DNA Replication, Repair, and Recombination
50 questions available
Questions
What is the approximate mutation rate observed in bacteria like E. coli when corrected for silent mutations and normalized per nucleotide copied?
View answer and explanationIn eukaryotes, what is the approximate length of Okazaki fragments found on the lagging strand during DNA replication?
View answer and explanationWhat is the primary function of single-strand DNA-binding (SSB) proteins during DNA replication?
View answer and explanationWhat is the combined accuracy of DNA replication after all three steps of proofreading (polymerization, exonucleolytic proofreading, and mismatch repair) are completed?
View answer and explanationHow does the strand-directed mismatch repair system in E. coli distinguish the newly synthesized DNA strand from the old template strand?
View answer and explanationWhat is the role of DNA topoisomerase I in relieving the 'winding problem' during DNA replication?
View answer and explanationApproximately how many origins of replication are used each time a human cell divides?
View answer and explanationWhat is the function of the enzyme telomerase?
View answer and explanationWhat is the most frequent type of spontaneous DNA damage that occurs in human cells, happening about 18,000 times per cell per day?
View answer and explanationWhich DNA repair pathway is primarily responsible for removing bulky lesions, such as those caused by sunlight or large hydrocarbons?
View answer and explanationWhat is a key difference in the initiation of replication between bacteria and eukaryotes regarding the helicase?
View answer and explanationWhat is the primary mechanism used by translesion polymerases to replicate through damaged DNA?
View answer and explanationWhich of the following is the 'quick and dirty' solution for repairing double-strand breaks and is predominant in mammalian somatic cells?
View answer and explanationWhat is the key role of the RecA/Rad51 protein in homologous recombination?
View answer and explanationWhat is a Holliday junction?
View answer and explanationWhat is the primary mechanism by which DNA-only transposons move in the cut-and-paste transposition pathway?
View answer and explanationWhat type of enzyme is central to the life cycle of a retrovirus like HIV, responsible for converting its RNA genome into DNA?
View answer and explanationWhat is the approximate rate of movement of a eukaryotic replication fork?
View answer and explanationHow many subunits compose the eukaryotic CMG helicase?
View answer and explanationWhat is the consequence of a mutation in the human Brca1 or Brca2 genes?
View answer and explanationIn the process of base excision repair, what is the role of the enzyme AP endonuclease?
View answer and explanationIn homologous recombination during meiosis, what specialized protein complex is responsible for creating the initial programmed double-strand break?
View answer and explanationWhat is the typical length of the RNA primers synthesized by DNA primase in eukaryotic cells?
View answer and explanationHow many times per second does the DNA in an isolated nucleosome unwrap from each end?
View answer and explanationWhat is the consequence of 'gene conversion' during meiotic recombination?
View answer and explanationWhich class of transposable elements predominates in bacteria and is largely responsible for the spread of antibiotic resistance?
View answer and explanationWhat is the key structural feature of the protein-DNA filament formed by RecA/Rad51 that facilitates strand invasion?
View answer and explanationWhat is the main reason that DNA replication in eukaryotes is confined to the S phase of the cell cycle?
View answer and explanationHow many histone proteins are found in the core of a single nucleosome?
View answer and explanationWhat happens to the parental H3-H4 tetramers and H2A-H2B dimers when a replication fork passes through a nucleosome?
View answer and explanationWhat is the primary consequence for a cell if the ATM protein is defective, as seen in the disease ataxia telangiectasia (AT)?
View answer and explanationIn the mechanism for nonretroviral retrotransposition, what serves as the primer for the reverse transcription step?
View answer and explanationWhat is the typical size range of the human telomeric repeat sequence GGGTTA?
View answer and explanationWhat is the 'end-replication problem' that eukaryotes solve using telomeres and telomerase?
View answer and explanationIn the process of repairing a stalled replication fork via 'fork reversal', what acts as the template for the DNA synthesis that bypasses the damage?
View answer and explanationWhat is the role of the clamp loader in DNA replication?
View answer and explanationWhat type of chemical reaction does a DNA glycosylase catalyze in base excision repair?
View answer and explanationHow much of the human genome is estimated to be composed of recognizable relics of past transposition events?
View answer and explanationWhich type of mobile genetic element is responsible for generating I elements in Drosophila and L1 elements in humans?
View answer and explanationWhat is the primary distinguishing feature of conservative site-specific recombination compared to transposition?
View answer and explanationBy the age of 70, a typical human somatic cell is estimated to contain more than how many 'scars' from inaccurate repair by nonhomologous end joining?
View answer and explanationWhat is the function of the Ku protein in nonhomologous end joining?
View answer and explanationDuring which cell-cycle phases is homologous recombination predominantly used to repair double-strand breaks?
View answer and explanationWhat is the function of the enzyme DNA gyrase in bacteria?
View answer and explanationWhy is an erasable RNA primer thought to be advantageous for DNA replication compared to a DNA primer?
View answer and explanationWhat is the typical total length of Okazaki fragments synthesized by Pol-delta in eukaryotes?
View answer and explanationThe accidental deamination of 5-methylcytosine in vertebrate DNA produces which natural nucleotide?
View answer and explanationAccording to the text, how do RNA-only viruses like SARS-CoV-2 achieve proofreading during the replication of their RNA genomes?
View answer and explanationWhat is the primary role of the protein shelterin?
View answer and explanationWhat triggers the termination of DNA replication in eukaryotes?
View answer and explanation