Exam 4- Chapter 10 Flashcards
Point mutations
alteration of a single pair of nucleotides
insertions
slippage in new strand causes addition of a base
shifts reading frame
Deletion
slippage in parent strand removes a base
shifts reading frame
Tpes of induced mutations
base analogs
DNA modifying agents
Intercalating agents
chemicla mutagens
Physical mutagens
base analogs
structurally similar to normal bases
mistakes occur when they are incorporated into polynucleotide chain
DNA modifying agent
alter a base causing it to mispair
Chemical mutagens
chemicals induce mutations at a higher rate than found spontaneously
Intercalating agents
distort DNA to induce single nucleotide pair insertions and deletions
Physical mutagens
Ultraviolet light can cause a higher than expected mutation in DNA by forming thymine dimers
Wild-type
most prevalent form of a gene
Forward mutation
wild type to mutant form
- wildtype is most prevalent
Reversion mutation
mutant phenotype to wild-type phenotype
Suppressor mutation
An additional mutation occurs somewhere in a sequence, not where the original mutation is, and suppresses the effects of the original
Same side reversion
codon is mutated and codes for different amino acid but another mutation happens in same spot and reverses effects
Silent mutation
change base sequence of codon but not encoded amino acid
affects of silent mutation
The mutation is present but results in the same amino acid
Missense mutation
single base substitution that changes a codon for one amino acid into another
Impact of missense- similar properties
small impact
impact of missense- different properties
large impact
polar to non-polar AA could completely unfold
Nonsense mutation
converts sense codon into a stop codon
Impact is dependent on
location
Impact of early nonsense mutation
huge impact on structure and function
Impact of nonsense mutation at end of sequence
little impact
Frameshift mutation
results from insertion or deletion of one or two base pairs in coding region of gene
