DNA Replication Practice Test

These questions are part of the practice quiz. Start practicing

• What best describes what happens at the replication fork?
• What is the role of SSB/RPA during replication?
• Which enzymes relieve positive supercoils ahead of the replication fork to allow replication to continue?
• Which prokaryotic DNA polymerase is primarily responsible for synthesizing both leading and lagging strands and has proofreading activity?
• What does the term supercoiling describe in DNA?
• Which are two key activities of the bacterial DNA polymerase III holoenzyme during replication?
• What is the role of PCNA ubiquitination and sumoylation in response to DNA damage during replication?
• Why is the lagging strand synthesized discontinuously, and what steps convert these fragments into a continuous strand?
• Cytosine deamination produces which base in DNA?
• Name a major DNA repair pathway that works with replication to maintain fidelity and briefly describe its function.
• Which enzyme removes RNA primers on the lagging strand in eukaryotes?
• Which statement about homologous recombination is true?
• Which enzyme seals the last nick on the lagging strand after primer removal in eukaryotes?
• What is required to give DNA Polymerase a starting 3' -OH end?
• Which step completes the repair after DNA synthesis and strand exchange in homologous recombination?
• In eukaryotes, what marks the nascent strand during mismatch repair?
• MutS in bacterial mismatch repair is responsible for what?
• In eukaryotic cells, which factors are required to license origins by loading the MCM2-7 helicase complex before firing?
• What is the function of the clamp at the replication fork?
• Mutations in DNA can cause what?
• Which direction do DNA polymerases synthesize new DNA strands?
• What is the function of replication protein A (RPA) in eukaryotic replication?
• Which statement about replication fork events in bacteria is correct?
• Which enzyme alleviates torsional strain ahead of the replication fork?
• What would happen if single-stranded DNA-binding proteins were absent during replication?
• RNA primers on the lagging strand are removed and the gaps are filled by which process?
• Define semi-conservative replication.
• Which sequence best describes the major steps of base excision repair?
• Which of the following is NOT a component of the CMG helicase complex in eukaryotes?
• Which model of DNA replication was disproved, proposing that one-half of the daughter DNA molecules should have both strands composed of newly polymerized nucleotides?
• Which enzyme is responsible for synthesizing RNA primers during DNA replication?
• MutL in bacterial mismatch repair is best described as?
• Which enzyme resolves interlinked daughter chromosomes (catenanes) after replication in bacteria?
• What is the purpose of the trombone model in lagging-strand synthesis?
• In Okazaki fragment processing, what is the specific role of FEN1 in relation to RNase H?
• What would be the consequences of a mutation in the proofreading exonuclease of DNA polymerase delta?
• What prevents re-licensing of origins after they have fired in the same cell cycle in eukaryotes?
• Which component acts as the sliding clamp to keep DNA polymerase attached during lagging-strand synthesis?
• Approximately how many replication events occur before telomere shortening leads to senescence?
• Which repair pathway is used for UV-induced pyrimidine dimers?
• Telomerase contains built-in RNA that serves as a primer complementary to telomeric repeats. Which sequence is its RNA template complementary to, as described?
• Which type of damage is BER best suited to repair?
• Which event occurs after strands are separated at the replication fork in bacteria?
• What are the typical lengths of Okazaki fragments in bacteria vs. eukaryotes?
• Depurination due to thermal energy results in what?
• What is the segment of a DNA molecule that is unwinding and undergoing replication?
• What is the function of primase in bacterial replication and what does it synthesize?
• Which enzyme unwinds the two DNA strands at the replication fork?
• What is the role of RNase H in primer removal during eukaryotic DNA replication?
• What are replication factories?
• Which single-stranded DNA-binding proteins are part of the replisome core components?
• In which direction does DNA polymerase move along the template strand?
• Which enzyme is not typically considered a core replication enzyme in bacteria?
• How do origins specification and licensing differ between yeast and bacteria?
• Which step is the initial processing in homologous recombination end processing?
• Senescence is best defined as which?
• In humans, which polymerase typically fills the single-nucleotide gap during BER?
• Which enzyme joins Okazaki fragments on the lagging strand?
• How does lagging-strand maturation differ between bacteria and eukaryotes?
