DNA repair — Flashcards

Flashcard 1: What are the four mechanisms of DNA repair?

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

Flashcard 2: 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 3: 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 4: 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

Flashcard 5: nucleotide excision repair (NER)

Answer: 1. endonuclease removes short ssDNA segment containing lesion 2. DNA pol/ligase fill/seal gap

Extra: bulky adducts, commonly thymine dimers caused by UV radiation xeroderma pigmentosa

Flashcard 6: Is homologous recombination error prone? _____

Answer: No

Extra:  Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=6] https://onlinemeded.org?ref=anki 

Flashcard 7: BRCA1 and BRCA2 are tumor suppresors that are involved in mediating the _____ pathway of DNA repair

Answer: Homologous Recombination

Extra:  Watch Pancreatic Cancer & Islet Cell Tumors [https://dashboard.sketchy.com/study/medical/courses/medical-pathophysiology/units/medical-pathophysiology-neuro/videos/medical-pathophysiology-neuro-intracranial-hypertension-and-tumors-adult-cns-tumors?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical]Watch associated Bootcamp video [https://app.bootcamp.com/med-school/pathology/videos/cellular-injury-and-neoplasia?index=10] https://onlinemeded.org?ref=anki 

Flashcard 8: Chronic exposure to Aflatoxins may cause cancer by causing a(n) G:C --> T:A transversion in codon 249 of the _____ gene

Answer: TP53

Extra:  https://onlinemeded.org/spa/immunology?ref=anki 

Flashcard 9: Aplastic anemia may be caused by Fanconi anemia, which occurs due to a(n) _____ defect, resulting in bone marrow failure

Answer: dsDNA repair

Extra:   Watch associated Bootcamp video [https://app.bootcamp.com/med-school/hematology-and-oncology/videos/normocytic-anemia?index=10] https://onlinemeded.org?ref=anki Atlas: Other: 

Flashcard 10: What process is used by mismatch repair enzymes to distinguish between old and new DNA strands in prokaryotes? _____

Answer: DNA methylation

Extra:  https://onlinemeded.org?ref=anki 

Flashcard 11: Mechanisms to repair _____ breaks are defective in Ataxia telangiectasia, Fanconi anemia, and SCID

Answer: dsDNA

Extra:   Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=4] https://onlinemeded.org/spa/immunology?ref=anki 

Flashcard 12: Nonhomologous End Joining (NHEJ) occurs _____ S phase of the cell cycle

Answer: before

Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=6] https://onlinemeded.org?ref=anki 

Flashcard 13: Is Nonhomologous End Joining error prone? _____

Answer: Yes

Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=6] https://onlinemeded.org?ref=anki 

Flashcard 14: DNA polymerase pauses and checks ("proof-reads") via _____ activity

Answer: 3' -> 5' exonuclease

Extra:  Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-replication-transcription-and-translation?index=2] https://onlinemeded.org?ref=anki 

Flashcard 15: Which base excision repair enzymes are responsible for filling and sealing the gap from the excised bases? _____ (filling) and _____ (sealing)

Answer: DNA polymerase-β

Extra:  Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=3] https://onlinemeded.org?ref=anki 

Flashcard 16: What form of DNA repair fixes mutations due to spontaneous/toxic deamination? _____

Answer: Base excision repair

Extra:  Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=3] https://onlinemeded.org?ref=anki 

Flashcard 17: _____ results from lack of excision endonuclease activity to remove pyrimidine dimers

Answer: Xeroderma pigmentosum

Extra:   https://onlinemeded.org?ref=anki 

Flashcard 18: If DNA repair is not possible, p53 induces _____

Answer: apoptosis

Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/hematology-and-oncology/videos/principles-of-oncology-and-therapeutics?index=10] https://onlinemeded.org/spa/inflammation-and-neoplasia/apoptosis/acquire?ref=anki 

Flashcard 19: In Homologous Recombination, dsDNA breaks are recognized by the ATM protein and the FA Core Complex, which activate _____ to recruit enzymes to repair the break

