1
Q
Base misincorporation (e.g. from tautomerization)
A
- Proofreading
- DNA polymerases with 3’ –> 5’ exonuclease activity
2
Q
Single-strand DNA nicks (radiation; spontaneous hydrolysis)
A
- Direct Repair
- DNA ligase
3
Q
- UV photoproducts: cyclobutane pyrimidine dimers; 6-4 photoproducts
A
- Direct repair
- DNA photolyase [but not in humans :-( ]
4
Q
O^6 alkylguanine products
A
- Direct repair
- MGMT (methylguanine methyltransferase)
5
Q
- Abnormal bases in DNA (mostly dU)
- covalently modified bases (alkylation products)
- spontaneous deamination (C –> U; 5-methyl-C –> T)
A
- Base Excision Repair
- DNA glycosidases, Apurinic (AP) endonuclease, DNA Pol 1, DNA ligase
6
Q
UV photoproducts and other lesions that cause significant structural changes (e.g. bulky covalent adducts)
A
- Nucleotide Excision Repair
- ABC exinuclease, DNA polymerase I, DNA ligase
7
Q
- Base mismatches; Short deletions and insertions; Base modifications that distort double helix
A
- DNA Mismatch Repair
- methylases: MutH, MutL, MutS; exonuclease I; DNA polymerase I or III; DNA ligase
8
Q
- Loss of template continuity (mostly X-ray induced double-strand breaks and certain kinds of replication errors)
A
- Recombinational Repair
- not covered in this course
9
Q
DNA Pol 1 has two exonuclease activities
A
- 3’-5’ exonuclease proofreads for accuracy
- 5’-3’ exonuclease chews through primers
10
Q
chemical mutagens
A
DNA intercalating agents cause indels
11
Q
Backward slippage
A
insertion
12
Q
Forward slippage
A
deletion
13
Q
Huntington’s Disease
A
expansion of triplet repeats
14
Q
gain-of-function mutations
A
protooncogenes, dominant
15
Q
loss-of-functions mutations
A
antioncogenes (tumor suppressors), recessive
16
Q
DNA damage
A
17
Q
A
BIOC 406
flashcards
Decks in class (8)
# Cards
