DNA polymerase I is important in the coordination of leading and lagging strand synthesis
Answer
True
False
Question 3
Question
You receive a nasty sunburn. Your DNA initially attempts to repair this damage through [blank_start]Nucleotide Excision Repair[blank_end].This initial attempt is unsuccessful but the DNA replication blockage is bypassed by [blank_start]Translesion Synthesis[blank_end].
[blank_start]End-joining repair[blank_end] fixes double stranded breaks and it is an [blank_start]inaccurate[blank_end] repair system.
Answer
End-joining repair
Mismatch repair
inaccurate
accurate
Question 9
Question
Origins of replication are usually [blank_start]AT-rich[blank_end] because they are joined by only 2 hydrogen bonds (compared to 3 for [blank_start]G-C pairs[blank_end]) so it requires [blank_start]less[blank_end] energy to separate the DNA strands for replication to begin.
Answer
AT-rich
GC-rich
AU-rich
G-C pairs
A-T pairs
A-U pairs
less
more
Question 10
Question
[blank_start]Single strand binding protein[blank_end] binds to unwound DNA during replication to prevent the formation of secondary structure or hairpins (or hold the unwound DNA in a rigid, unpaired structure).
What are some differences between base excision repair and mismatch repair.
Answer
Repair different types of base mismatches: replication errors for MR and modified bases eg by deamination for BER
Mismatches are detected differently - MR distinguishes between the parental and newly synthesised strand shortly after DNA replication and corrects the new strand; BER recognises particular incorrect pairs, e.g. those that have arisen by common deamination events and corrects the base that has been deaminated (eg C to U or methylC to T)
MR acts straight after replication while BER acts at any time.
First step involves removal of base only in BER but involves cutting the DNA backbone in MR, or could express this as glycosylase involved (to remove base) in BER but not MR (if you just mentioned the removal of a base, you needed to specify this was in the first step as both processes involve loss of backbone and repair)
Stretch of backbone removed in MR but only 1 nucleotide in BER
The backbone is removed by exonuclease in MR but an endonuclease in BER (like point 4 in similarities, you needed to be fairly specific here.
The backbone is removed by endonuclease in MR but an exonuclease in BER (like point 4 in similarities, you needed to be fairly specific here.