Genetics Stuff Week 2

Question 0

What single nucleotide damage pathway repairs photodimers by the use of photolyase enzyme?

Answer 0

Photo-reversal of UV Lesions

Question 1

What single nucleotide damage pathway repairs normal nucleotides that can not base pair?

Answer 1

Mismatched Repair

Question 2

What single nucleotide damage pathway resects and replaces small lesions (modified bases) occurs in 3 steps:

• base is removed by DNA glycosylase
• phosphodiester backbone is broken and the deoxyribose sugar and phosphate are removed
• DNA polymerase beta and DNA ligase repair gap

Answer 2

Base Excision Repair (BER)

Question 3

What single nucleotide damage pathway repairs big helix distorting lesions by:

• cleavage of DNA fragment ~24 nucleotides on the 5’ side and ~5 nucleotides on the 3’ side of adduct
• filling in by polymerase delta or epsilon, PCNA and RPA

Answer 3

Nucleotide Excision Repair (NER) and interstrand Crosslink Repair

Question 4

What double strand break repair and interstrand crosslinks uses the homologous sequence a template

Answer 4

Homologous recombination

Question 5

What double strand break repair and interstrand crosslinks resects ends to uncover 2-3 nucleotide micro-homology

Answer 5

Non-homologous end joining

Question 6

What single nucleotide damage pathway fixes damage such as:

• base damage, non-bulky lesions, deamination, hydroxylation, oxidation,
• damage specific

Answer 6

Base Excision Repair (BER)

Question 7

What single nucleotide damage pathway repairs:

• bulky, helix distorting lesions, such as UV thymidine dimers, cisplatin adducts
• broad substrate specificity (any helix distortion)
• can be coupled to transcription - preferential repair of transcribed strand

Answer 7

Nucleotide excision repair (NER)