DNA damage And Repair Flashcards
What gene protects against single strand breaks and when mutated can result in persistent double strand breaks?
BRCA
What is the most genotoxic type of DNA damage?.
Double strand breaks
What’s replication stress?
Inefficient replication that causes the replication fork to stall slow or break.
List the three methods of DNA damage in replication.
Replication machinery defective
Replication stress
Defective response and repair mechanisms
Which direction does DNA polymerase add nucleotides?
DNA GROWS 5’ to 3’
what are the sections of DNA ON THE LAGGING STRAND CALLED BEFORE THEY JOIN UP?
Okazaki fragments
What enzyme joins Okazaki fragments
DNA Ligase
What is the structural difference between RNA nucletides and DNA nucleotides
The 2’ carbon in RNA HAS AN -OH and in DNA it has a -H
What makes insertions and deletions more likely?
Base sequence repeats
Which strand loops out resulting in deletions?
Template
If the new strand loops out you get an?
Insertion
What is the repair mechanism for a base mismatch?
Exonculease part of the DNA polymerase
Why is a double band break bad?
Disrupts molecular continuity Difficult to resolve Can lead to mutations Cell death may result Translocation more likely Diseases associated DNA replication stress
What disease is linked to triple base repeats?
Huntingdons CAG repeat 35-121 more repeats means younger onset
What does the protein from the mutant gene in Huntingdons?
Disrupts normal function with of basal ganglia high coordinate motor action
