When an error in DNA replication introduces a base-pair mismatch in a double-stranded DNA, the methyl-directed repair system O corrects the DNA strand that is methylated O corrects the mismatch by changing the template strand O corrects the mismatch by methylating uracil bases near the mismatch in the template strand O corrects the mismatch by methylating uracil bases near the mismatch in the newly replicated strand corrects the mismatch by changing the newly replicated strand

When an error in DNA replication introduces a base-pair mismatch in a double-stranded DNA, the methyl-directed repair system O corrects the DNA strand that is methylated O corrects the mismatch by changing the template strand O corrects the mismatch by methylating uracil bases near the mismatch in the template strand O corrects the mismatch by methylating uracil bases near the mismatch in the newly replicated strand corrects the mismatch by changing the newly replicated strand

Concepts of Biology

1st Edition

ISBN:9781938168116

Author:Samantha Fowler, Rebecca Roush, James Wise

Publisher:Samantha Fowler, Rebecca Roush, James Wise

Chapter9: Molecular Biology

Section: Chapter Questions

Problem 5RQ: The initial mechanism for repairing nucleotide errors in DNA is _____. a. mismatch repair b. DNA...

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If a mutation occurred that prevented single stranded binding proteins from binding, the result would be: O Replication would not be initiated O DNA would be synthesized on the leading strand, but not the lagging strand Replicating would be initiated, DNA would unwind, RNA primers would be laid down, but DNA polymerase would not bind O The newly synthesized RNA would not be able to leave the DNA template Replication would be initiated, but RNA primers would not anneal to the DNA
Match the bold DNA repair response(s) to the triggering type of DNA damage. Homologous Recombination Mishmatch Repair Base Excision Repair Nucleotide Excision Repair Non-homologous End Joining Single-strand DNA breaks Removal of repair lesions such as photoproducts caused by UV including Thymine dimers Double-Strand Break repair mechanism which is an accurate repair mechanism without any introduction of insertions or deletions. It requires a sister chromatid as a template. This repair mechanism uses just DNA glycosylase to remove Uracil (no other enzymes or complexes are required) then DNA polymerase can use the template stand to add the complementary base where the Uracil has been removedInterstrand Crosslink Repair This repair mechanism is used to recognize and repair mis-incorporation of base that can arise during DNA replication. Removal and replacement of modifying bases such as Uracil, 8-hyroxyguanine and others. Double-strand Break that is termed as “Quick and Dirty” as it is…
PolyADP-ribose polymerase (PARP) plays a keyrole in the repair of DNA single-strand breaks. In the pres-ence of the PARP inhibitor olaparib, single-strand breaksaccumulate. When a replication fork encounters a sin-gle-strand break, it converts it to a double-strand break,which in normal cells is then repaired by homologousrecombination. In cells defective for homologous recom-bination, however, inhibition of PARP triggers cell death.Patients who have only one functional copy of theBrca1 gene, which is required for homologous recombina-tion, are at much higher risk for cancer of the breast andovary. Cancers that arise in these tissues in these patientscan be treated successfully with olaparib. Explain how it isthat treatment with olaparib kills the cancer cells in thesepatients, but does not harm their normal cells.
List the steps in correct order of DNA mismatch repair in E. coli Group of answer choices Mut H; Mut L; Mut S; Mut H cleaves unmethylated nascent DNA strand MutH; MutS; Mut L; Mut H cleaves unmethylated nascent DNA strand MutL; MutH; MutS; Mut H cleaves unmethylated nascent DNA strand Mut S; Mut H; Mut L; Mut H cleaves unmethylated new DNA strand
Which of the following DNA repair mechanisms relies on homologous DNA recombination for the repair process? DNA proofreading O SOS response postreplication repair base excision repair mismatch repair
Which of the following is correct about the function of DNA Ligase? DNA ligase is used on the leading strand and it joins any disconnected strand together O DNA ligase is used on the lagging strand which helps in joining fragments of the strand together O DNA ligase is used on the lagging strand and it aids in correcting mistakes on this specific strand O DNA ligase is used to maintain the replication fork structure
Considening the structure of DNA, what kind of bonds hold one nucleotide to another within one side of the DNA molecule? O hydrogen O phosophodiester O lonic peptide
Which of the following enzymes can recognize and remove a damaged DNA base to leave an apurinic or apyrimidinic site? DNA ligase RecA AP endonuclease DNA polymerase DNA glycosylase
Which of the following mechanisms does not contribute to reducing the overall in vivo mutation rate found in most species? Mismatch repair of incorrectly inserted bases Replication-associated proteins, in addition to DNA polymerase, aid in fidelity of replication O Excision repair of thymine dimers O Tautomerization of nitrogenous bases Proofreading by DNA polymerase's 3' to 5' exonuclease activity
If a cell has trouble unwinding the DNA and relieving strain far ahead of the replication fork, in which of the following genes is there a mutation? Beve reverse transcriptase O gyrases/topoisomerases O single stranded binding proteins O ligase O helicase
DNA polymerase occasionally incorporates the wrong nucleotide during DNA replication. If left unrepaired, the base-pair mismatch that results will lead to mutation in the next replication. As part of a template strand, the incorporated wrong base will direct the incorporation of a base complementary to itself, so the bases on both strands of the DNA at that position will now be different from what they were before the mismatch event. The MER-minus strain of yeast does not have a functional mismatch excision repair system, but it has normal base excision repair and nucleotide excision repair systems. Which of the following statements is correct about differences in the mutation spectrum between MER-minus and wildtype yeast? More than one answer is correct. Options: More point mutations will arise in MER-minus yeast. Fewer point mutations will arise in MER-minus yeast as compared with wildtype. Of the total point mutations that…
The initial mechanism for repairing nucleotide errors in DNA is _____. a. mismatch repair b. DNA polymerase proofreading c. nucleotide excision repair d. thymine dimers