DNA repair

Question 1

What causes damage to DNA?

Answer 1

1. environmental factors
2. errors during DNA synthesis

Question 2

Common form of damage:

Chemically damaged, incorrect or missing ___

Answer 2

base

Question 3

Common form of damage:

Longer damaged DNA segements; ___ or ___

Answer 3

deletions or insertions

Question 4

Common form of damage:

____ ____ occur when pyrimidine bases such as T are covalently linked by UV light

Answer 4

pyrimidine dimers

Question 5

Common form of damage:

DNA single strand or double strand ___

Answer 5

breaks

Question 6

Common form of damage:

Covalent __ ___ of strands

Answer 6

cross linking

Question 7

___ is the only molecule that is repaired by the
cell

Answer 7

DNA

Question 8

About ____ bases per cell are lost each day by damage

Answer 8

10,000

Question 9

___ ___ ____ is when DNA corrects errors introduced when DNA is replicated

Answer 9

mismatch repair system

Question 10

___ ___ _____ acts on single bases damaged by oxidation or other chemical modifications

Answer 10

base excision repair

Question 11

_____ ____ ____ repairs large regions of damaged DNA

Answer 11

nucleotide excision repair

Question 12

______ ___-_______ is correcting DNA double strand breaks caused by radiation or when free radicals are repaired

Answer 12

nonhomologous end-joining

Question 13

___ _____ uses homologous recombination to repair double strand breaks that occur ding cell division cycle

Answer 13

recombination repair

Question 14

__ ____ ___ _____ are when chemically modified bases are directly repaired

Answer 14

direct reversal repair systems

Question 15

photolyase, an enzyme that repairs thymine dimers, is an example of what repair mechanism?

Answer 15

direct reversal repair systems

Question 16

to ID the strand with the incorrect base in mismatch repairs, ____ groups are detected as only being on the old strand

Answer 16

methyl

Question 17

the strand ____ the methyl groups in mismatch repair is the new strand

Answer 17

without

Question 18

what 3 enzymes are needed during mismatch repair to remove the incorrect nucleotide and replace it?

Answer 18

endonuclease, exonuclease, DNA polymerase 3, DNA ligase

Question 19

in base excision repair, ___ ____ removes the damaged based by cleaving the glycosidic bone between the base and deoxyribose

Answer 19

DNA glycosylase

Question 20

in base excision repair, an _____ cleaves the backbone to remove the deoxyribose and phosphate group

Answer 20

endonuclease

Question 21

in base excision repair, an _______ removes a number of additional nucleotide residues that are not damaged to create space for DNA polymerase 1 to come in and add a patch of DNA

Answer 21

exonuclease

Question 22

an ____ site is created in base excision repair after cleavage

Answer 22

AP (apurinic, apyrimidinic)

Question 23

in base excision repair, ___ _____ ____ fills in the made gap with a patch of DNA

Answer 23

DNA polymerase 1

Question 24

in base excision repair, __ __ seals the deoxyribose-phosphate backbone to create a continuous strand of DNA

Answer 24

DNA ligase