Non-homologous end joining — Flashcards

Flashcard 1: Chronic exposure to Arsenic may cause cancer by metabolites (ex. Dimethyl-Arsenic) inhibiting _____ motifs in Base-Excision Repair and Nucleotide-Excision Repair enzymes

Answer: zinc finger

Flashcard 2: Which enzyme catalyzes the formation of a phosphodiester bond between Okazaki fragments?_____

Answer: DNA ligase

Flashcard 3: Which base excision repair enzyme is responsible for removing nucleotides at the 3' end?_____

Answer: Lyase

Flashcard 4: When using CRISPR/Cas9 that introduce a double strand break to knock-out target DNA, _____ repair the gap introduced by this Cas9 variant

Answer: nonhomologous end joining enzymes

Flashcard 5: What form of DNA repair fixes mutations induced by UV radiation?_____

Answer: nucleotide excision repair

Flashcard 6: What form of DNA repair fixes mutations due to DNA replication errors?_____

Answer: mismatch repair

Flashcard 7: What are the four mechanisms of DNA repair?

Answer: Nuceotide excision repair Base excision repair Mismatch repair Nonhomologous end joining

Flashcard 8: non-homologous end joining

Answer: join 2 dsDNA ends

Extra: double-stranded breaks (when no homologous chromosome is around to use as a guide)ataxia telangiectasia

Flashcard 9: mismatch repair

Answer: 1. new strand recognized (lacks methylation) 2. mismatched nucleotides removed 3. DNA pol/ligase fills/seals gap

Extra: Mismatched bases on newly synthesized DNA strandhereditary nonpolyposis colorectal cancer (HNPCC)

Flashcard 10: base excision repair (BER)

Answer: 1. specific glycosylases recognize and remove damaged bases 2. AP endonuclease removes AP DNA 3. DNA pol/ligase fill/seal gap

Extra: spontaneous/toxic changes to the base itself; most often deamination