Mod 8 - DNA mutation Flashcards
two ways mutations can occur
errors in DNA replication (spontanteous mutation)
mutagens
(chemical or environmental agents)
what is base tautomerism
where a tautomer is inserted by accident into the sequence instead of the regular nucleootide
cuz they’re so similar
but the tautomer may cause a diff base to pair with it
what prefix gives normal bases
amino
keto
what prefix references a tautomer
imino
enol
what does imino adenine pair with
C
what does enol-thymine pair with
G
what does enol guanine pair with
T
what does imino cytosine pair with
G
which is the only tautomer that doesnt make a difference
imino-cytosine
what is a base analog
mutagen
base analog replaces normal nucleotide
sometimes can cause a diff nucletoide to base pair with it
so its similar to base tautomerism
what is the important base analog u need to know
5-bromouracil
(5bU)
what can this base analog be used for
to induce mutations in a lab
and in cancer chemotherapy
what is 5bU an analog of
thymine
what are the two types of 5bU
keto-5bU
enol-5bU
which 5bU is not good
enol 5bU
cuz it pairs with G not A
how does a deaminating agent cause mutation
changes structure of nucleotide by getting rid of amine group
whats the only base that cant be deminated
thymine
what are examples of deaminating agents
nitrous acid
sodium bisulphide
what does deamination of adenine give
hypoxanthine
which pairs with C not T
what does deamination of cytosine give
uracil
pairs with A not G duh
what does deamination of guanine give
xanthine
blocks dna replication
what is alkylating agent and give example
adds alkyl group
ethylmethane sulphonate
what is an intercalating agent and give example
inserts itself between base pairs
ethidium bromide
what does UV radiation cause
base dimerisation
what does heat cause
detachment of bases
giving AP sites
