Genetics Mutation Repair

Question 1

Photoreactive repair is […] damaged. Photoreactive repair takes place in […], single-celled […], […], and some […] (not humans). The enzyme […] uses energy from visible light to break the bonds producing the photoproduct. Photolyase is encoded by the […] phr (photoreactive repair) gene

Answer 1

UV-induced; bacteria; eukaryotes; plants; animals; photolyase; E. coli

Question 2

Base excision repair (B E R) is a multistep process that may repair […] to a base or replace an incorrect base. […] recognize and remove modified bases, creating an AP site. AP […] creates a single-stranded “nick” near the AP site.

Answer 2

damage; DNA glycosylases; endonuclease

Question 3

Nick translation then occurs where […] initiate removal and replacement of nucleotides, including the AP site; DNA ligase seals the […].

Answer 3

DNA polymerases; sugar-phosphate backbone

Question 4

Nucleotide excision repair (N E R) is often used to repair U V-induced damage to D N A so is also known as […]

Answer 4

ultraviolet (UV) repair

Question 5

Mismatched nucleotides that escape DNA polymerase proofreading may be detected and repaired by […]

Answer 5

mismatch repair

Question 6

Repair enzymes distinguish between the original, correct nucleotide and the new, mismatched nucleotide using the presence of […] on the original strand

Answer 6

methylation

Question 7

The p53 repair pathway controls cell responses to mutation by deciding to: […]the cell cycle at the G1-to-S transition to allow time for repair; Direct the cell to undergo […]

Answer 7

Pause; programmed cell death