Final: DNA Lesion & Mutation Types Flashcards
what is a damaged DNA site called?
lesion
how many DNA lesions does a cell have/day
10,000
what can DNA lesions lead to?
mutations
failure to fix a lesion
if not fixed before next DNA replication it can lead to a mutation
can a cell recognize a mutation?
no, it can only recognize lesions
what is a DNA mutation
any change in the DNA base sequence
3 types of DNA mutations
point mutation (single base change)
insertion
deletion
what can mutations arise from
copy errors in replication (DNA polymerase)
DNA lesions that cause copy errors
errors in repair of DNA lesions
errors in replication or recombination
types of DNA lesion
nicks, gaps
base dimers
modified bases
AP sites
intercalating agents
base analogues
double strand breaks
what is a nick
broken bond between nucleotides in the backbone of one side in dsDNA
what is a gap
a string of missing nucleotides on one side of dsDNA
what is a base dimer
chemical bond forms btw two adjacent bases
thymine is most common
what is a modified base
any way a base could be chemically changed into something other than A,T,G,C
common base modifications
oxidation
alkylation: methylation/ethylation
AP site
what is an AP site/hole
when a base is completely missing
usually a-purinic site: no G/A
sometimes a-pyrimidinic site: no T/C
