Molecular Bio (Exam 1): DNA Repair

In __________ repair, one strand of DNA is excised and replaced with resynthesis, using the complementary strand as a template.

excision.

In __________ repair, nucleotides are removed from newly synthesized strands.

mismatch.

Plants have a convenient mechanism to repair __________, because they are frequently exposed to UV in sunlight.

double-strand breaks (DSBs).

__________ damages are often restricted to a single base and can disappear after replication, and therefore does not affect DNA replication or transcription.

Nondistorting.

Nondistorting damages (do/do not) affect DNA replication or transcription.

do not.

Base mismatch persists only until the next __________.

replication.

The time window to repair __________ is crucial, because it will persist throughout replication.

base mismatch.

Distorting (structural) damages create physical obstacles that __________ cannot pass, and cells can die.

polymerase (DNA/RNA).

Pyrimidine dimers are examples of __________ damages created by UV.

distorting.

Distorting damage remains after __________ unless repaired.

DNA replication.

Error-prone polymerases synthesize only a __________ stretch of DNA.

short.

In NER, damage is recognized by an __________ that cleaves DNA on both sides of the damage (incision).

endonuclease.

In NER, incision involves __________ DNA on both sides of damage.

cleaving.

In NER, excision involves __________ of damaged DNA region inbetween nicks.

removal.

In NER, a 5’-3’ __________ removes the stretch of damaged strand, including extra nucleotides that were not damaged.

exonuclease.

In NER, excision and synthesis occur __________.

simultaneously.

In E. coli NER, the Uvr system makes __________ on both sides of damaged DNA.

incisions.

What complex makes incisions on both sides of damaged DNA in E. coli NER?

UvrB/UvrC complex.

Why is the Uvr NER system named Uvr?

It repairs radiation damage from UV.

What makes excisions to remove the DNA region with damage in NER in E. coli?

UvrD helicase and DNA pol I.

RNA polymerase stalls when it encounters structural damage on:

the template strand.

Xeroderma pigmentosum is a human disease caused by mutations in what genes?

NER.

In eukaryotes, what protein recognizes damages anywhere in the genome?

XPC.

In eukaryotes, what is the sensor for global genome repair NER?

XPC.

In eukaryotes, what is the sensor for transcription-coupled repair?

RNA pol II.

Global genome repair recognizes damage anywhere in the what?

genome.

Transcriptionally active genes are preferentially repaired via what?

transcription-coupled repair.

Global genome repair and transcription-coupled repair differ in their mechanisms of damage _______.

recognition.