L6 DNA Repair Flashcards

1
Q

What damages DNA

A

thermal degradation, metabolic byproducts, environmental substances, radiation

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2
Q

What DNA vulnerable to

A

oxidative damage, hydrolytic attack, photolytic conversion

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3
Q

What does failure in DNA repair cause

A

mutation

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4
Q

Example of transition mutation

A

deamination

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5
Q

What mutation is more likely - transition or transversion

A

transition

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6
Q

Why is transition more likely

A

involves substituting a double ring for double ring

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7
Q

Transitions are less likely to result in what

A

amino acid substitution

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8
Q

What do frameshift mutations generate

A

missense proteins

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9
Q

Effect of UV light on DNA

A

induces formation of pyrimidine dimers

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10
Q

How is depurination resolved

A

BER pathway

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11
Q

Example of frameshift mutation

A

depurination

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12
Q

How does the BER pathway identify errors

A

base flipping strategy

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13
Q

What do pyrimidine dimers involve

A

excision of short patches of ssDNA

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14
Q

What can replicate highly damaged DNA

A

trans-lesional DNA polymerase

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15
Q

What can trans-lesional DNA polymerases cause

A

base substitution and single nucleotide deletion mutations

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16
Q

What do trans-lesional DNA polymerases lack

A

precision template recognition, exo-nucleolytic proof reading activity

17
Q

What is very hazardous for a cell

A

double strand breaks

18
Q

What causes double strand breaks

A

ionising radiation, replication errors, oxygen radicals

19
Q

Why are double strand breaks so hazardous

A

no template strand to facilitate repair

20
Q

What mechanisms exist to repair double strand breaks

A

homologous recombination, non-homologous end joining

21
Q

What does non-homologous end joining require

A

function of DNA-PK and ATM proteins kinases

22
Q

Human diseases from faulty DNA repair

A

Lynch syndrome, Cockayne syndrome, cancer,

23
Q

What can faulty DNA repair cause

A

UV sensivity