36 Questions
What is the purpose of nucleotide excision repair?
To correct thymine dimers induced by UV light
What is the name of the UV specific endonuclease that recognizes and cleaves the damaged strand?
uvrABC excinuclease
What is the purpose of mismatch repair?
To remove mis-incorporated bases during DNA replication
How many major proteins are involved in the MMR system in E. coli?
Three
Which protein in the MMR system recognizes the mismatch and recruits MutL?
MutS
What does MutH do in the MMR system?
Cuts the DNA strand flanking the mismatch
What does Exonuclease 1 do in the MMR system?
Chews all the nucleotides that were cut and removed flanking mismatch nucleotide by endonuclease
What does DNA polymerase III do in the MMR system?
Synthesizes and fills the gap
What is the purpose of Ligase in the MMR system?
Seals the gap
Which type of damage does nucleotide excision repair remove?
Thymine dimers induced by UV light
Which protein recruits MutH in the MMR system?
MutL
What happens after Ligase seals the gap in the MMR system?
The gap is synthesized and filled
What is the purpose of nucleotide excision repair?
To correct thymine dimers induced by UV light
What is the name of the UV specific endonuclease that recognizes and cleaves the damaged strand?
uvrABC excinuclease
What is the purpose of mismatch repair?
To remove mis-incorporated bases during DNA replication
How many major proteins are involved in the MMR system in E. coli?
Three
Which protein in the MMR system recognizes the mismatch and recruits MutL?
MutS
What does MutH do in the MMR system?
Cuts the DNA strand flanking the mismatch
What does Exonuclease 1 do in the MMR system?
Chews all the nucleotides that were cut and removed flanking mismatch nucleotide by endonuclease
What does DNA polymerase III do in the MMR system?
Synthesizes and fills the gap
What is the purpose of Ligase in the MMR system?
Seals the gap
Which type of damage does nucleotide excision repair remove?
Thymine dimers induced by UV light
Which protein recruits MutH in the MMR system?
MutL
What happens after Ligase seals the gap in the MMR system?
The gap is synthesized and filled
What is the purpose of nucleotide excision repair?
To remove thymine dimers induced by UV light
Which endonuclease is responsible for recognizing and cleaving the damaged strand during nucleotide excision repair?
uvrABC excinuclease
What is the purpose of mismatch repair?
To correct mis-incorporated bases during DNA replication
Which protein is responsible for recognizing the mismatch during MMR?
MutS
What is the role of MutL during MMR?
To cut the DNA strand flanking the mismatch
Which endonuclease cuts the DNA strand flanking the mismatch during MMR?
MutH
What is the role of Exonuclease 1 during MMR?
To chew all the nucleotides that were cut and removed flanking mismatch nucleotide by endonuclease
Which protein is responsible for synthesizing and filling the gap during MMR?
DNA polymerase III
What is the purpose of ligase during MMR?
To seal the gap
How many major proteins are involved in the MMR system in E. coli?
3
What is the name of the endonuclease responsible for recognizing and cleaving the damaged strand during nucleotide excision repair?
uvrABC excinuclease
Which repair system corrects mis-incorporated bases during DNA replication?
Mismatch repair
Study Notes
Nucleotide Excision Repair
- Purpose: to remove DNA damage, specifically bulky lesions and UV-induced damage
- Uses UV-specific endonuclease (UvrABC) to recognize and cleave the damaged strand
- Removes helix-distorting DNA lesions, including UV-induced cyclobutane pyrimidine dimers
Mismatch Repair
- Purpose: to correct mis-incorporated bases during DNA replication
- Involves 5 major proteins in E. coli: MutS, MutL, MutH, Exonuclease 1, and DNA polymerase III
- MutS recognizes the mismatch and recruits MutL
- MutH cuts the DNA strand flanking the mismatch
- Exonuclease 1 removes the mismatched DNA strand
- DNA polymerase III synthesizes and fills the gap
- Ligase seals the gap
- After Ligase seals the gap, the corrected DNA strand is restored
Test your knowledge on DNA repair mechanisms with this quiz! From nucleotide excision repair to mismatch repair, this quiz will challenge your understanding of how cells fix errors in DNA replication. Brush up on the key proteins and enzymes involved in these processes and discover new insights into the fascinating world of DNA repair. Perfect for biology students, researchers, and science enthusiasts.
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