gene mutations Flashcards
what is addition of bases
an extra base is inserted into the sequence of dna
what effect does it have
frame shift to the right causing the triplets codon to be read in a different order, leading to adifferent amino acid sequence
what is nonsense base deletion
when the bases has been replaced to form a stop codon and polypeptide synthesise ends prematurely
what is inversion of bases
the bases are seperated from the dna strand, reversed and reinserted into the dna
what effect will it have
cause a change in that specific amino acid sequence only will still caus ea change in the tertiary structure
what is duplication of bases
one or more bases repeated causes the frame shift to the right unless three bases are repeated, no frame shift
what is chromosomal mutation
a group of bases become seperated from dna base sequence on one chromosome and inserted into another chromosome or another part
what is the effect
has a significant effect on the phenotype and lead to abnormal phenotype
how do mutations arrise
spontaneously during dna replication
what does spontaneous
naturally occuring not influenced by external factors 1/100000 chance
how does rate increase
mutagenic agents
what does high energy radiation cause
a and b cells and x ray have short wavelength that can distrupt dna structure
what may no2 do
directly interfere with the dna structure and interfere with transcription
what is benzopyrene
a powerful mutagenic factor that inactivates the tumour supressor gene
what does mutation allow
diversity fro natural selection but sometimes can be harmful
