DNA Repair mechanisms Flashcards
what is mutation
an alteration in DNA sequence
classification of mutation
- Point mutation or base substitution
Missense mutation
Nonsense mutation
Silent mutation
which mutation results in new triplet code for different amino acid
missense
which mutation results in triplet code for stop codon (translation terminated prematurely)
nonsense
which mutation results in triplet codes for the same amino acid
silent
what are the type of base substitutions mutation
transitions and tranversion
when pyrimidine replaces pyrimidine or purine replaces purine
transitions
when purine and pyrimidne are interchanged
transversion
what is the name of mutation that results from insertion or deletion of base pair, loss or addition, frame reading translation is altered
Frameshift mutation
somatic mutations occur in which tyoe of cell, are they heritable
occur in any cell except germ cells, are not heritable
Germ-line mutations occur in —–, are —-
gametes, are inherited
autosomal mutation occur within genes on –
autosomes
which mutation arises from normal biological process that alter nitrogenous bases
spontaneous mutation
purine and pyrimidines exist in which form?
tautomeric forms, increasing their chances of mispairing
loops on the newly synthesized strand results in
adding of one nucleotides
loops on temnplate strand results in
omission of one nucleotide
is there need for repair of mistake in DNA polymerase action
no rarely
what happens when a 3’ to 5’ exonuclease activity is attached to DNA polymerase
it chews back to create a base-paired 3’ OH end on the primer strand
Types of DNA damage
- Deamination
- Depurination
- Alkylation
what is the damage called when C»U or A» hypoxanthine
deamination
what is the damage from A or G lost
depurination
guanine oxidizes to 8-oxo-guanine is called
Oxidative damage which causes singel and double strand breaks
intercalating agents cause
indels
which damage cause cancer mutation and thymine dimers
UV lights
