mutations and DNA repair Flashcards
in the following sequence of DNA, the italicized base has been mutated. What type of mutation is this?
5’- GATCTCCGAATT-3’
5’GATCTCCCAATT-3’
transvehrsion-changed pyrimidine to purine or vice versa
mutations that occur naturally as a result of natural processes are called
spontaneous mutations- result from abnormalities in cellular/biological processes
which class(es) of mutations can or do change the amino acid sequence of proteins but NEVER truncate them?
missense mutation- alter amino acid sequence
if a codon is mutated from AAA to AAg what type of mutation has occurred?
silent mutations- alter codon but does not change amino acid encoded
if a codon is mutated from UAU and UAA what type of mutation has occurred?
non-sense mutation- change codon into stop codon
a temporary change in structure of a nitrogenous base is called
a tautomeric shift-spontaneous changes in base structure can cause mutations if they occur immediately prior to DNA replication
what is the Ames tea used to determine
the mutagenicity of chemical compounds
which type of DNA repair mechanism is most important TO HUMANS in regard to removing and replacing pyrimidine dimer induced by UV light?
nucleotide excision repair- repairs thymine dimers and chromosome modification bases
one of the most frequent trinucleotide repeats involved expansion of which of the following?
A.GAA
B. CAG
C. ATg
D. any Condon containing three of the same bases
CAG
mutation
change in DNA sequence
transition
change in pyrimidine (C,T) to another pyrimidine or a purine (A,G) to another purine
(same base changes)
transversion
change in a pyrimidine to a purine or vice versa
missense mutations
alter the amino acid structure, change in codon
nonsense mutation
changes codon into a stop codon
silent mutations
alter codon but do not change the amino acid encoded