Answer: BRCA1/2

Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=6] https://onlinemeded.org?ref=anki 

Flashcard 20: Which base excision repair enzyme is responsible for removing nucleotides at the 5' end? _____

Answer: AP-endonuclease

Extra:  Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=3] https://onlinemeded.org?ref=anki 

Flashcard 21: MUTYH-associated polyposis is a(n) _____ syndrome with multiple colorectal adenomas and an increased risk of colorectal cancer

Answer: autosomal recessive

Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/gastroenterology/videos/colorectal-pathology?index=10] https://onlinemeded.org?ref=anki 

Flashcard 22: Recognition and facilitation of excision of mismatched nucleotides occur via enzymes found on two genes: _____ or _____

Answer: MSH2 (MutS)

Extra:  Watch Colorectal Polyps & Cancer [https://dashboard.sketchy.com/study/medical/courses/medical-pathophysiology/units/medical-pathophysiology-gi/videos/medical-pathophysiology-gi-colorectal-and-anal-disorders-colorectal-polyps-and-cancer?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical]Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=3] https://onlinemeded.org/spa/gastroenterology/colon-cancer/acquire?ref=anki 

Flashcard 23: The enzymes that repair pyrimidine dimer mutations are _____ and _____

Answer: DNA polymerase

Extra:  Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=3] https://onlinemeded.org?ref=anki 

Flashcard 24: In base excision repair, base-specific _____ remove the altered base and create a(n) AP (apurinic/apyrimidinic) site

Answer: glycosylases

Extra:  Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=3] https://onlinemeded.org?ref=anki 

Flashcard 25: What form of DNA repair fixes mutations induced by UV radiation? _____

Answer: Nucleotide excision repair

Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=3] https://onlinemeded.org?ref=anki 

Flashcard 26: The enzyme that recognizes and excises pyrimidine dimer mutations is _____

Answer: excision endonuclease

Extra:  Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=3] https://onlinemeded.org?ref=anki 

Flashcard 27: Homologous Recombination occurs _____ S phase of the cell cycle, using a(n) sister chromatid as a template

Answer: after

Extra: Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=6] https://onlinemeded.org?ref=anki 

Flashcard 28: What form of DNA repair fixes mutations due to DNA replication errors? _____

Answer: Mismatch repair

Extra:  Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=3] https://onlinemeded.org?ref=anki 

Flashcard 29: Nonhomologous End Joining is defective in _____ and Ataxia Telangiectasia

Answer: SCID

Extra:  Watch Combined B & T Cell Disorders [https://dashboard.sketchy.com/study/medical/courses/medical-pathophysiology/units/medical-pathophysiology-immunology/videos/medical-pathophysiology-immunology-immunodeficiency-combined-b-and-t-cell-disorders?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical]Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=6] https://onlinemeded.org/spa/pediatrics/immunodeficiency/acquire?ref=anki 

Flashcard 30: The _____ is involved in regulating Homologous Recombination, and when mutated causes Bloom syndrome

Answer: BLM helicase

Extra:   Watch DNA Replication [https://dashboard.sketchy.com/study/medical/courses/medical-biochemistry/units/medical-biochemistry-molecular-biology/videos/medical-biochemistry-molecular-biology-dna-dna-replication?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical] https://onlinemeded.org?ref=anki 

Flashcard 31: Xeroderma Pigmentosum is inherited in a(n) _____ fashion

Answer: autosomal recessive

Extra:  Watch Autosomal Recessive Diseases [https://dashboard.sketchy.com/study/medical/courses/medical-pharmacology/units/medical-pharmacology-antimicrobials/videos/medical-pharmacology-antimicrobials-cell-wall-and-membrane-active-antibiotics-monobactams-and-carbapenems?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical] Watch Actinic Keratosis, Squamous Cell Carcinoma & Basal Cell Carcinoma [https://dashboard.sketchy.com/study/medical/courses/medical-pathophysiology/units/medical-pathophysiology-musculoskeletal-derm/videos/medical-pathophysiology-musculoskeletal-and-derm-derm-actinic-keratosis-squamous-cell-carcinoma-and-basal-cell-carcinoma?utm_source=anki&utm_medium=partnership&utm_campaign=february_update&utm_content=medical]Watch associated Bootcamp video [https://app.bootcamp.com/med-school/genetics/videos/dna-mutations-damage-and-repair?index=4] https://onlinemeded.org?ref=anki 

