Nucleotide excision repair is also used to fix some types of damage caused by UV radiation, for instance, when you get a sunburn.
UV radiation can make cytosine and thymine bases react with neighboring bases that are also Cs or Ts, forming bonds that distort the double helix and cause errors in DNA replication
.
What does nucleotide excision repair do?
Nucleotide excision repair is a mechanism in which
a damaged region of DNA is cut out and replaced by DNA synthesized using the undamaged strand as template
.
What type of repair to DNA happens during replication?
DNA polymerase proofreading: Proofreading by DNA polymerase corrects errors during replication. Some errors are not corrected during replication, but are instead corrected after replication is completed; this type of repair is known as
mismatch repair
.
How does nucleotide excision repair differ from other repair mechanisms?
The main difference between base excision repair and nucleotide excision repair is that the base excision repair pathway corrects only the damaged bases, which are non-bulky lesions, whereas the nucleotide excision repair pathway corrects bulky DNA adducts through the removal of a short-single stranded DNA segment …
How does nucleotide excision repair differ from base excision repair quizlet?
Nucleotide-excision repair reverses the chemical reaction that caused the lesion, whereas base-excision repair removes the damaged bases and replaces them with normal ones
.
What statement best describes what happens during nucleotide excision repair of damaged DNA?
What happens during nucleotide excision repair of damaged DNA?
Enzymes unwind the DNA, cut out a section on one stand that contains the DNA damage, and resynthesize the section with the correct DNA sequence
.
How does nucleotide excision repair differ from base excision repair Mcq?
Excision repair: Damage to one or a few bases of DNA is often fixed by removal (excision) and replacement of the damaged region.
In base excision repair, just the damaged base is removed. In nucleotide excision repair, as in the mismatch repair we saw above, a patch of nucleotides is removed
.
What happens if nucleotide excision repair fails?
Base excision repair is responsible for fixing damaged DNA bases due to cellular metabolism, resulting from reactive oxygen species, methylation, deamination, hydroxylation, and SSBs [77]. Failure to repair these types of lesions can result in
point mutations
(Fig. 2).
What prevents the wrong nucleotide from being added to the new strand during DNA replication?
During proofreading,
DNA polymerase enzymes
recognize this and replace the incorrectly inserted nucleotide so that replication can continue. Proofreading fixes about 99% of these types of errors, but that’s still not good enough for normal cell functioning.
What is replication repair?
Post replication repair is
a mechanism specialized in tolerating lesions in single stranded template
. DNA replication is a multistep process with two key events; (1) unwinding of the annealed double helix to expose ssDNA and (2) using this ssDNA as template to synthesize daughter strands.
How does DNA replication repair itself?
How is DNA replicated? Replication occurs in three major steps:
the opening of the double helix and separation of the DNA strands, the priming of the template strand, and the assembly of the new DNA segment
. During separation, the two strands of the DNA double helix uncoil at a specific location called the origin.
How does DNA mismatch repair work?
Mismatches are commonly due to tautomerization of bases during DNA replication. The damage is repaired
by recognition of the deformity caused by the mismatch, determining the template and non-template strand, and excising the wrongly incorporated base and replacing it with the correct nucleotide
.
Which enzyme involved in the mechanism of nucleotide excision to repair DNA has endonuclease activity?
The process of nucleotide excision repair is controlled in Escherichia coli by the
UvrABC endonuclease enzyme complex
, which consists of four Uvr proteins: UvrA, UvrB, UvrC, and DNA helicase II (sometimes also known as UvrD in this complex).
Which two you we are component molecules can the DNA during nucleotide excision repair?
Which two Uvr component molecules scan the DNA during nucleotide excision repair? Explanation: In nucleotide excision repair complex of two
UvrA and UvrB
molecules scan the DNA with two UvrA subunits being responsible for detecting the distortions to the helix.
Which statement is true with respect to mismatch repair and nucleotide excision repair NER )?
Which statement is true with respect to mismatch repair and nucleotide excision repair (NER)?
Mismatch repair fixes thymine dimers caused by exposure to UV light, while NER fixes errors in DNA replication
. Mismatch repair follows the same steps as NER.
What is the correct definition of nucleotide excision repair quizlet?
nucleotide excision repair
replaces several damaged nucleotides plus additional nucleotides and uses the DNA on the opposite strand as a template to fill in the gap
.
Which of the following DNA repair mechanisms is used to repair DNA damage done by formation of thymine dimers?
UV-induced thymine dimers can be repaired by
photoreactivation
, in which energy from visible light is used to split the bonds forming the cyclobutane ring.
What is excision repair mechanism?
The basic mechanism of excision repair involves: (1) damage recognition; (2) subunit assembly; (3) dual incisions that result in excision of the damage-containing oligomer; (4) resynthesis to fill in the gap; and (5) ligation to regenerate an intact molecule.
Which of the following enzyme works in the nucleotide excision repair?
Which of the following enzyme works in the nucleotide excision repair? Explanation:
ABC excinuclease
involves the removal of short, usually 12 nucleotide segment. This system is best studied in E. coli.
What mechanisms can repair DNA?
At least five major DNA repair pathways—
base excision repair (BER), nucleotide excision repair (NER), mismatch repair (MMR), homologous recombination (HR) and non-homologous end joining (NHEJ)
—are active throughout different stages of the cell cycle, allowing the cells to repair the DNA damage.
Which chemical mutagen affects DNA replication?
Explanation:
Base analog
is mutagenic only for replicating DNA while acridine dye, alkylating, and deaminating agents are mutagenic to both replicating and non-replicating DNA.
