Primases
D. Topoisomerases

View Answer

Question 28

Which of the following is true about DNA polymerase?

A. It can synthesize DNA in the 5’ to 3’ direction
B. It can synthesize DNA in the 3’ to 5’ direction
C. It can synthesize mRNA in the 3’ to 5’ direction
D. It can synthesize mRNA in the 5’ to 3’ direction

View Answer

Question 29

Which of the following repairs nicked DNA by forming a phosphodiester bond between adjacent nucleotides?

A. Helicase
B. DNA gyrase
C. Topoisomerases
D. DNA ligase

View Answer

Question 30

Which enzyme removes the positive supercoils generated when the replication fork?

A. helicase
B. endonuclease
C. exonuclease
D. gyrase

View Answer

Question 31

Which enzyme joins the Okazaki fragments into a continuous strand?

A. gyrase
B. topoisomerase
C. ligase
D. helicase

View Answer

Question 32

Which of the following enzyme is responsible for initiating DNA replication?

A. polymerase
B. ligase
C. primase
D. gyrase

View Answer

Question 33

The lagging strand is synthesized discontinuously.

A. True
B. False

View Answer

Question 34

DNA gyrase is inhibited by

A. tetracycline
B. nalidixic acid
C. Both A and B
D. cephalosporin

View Answer

Question 35

Movement of the replication fork generates ________________ in the unreplicated portion of DNA.

A. positive supercoils
B. negative supercoils
C. untranslated regions
D. amino acid substitutions

View Answer

Question 36

What is DNA replication?

A. Conservative
B. Non-conservative
C. Semi-conservative
D. None of the mentioned

View Answer

Question 37

The synthesis of DNA by DNA polymerase occurs in the

A. 3' to 5' direction
B. 5' to 5' direction
C. 5' to 3' direction
D. 3' to 3' direction

View Answer

Question 38

How many copies (approximately) of DNA polymerase III are present in a typical bacterial cell?

A. 10
B. 50
C. 100
D. 200

View Answer

Question 39

Which of the following protein does not involve in the initiation of replication?

A. DnaA
B. SSB (Single strand binding protein)
C. DnaB
D. DnaF

View Answer

Question 40

In E.coli, which enzyme synthesizes the RNA primer for Okazaki fragments?

A. DnaA
B. DnaC
C. DnaG
D. all of these

View Answer

Question 41

Which of the following statements on replication in E.coli is correct?

A. It occurs in a unidirectional manner
B. It occurs in bidirectional manner
C. Always uses T7 DNA polymerase when infected by T7 phage
D. Occurs only when λ phase has infected E. coli

View Answer

Question 42

Semi-conservative DNA replication was first demonstrated in ____________

A. Drosophila melanogaster
B. Escherichia coli
C. Streptococcus pneumonae
D. Drosophila melanogaster

View Answer

Question 43

Both strands of DNA serve as templates concurrently in

A. replication
B. excision repair
C. mismatch repair
D. none of these

View Answer

Question 44

Eukaryotes differ from prokaryote in mechanism of DNA replication due to ____________

A. Use of DNA primer rather than RNA primer
B. Different enzyme for synthesis of lagging and leading strand
C. Discontinuous rather than semi-discontinuous replication
D. Unidirectional rather than semi-discontinuous replication

View Answer

Question 45

Name the protein, which is responsible for the formation of RNA primer?

A. Topoisomerase
B. Gyrase
C. Helicase
D. Primase

View Answer

Question 46

Which of the following protein is required for connecting Okazaki fragments?

A. Scaffold protein
B. Helicase
C. Primase
D. DNA gyrase

View Answer

Question 47

Who made the discovery that one DNA strand is synthesized discontinuously in fragments?

A. Francis Crick
B. Reiji Okazaki
C. James Watson
D. Louis Pasteur

View Answer

Question 48

Which of the following lacks 3'-5' exonuclease activity?

A. Short fragment of DNA polymerase I
B. Taq DNA polymerase
C. T4 DNA ligase
D. All of the above

View Answer