DNA Repair Self-Help Exam

Instructions: You may answer as many or as few questions as you wish, in any order, and you may take the test as often as you wish. When you are ready to check your performance, scroll to the bottom of this document and click the "Submit the Exam" button. All questions you answered will be graded, and your score will be shown at the bottom of the exam.

There is a total of 25 questions. Good Luck!

1) How many genes participate in DNA repair, even in organisms with the smallest genomes?

a) 1 to 5
b) 10 to 30
c) 60-90
d) 100-200
e) 1000-2000

2) Is there an -OH group at an AP site?

a) Yes
b) No

3) Aside from being a result of hereditary defects in proteins involved in DNA repair, what else do XP and HNPCC have in common?

a) Both are defects in gap-filling polymerases.
b) Both increase cancer risk.
c) Both are defects in base excision repair.
d) Both are defects in nucleotide excision repair.
e) Both are defects in mismatch repair.

4) Which of the following binds to methyl groups?

a) MutH
b) MutL
c) MutS

5) DNA deoxyribophosphodiesterases hydrolyze

a) deoxyribose.
b) deoxyribose-3'-phosphate linkages in DNA.
c) the deoxyribose-3'-phosphate linkage adjacent to a 5'-terminal deoxyribose phosphate residue in DNA.
d) deoxyribose-5'-phosphate linkages in DNA.
e) the deoxyribose-5'-phosphate linkage adjacent to a 3'-terminal deoxyribose phosphate residue in DNA.

6) Which of the following uses energy, originally derived from light, to convert pyrimidine dimers to pyrimidine monomers?

a) MTHF
b) 8-HDF
c) FADH^-
d) rhodopsin
e) chlorophyll

7) Which of the following proteins is important for non-homologous end joining in Saccharomyces cerevisiae?

a) RAD50
b) RAD51
c) RAD52

8) What is the most common type of spontaneous damage to DNA?

a) Depyrimidination
b) Methylation
c) Replication errors
d) Deamination
e) Depurination

9) What are the most common types of photoproducts resulting from the interaction of UV light with DNA?

a) Inter-strand cross links
b) cyclobutane pyrimidine dimers
c) (6-4) pyrimidine dimers
d) AP sites

10) Which of the following proteins is involved in initial recognition of
base mismatches?

a) XPA
b) MLH1
c) MSH2
d) ERCC1
e)PMS2

11) To which type of cancer do defects in mismatch repair most frequently contribute?

a) Lung
b) Breast
c) Skin
d) Colon

12) Which of the following is not recognized and excised by a DNA N-glycosylase?

a) Thymine glycol
b) 3-Methyl adenine
c) Uracil
d) 5-Methyl cytosine
e) Cytosine

13) Which mammalian DNA polymerase is responsible for filling in the 1-nucleotide gaps generated during base excision repair?

a) Alpha
b) Beta
c) Gamma
d) Delta
e) Epsilon

14) Which of the following proteins is a helicase?

a) XPA
b) XPB
c) XPC
d) RPA
e) NBS1

15) Is the following sentence true or false? Ku can bind to closed circular plasmid DNA.

a) True
b) False

16) Which of the following proteins is not involved in both transcription and DNA repair?

a) XPA
b) XBP
c) CSA
d) CSB
e) XPD

17) Which of the following proteins contributes to structure-specific nuclease activity?

a) XPB
b) XPC
c) XPD
d) XPE
e) XPF

18) Patients suffering from which of the following genetic diseases have brittle hair?

a) Xeroderma pigmentosum
b) Cockayne's syndrome
c) Trichothiodystrophy

19) How many OH groups are there in thymine glycol?

a) 1
b) 2
c) 3
d) 4

20) Which of the following is a known in vivo substrate of DNA-PK?

a) Ku70
b) Ku80
c) Ligase IV
d) Artemis
e) The in vivo substrates of DNA-PK have not yet been clearly identified

21) Which is more abundant?

a) Rad50 monomers
b) Rad50 dimers
c) Rad50 trimers

22) Which of the following is not an advantageous result of damage bypass?

a) The damage is removed from the DNA
b) DNA replication can proceed
c) Sister chromatids are generated that can be used for homologous repair

23) The DNA replication taking place during synthesis-dependent strand annealing is

a) dispersive.
b) semi-conservative.
c) conservative.

24) Which of the following proteins is not involved in recognition of DNA damage?

a) XPC
b) RNA polymerase
c) PCNA
d) Uracil DNA glycosylase
e) HR23B

25) What is required for successful ligation?

a) 5'-OH adjacent to 3'-OH
b) 5'-phosphate adjacent to 3'-phosphate
c) 5'-phosphate adjacent to 3'-OH
d) 5'-OH adjacent to 3'-phosphate