• Which enzyme catalyzes the formation of the phosphodiester bond to seal the BER gap?
• In prokaryotes, which DNA polymerase is primarily responsible for synthesizing the leading and lagging strands?
• Telomerase may be reactivated in cancer cells to make them what?
• What unique ability of DNA gyrase allows bacterial DNA to maintain free negative supercoils?
• What happens when the wrong nucleotide is inserted into the new strand?
• If RNA primers are not removed properly during lagging-strand synthesis, what consequence would you expect?
• Which statement best describes the trombone model's role in coordinating leading and lagging-strand synthesis?
• BER primarily repairs what type of DNA damage?
• Which two major pathways repair double-strand breaks are used by eukaryotic cells?
• Depurination causes loss of which type of base?
• How do bacteria and eukaryotes achieve strand discrimination during mismatch repair?
• Where does DNA replication initiate?
• Which factors load the MCM2-7 helicase onto origins during G1 in eukaryotes?
• Provide an example of a chemical inhibitor of DNA replication and its effect.
• The mode of replication in which one new strand is synthesized continuously while the other is synthesized discontinuously is called?
• Which strand provides the template for ordering the sequence of nucleotides in an mRNA transcript?
• What is the Y-shaped region on a replicating DNA molecule where the parental strands are being unwound and new strands are synthesized?
• Okazaki fragments are produced on which strand during DNA replication?
• What is the strand that is synthesized in fragments called?
• Which enzyme ligates Okazaki fragments on the lagging strand?
• Which radiation types are ionizing and can cause DNA damage such as double-strand breaks?
• What stabilizes unwound DNA on the single-stranded regions?
• What is a major replication problem unique to eukaryotic linear chromosomes?
• UV radiation forms lesions that impair base pairing. What is the common name for these lesions?
• Which enzyme primes Okazaki fragments for lagging strand replication?
• What is the end replication problem and how do eukaryotes solve it?
• Which statement best describes the trombone model's role in coordinating leading and lagging-strand synthesis?
• What finishes the repair after flap removal in homologous recombination?
• Which eukaryotic DNA polymerases have 3' to 5' exonuclease proofreading during replication?
• What happens to RNA primers after DNA synthesis?
• Which enzymes fill and seal gaps after RNA primer removal on lagging strand?
• DNA Polymerase Beta participates in BER with which additional activity?
• Which method did Meselson-Stahl use to distinguish replication models?
• Which set of enzymes comprises the core DNA replication machinery?
• In prokaryotes, what is the origin of replication called?
• Which step in homologous recombination involves strand exchange and D-loop formation?
• Which enzyme seals the gaps between Okazaki fragments?
• What initiates bacterial DNA replication at oriC and which protein binds to oriC to start unwinding?
• In bacteria, which enzyme primarily removes RNA primers during lagging-strand synthesis?
• How is replication restarted after fork stalling in bacteria compared with eukaryotes?
• Depyrimidination is the loss of which base type?
• During mismatch repair, how is the strand that contains the error identified?
• What template does telomerase use to extend telomeres?
• How does telomerase activity affect the 3' end of linear chromosomes during replication?
• Which of the following is a source of DNA damage?
• After RNA primer removal, what fills the gaps with DNA on the lagging strand?
• What result supported the semi-conservative model of DNA replication in the Meselson-Stahl experiment?
• In bacteria, how is the parent strand identified during mismatch repair?
• Telomeres are repetitive DNA sequences at the ends of eukaryotic chromosomes. What is their described function?
• How many RNA primers are typically required on the leading strand versus the lagging strand per replication event?
• Why can't the primer of the last Okazaki fragment be replaced with DNA like other primers?
• What is the Ter/Tus system and its function in bacterial replication termination?
• Following base removal, which enzyme cleaves the DNA backbone at the resulting abasic site?
• Which factor is involved in restarting forks in bacteria?
• Which statement best explains why DNA strands are antiparallel?
• What is PCNA and what role does it play in replication?
• During replication stress, which checkpoint pathway is activated by RPA-coated ssDNA?
• Which statement about Okazaki fragment processing is true?
• What model did the Meselson-Stahl experiment support?
