PCB 2061 Chapter 1 PDF

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In the uvr excision repair system of E. coli, long patch repair replaces _______ nucleotides, and a short patch repair replaces ______ nucleotides? 1500-9000; 12

In the uvr excision repair system in E. coli, which enzyme unwinds damaged DNA? UvrD

What is the enzyme in bacteria that directly photoreactivates pyrimidine dimers? Photolyase phr

Which statement is TRUE in regard to eukaryotic transcription-linked nucleotide excision repair NER? The large subunit of RNA polymerase is degraded; TFIIH remains and recruits XP proteins to repair DNA damage.

In the uvr excision repair system in E. coli, which enzyme routinely synthesizes DNA to replace the excised strand? DNA polymerase I

In the uvr excision repair system in E. coli, which enzyme recruits uvrC? UvrB

Which type of DNA damage does NOT result in stopped replication or stopped transcription? Mismatch; deamination

What step is NOT part of excision repair?

Dam methylation

In eukaryotic BER, long patch repair replaces _______ nucleotides, and a short patch repair replaces ______ nucleotides? 2-10; 1

In base excision repair, the uracil glycosylase enzyme corrects DNA damage by biased replacement of ________ to ______? U-G; C-G

Which of the following is NOT the activity of Mfd protein? It degrades RNA polymerase

What protein is uniquely linked to transcription and DNA repair in eukaryotes? TFIIH helicases XPB and XPD

What protein is uniquely linked to transcription and DNA repair in E. coli? Mfd

Which statement is FALSE in regard to eukaryotic base excision repair BER? In BER, polymerase delta and epsilon replaces long stretch of nucleotides, which is 1500-9000 bases. *correct answer is replace 2-10 bases aka long patch repair

In the uvr excision repair system in E. coli, which steps DO NOT require hydrolysis of ATP?

UvrA recognition of damaged nucleotide

What statement is FALSE? The uvr-/recA- double mutants can tolerate up to 50 thymine dimers. *They can only tolerate 2

What statement is FALSE? Msh2/Msh3 complex binds DNA loops resulting from replication slippage. Msh2/Msh6 complex binds single base mismatches, while other proteins do the repairing. Roles of MutS and MutL are completely different between bacterial and MSH eukaryotic proteins. MSH repair system in yeast is homologous to the E. coli MutS/L system. Roles of MutS and MutL are completely different between bacterial and MSH eukaryotic proteins.

When two bases are mismatched, how does the cell know which base to repair? Dam methylation system marks the GATC sequence in the original strand and unmethylated daughter strand is repaired.

Which step is NOT a part of the SOS repair? RecA cuts LexA thus inhibiting the inhibitors activity

What activity is encoded by MutY and what does it do? Adenosine glycosylase; creates apurinic site

In dam methylation mismatch repair, which protein acts as the nuclease and nicks the unmethylated strand? MutH

Which induction conditions do NOT trigger the SOS response? Mismatch mutations

Which statement is FALSE in regard to recombination repair of the replication errors? A replication fork may stall when it encounters a mismatch.

Mutations in genes that encode __________ represent the Mutator phenotype. proteins that participate in recombination and chiasmata formation w/ proteins that direct transcription w/ proteins responsible of ligating DNA w repair system proteins, or fidelity of replication proteins

Which gene is NOT an example of a Mutator gene? FEN1 endonuclease...