Flashcard 32: What phase of the cell cycle do base excision repairs occur?_____

Answer: Throughout the cell cycle

Flashcard 33: What form of DNA repair fixes mutations induced by UV radiation?_____

Answer: nucleotide excision repair

Flashcard 34: Which base excision repair enzyme is responsible for removing nucleotides at the 5' end?_____

Answer: AP-endonuclease

Flashcard 35: What form of DNA repair fixes mutations due to spontaneous/toxic deamination?_____

Answer: Base excision repair

Flashcard 36: The _____ is involved in regulating Homologous Recombination, and when mutated causes Bloom syndrome

Answer: BLM helicase

Flashcard 37: What phase of the cell cycle do nucleotide excision repairs occur?_____

Answer: G1

Flashcard 38: Is Nonhomologous End Joining error prone?_____

Answer: Yes

Flashcard 39: The enzyme that recognizes and excises pyrimidine dimer mutations is _____

Answer: excision endonuclease

Flashcard 40: 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 41: What enzyme catalyzes the conversion of UDP to dUDP?_____

Answer: Ribonucleotide reductase

Flashcard 42: What process is used by mismatch repair enzymes to distinguish between old and new DNA strands in prokaryotes?_____

Answer: DNA methylation

Flashcard 43: Patients with Xeroderma Pigmentosum cannot repair _____ formed as a result of UV-B exposure

Answer: Thymidine Dimers

Flashcard 44: Deamination of 5-methyl cytosine forms _____

Answer: thymine

Flashcard 45: _____ results from lack of excision endonuclease activity to remove pyrimidine dimers

Answer: Xeroderma pigmentosum

Flashcard 46: What mutation is induced by UV radiation?_____

Answer: Pyrimidine dimers (e.g. thymine dimers)

Flashcard 47: Xeroderma Pigmentosum is an inherited pathology due to a defective _____ pathway

Answer: Nucleotide Excision Repair

Flashcard 48: When using CRISPR/Cas9 to knock-in DNA, a _____ must be added to guide insertion of a construct

Answer: repair template

Flashcard 49: DNA polymerase pauses and checks ("proof-reads") via _____ activity

Answer: 3' -> 5' exonuclease

Flashcard 50: Which enzyme catalyzes the formation of a phosphodiester bond between Okazaki fragments?_____

Answer: DNA ligase

Flashcard 51: Nonhomologous End Joining (NHEJ) occurs _____ S phase of the cell cycle

Answer: before (before/after?)

Flashcard 52: Which base excision repair enzyme is responsible for removing nucleotides at the 3' end?_____

Answer: Lyase

Flashcard 53: What phase of the cell cycle do mismatch base repairs predominantly occur?_____

Answer: S

Flashcard 54: Mechanisms to repair _____ breaks are defective in Ataxia telangiectasia, Fanconi anemia, and SCID

Answer: dsDNA

Flashcard 55: What form of DNA repair fixes mutations due to DNA replication errors?_____

Answer: mismatch repair

Flashcard 56: Non-ionizing radiation causes carcinogenesis by generating _____

Answer: pyrimidine dimers

Flashcard 57: Is homologous recombination error prone?_____

Answer: No

Flashcard 58: 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 59: Polycyclic Aromatic Hydrocarbons (PAH) cause carcinogenesis through their metabolites forming DNA _____

Answer: adducts

Flashcard 60: Slippage in a template strand will cause a(n) _____

Answer: deletion