• What is the general cellular response when ATR and ATM checkpoints are activated during replication stress?
• In eukaryotes, which enzymes are responsible for primer removal on the lagging strand?
• What is the purpose of nucleotide base pairing in DNA?
• Which checkpoint kinase is activated by double-strand breaks?
• Which statement about the CMG complex components is correct?
• 3'-5' exonuclease activity of DNA polymerase serves what proofreading role?
• What enzyme synthesizes a short RNA primer to start DNA synthesis?
• Telomerase is an enzyme that lengthens telomeres. Which statement best describes its feature?
• Which polymerase fills in gaps after primer removal on the lagging strand in eukaryotes?
• Which enzyme synthesizes the leading strand in the 5' to 3' direction?
• Name the CMG helicase complex and its components in eukaryotes.
• During lagging strand synthesis, what marks the starting point for each fragment?
• Telomerase is what type of enzyme?
• Which enzyme seals the nick after the gap is filled in BER?
• Which mechanism distinguishes Type II topoisomerases during replication?
• Which term describes the model of DNA replication in which each daughter molecule contains one parental strand and one newly synthesized strand?
• What is the function of DNA ligase?
• Defects in base excision repair increase the risk of what?
• What is the role of topoisomerase at the replication fork?
• Which statement about the clamp loader and the sliding clamp is correct?
• Which activity removes the sugar-phosphate residue at the 5' end after abasic site incision in BER?
• Which statement about base excision repair is false?
• If MCM2-7 cannot load onto origins, what would be the consequence for replication?
• DNA repair is best described as which of the following?
• What is an RNA primer?
• What intermediate is produced when a damaged base is removed during BER?
• What is the strand that is synthesized continuously along the template strand in the 5' to 3' direction called?
• Which feature results from telomerase activity at chromosome ends?
• What is the role of the replisome, and which core components does it include?
• What is the approximate error rate of DNA polymerase per nucleotide added?
• Which enzyme removes RNA primers and replaces them with DNA in prokaryotes?
• Base Excision Repair is initiated by which enzyme that removes damaged bases?
• Thymine dimers are covalent links between adjacent thymine bases caused by UV exposure. They are an example of which type of lesion?
• What is the function of the beta sliding clamp in bacterial replication?
• What is the function of FEN1 in Okazaki fragment processing?
• In the CMG helicase complex, which component serves as the core helicase?
• Which enzyme introduces a double-stranded break ahead of the replication fork to relieve torsional stress?
• Which enzyme removes RNA primers on the lagging strand?
• Compare leading- and lagging-strand synthesis in terms of direction and continuity.
• Which enzyme unwinds the parental double helix at the start of DNA replication?
• Which enzyme relieves positive supercoiling ahead of the replication fork in bacteria?
• Which BER enzyme has both deoxyribose phosphate lyase activity and DNA polymerase activity?
• Why is DNA antiparallel?
• What is replication licensing, and which factors participate?
• Which protein promotes 3' end invasion into dsDNA to form a D-loop during homologous recombination?
• What is the result of DNA synthesis starting at the 3' end?
• Which direction does the proofreading exonuclease remove nucleotides?
• Which DNA repair pathway rejoins broken ends quickly without requiring a homologous template, often resulting in some sequence loss?
• DNA polymerases synthesize new strands in which direction relative to the new strand?
• Which type of damage is typically caused by gamma and X-ray ionizing radiation?
• What is the term for the particular sequence in the genome where DNA replication begins?
• Which kinases regulate origin firing during S phase in multicellular eukaryotes?
• What is the role of mismatch repair proteins?
• Which of the following is listed as a similarity between DNA and RNA?
• During initiation, which component loads the DnaB helicase onto DNA?
• Which enzyme synthesizes DNA by adding nucleotides to a growing DNA chain?
• In homologous recombination, which step processes broken ends to generate 3' overhangs?
• Which polymerases primarily synthesize the leading and lagging strands in human cells, respectively?
• Which enzyme seals nicks between Okazaki fragments on the lagging strand in bacteria?
• Okazaki fragments are formed on which strand during replication?
• What is the function of single-strand binding proteins during DNA replication?
• Which model suggested random interspersion of parental and new segments in daughter DNA molecules?