L6 DNA Repair Flashcards Preview

BMS242 Cell & Molecular > L6 DNA Repair > Flashcards

Flashcards in L6 DNA Repair Deck (23)
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1

What damages DNA

thermal degradation, metabolic byproducts, environmental substances, radiation

2

What DNA vulnerable to

oxidative damage, hydrolytic attack, photolytic conversion

3

What does failure in DNA repair cause

mutation

4

Example of transition mutation

deamination

5

What mutation is more likely - transition or transversion

transition

6

Why is transition more likely

involves substituting a double ring for double ring

7

Transitions are less likely to result in what

amino acid substitution

8

What do frameshift mutations generate

missense proteins

9

Effect of UV light on DNA

induces formation of pyrimidine dimers

10

How is depurination resolved

BER pathway

11

Example of frameshift mutation

depurination

12

How does the BER pathway identify errors

base flipping strategy

13

What do pyrimidine dimers involve

excision of short patches of ssDNA

14

What can replicate highly damaged DNA

trans-lesional DNA polymerase

15

What can trans-lesional DNA polymerases cause

base substitution and single nucleotide deletion mutations

16

What do trans-lesional DNA polymerases lack

precision template recognition, exo-nucleolytic proof reading activity

17

What is very hazardous for a cell

double strand breaks

18

What causes double strand breaks

ionising radiation, replication errors, oxygen radicals

19

Why are double strand breaks so hazardous

no template strand to facilitate repair

20

What mechanisms exist to repair double strand breaks

homologous recombination, non-homologous end joining

21

What does non-homologous end joining require

function of DNA-PK and ATM proteins kinases

22

Human diseases from faulty DNA repair

Lynch syndrome, Cockayne syndrome, cancer,

23

What can faulty DNA repair cause

UV sensivity