- Which enzyme is primarily responsible for unwinding the DNA during replication?
a) DNA ligase
b) Helicase
c) DNA polymerase
d) Topoisomerase
Answer: b) Helicase - What is the function of DNA polymerase during replication?
a) Unwinding the DNA
b) Synthesizing RNA primers
c) Adding nucleotides to the growing DNA strand
d) Joining Okazaki fragments
Answer: c) Adding nucleotides to the growing DNA strand - Which enzyme synthesizes the RNA primer required for DNA replication?
a) DNA polymerase III
b) Primase
c) Ligase
d) Helicase
Answer: b) Primase - Which enzyme is responsible for removing the RNA primers after DNA replication?
a) DNA polymerase I
b) DNA polymerase III
c) Ligase
d) Primase
Answer: a) DNA polymerase I - What is the role of topoisomerase in DNA replication?
a) Unwinds the DNA
b) Synthesizes RNA primers
c) Relieves supercoiling tension ahead of the replication fork
d) Joins Okazaki fragments
Answer: c) Relieves supercoiling tension ahead of the replication fork - What direction does DNA replication occur?
a) 3′ to 5′
b) 5′ to 3′
c) 2′ to 5′
d) Both directions
Answer: b) 5′ to 3′ - What is formed on the lagging strand during DNA replication?
a) Continuous strand
b) Okazaki fragments
c) RNA primers
d) Telomeres
Answer: b) Okazaki fragments - What enzyme seals the gaps between the Okazaki fragments?
a) DNA ligase
b) DNA polymerase
c) Helicase
d) Primase
Answer: a) DNA ligase - Which strand of DNA is synthesized continuously during replication?
a) Leading strand
b) Lagging strand
c) Both strands
d) None of the strands
Answer: a) Leading strand - Which enzyme adds nucleotides to the growing DNA strand?
a) DNA polymerase III
b) DNA polymerase I
c) Helicase
d) Ligase
Answer: a) DNA polymerase III - What is the role of single-strand binding proteins (SSBPs) during DNA replication?
a) They help in the synthesis of the RNA primer
b) They prevent the reannealing of the separated DNA strands
c) They relieve the supercoiling tension
d) They facilitate the addition of nucleotides
Answer: b) They prevent the reannealing of the separated DNA strands - What is the main difference between the leading and lagging strands in DNA replication?
a) Leading strand is synthesized in one piece, while lagging strand is in fragments
b) Leading strand is synthesized in fragments, while lagging strand is in one piece
c) Leading strand requires RNA primers, while lagging strand does not
d) Lagging strand is synthesized by RNA polymerase
Answer: a) Leading strand is synthesized in one piece, while lagging strand is in fragments - What is the replication fork?
a) The site where DNA is synthesized
b) The point where the DNA strand separates into two strands
c) The enzyme that adds nucleotides to the growing strand
d) The site of DNA proofreading
Answer: b) The point where the DNA strand separates into two strands - Which enzyme is responsible for proofreading the newly synthesized DNA strand?
a) DNA polymerase III
b) DNA polymerase I
c) Ligase
d) Topoisomerase
Answer: a) DNA polymerase III - In which direction does DNA polymerase synthesize the new DNA strand?
a) 5′ to 3′
b) 3′ to 5′
c) 2′ to 3′
d) 1′ to 3′
Answer: a) 5′ to 3′ - Which component is required for the formation of Okazaki fragments?
a) RNA primer
b) DNA ligase
c) DNA polymerase I
d) Telomerase
Answer: a) RNA primer - Which of the following helps in the relaxation of supercoiled DNA during replication?
a) DNA polymerase III
b) Topoisomerase
c) Helicase
d) DNA ligase
Answer: b) Topoisomerase - What is the final product of DNA replication?
a) Two double-stranded DNA molecules
b) One double-stranded DNA molecule
c) One single-stranded DNA molecule
d) Two single-stranded DNA molecules
Answer: a) Two double-stranded DNA molecules - Which of the following is NOT involved in DNA replication?
a) Helicase
b) Ligase
c) ATP
d) Ribosomes
Answer: d) Ribosomes - What happens to the RNA primers after DNA replication?
a) They remain on the DNA strand
b) They are replaced by DNA nucleotides
c) They are removed by helicase
d) They become part of the Okazaki fragments
Answer: b) They are replaced by DNA nucleotides - Which enzyme is responsible for elongating the DNA strand by adding nucleotides?
a) RNA polymerase
b) DNA polymerase I
c) DNA polymerase III
d) DNA ligase
Answer: c) DNA polymerase III - What is the role of primase in DNA replication?
a) Synthesizes the RNA primer
b) Seals the gaps between the DNA strands
c) Unwinds the DNA
d) Adds new nucleotides to the growing strand
Answer: a) Synthesizes the RNA primer - How many replication forks are formed during DNA replication?
a) One
b) Two
c) Multiple
d) None
Answer: b) Two - Which of the following proteins binds to the single-stranded DNA to prevent reannealing during replication?
a) Ligase
b) Topoisomerase
c) Single-strand binding proteins (SSBPs)
d) Primase
Answer: c) Single-strand binding proteins (SSBPs) - What is the function of DNA ligase in DNA replication?
a) Unwinds the DNA
b) Joins the Okazaki fragments
c) Synthesizes RNA primers
d) Proofreads the DNA strand
Answer: b) Joins the Okazaki fragments - Which enzyme helps to resolve the topological strain created by the unwinding of DNA?
a) DNA polymerase I
b) Topoisomerase
c) Ligase
d) Helicase
Answer: b) Topoisomerase - What is the role of the sliding clamp in DNA replication?
a) It stabilizes the DNA polymerase on the DNA strand
b) It helps unwind the DNA
c) It adds nucleotides to the DNA strand
d) It removes RNA primers
Answer: a) It stabilizes the DNA polymerase on the DNA strand - Which of the following enzymes is responsible for the synthesis of the new DNA strand in both the leading and lagging strands?
a) DNA polymerase III
b) DNA polymerase I
c) DNA ligase
d) Helicase
Answer: a) DNA polymerase III - What structure is formed when two replication forks meet during DNA replication?
a) Replication bubble
b) Telomere
c) Okazaki fragment
d) Nucleosome
Answer: a) Replication bubble - Which of the following is a major challenge for the lagging strand during DNA replication?
a) Synthesis in the 3′ to 5′ direction
b) Continuous replication
c) Formation of Okazaki fragments
d) Removal of RNA primers
Answer: c) Formation of Okazaki fragments
These questions provide a comprehensive understanding of DNA replication, the mechanisms, and enzymes involved in the process.
