EXAM 4 - Chapter 15, Mutation, DNA Repair, Cancer Flashcards
Mutation are…
permanent and heritable changes to the DNA
Point mutations
changes to nucleotide sequence of individual genes
3 major types of point mutations
substitution, addition, deletion
Chromosomal mutations
changes to the entire gene order on chromosomes
(Substitution Mutations)…
replace one nucleotide with another
when single base is changed, leads to different mRNA and then different protein
There are ___ types of substitution mutations
three
The three types are
- missense (changes one amino acid)
- nonsense (change to a stop codon)
- silent (no affect/change)
(Substitution Mutations) the first mutation missense causes….
one DNA nucleotide to be substituted for another, which means one codon in the resulting RNA will be altered
this will typically alter one amino acid in the resulting protein
(Substitution Mutations) The changes of one amino acid could…
produce little to no effect, or a lethal one
Example of very harmful substitution mutation is…
sickle cell anemia
(Substitution Mutations) The second mutation nonsense is when…
the codon is changed to a stop codon, this would most likely destroy the protein’s function
the earlier in the chain you stop, the worse it is
(Substitution Mutations) the third silent mutation is when…
because or redundancy of the genetic code, that new codon would code for the same amino acid
protein would not be changed and function normally
since there are a few different combos for the same protein, no affect to polypeptide
Addition mutations is when…
add one or more nucleotides to a gene
Deletion mutation is when…
delete one or more nucleotides from a gene
Both deletion and addition result on…
frameshift mutations
Frameshift mutation
shifts the triplet reading frame of the codons
since all codons read in 3’s, so adding just one shifts everything and its messed up
many amino acids after addition will be different, meaning everything is messed up
Mutation outside coding regions…
for the nucleotides can also have effects
mutation on promoter…
may increase or decrease the rate of transcription
mutation at Splice junctions
may alter the ability of the pre-mRNA to be properly spliced
mutation on Intergenic region (space between the genes)
not as likely to have an effect on gene expression
(germ vs somatic) Only mutations in the…
germ line cells will be passed on to individuals of next generation
(germ vs somatic) Mutations in….are not passed on
somatic cells
(germ vs somatic) somatic mutations…
like cancers, can have serious health effects for the individual but ONLY INDIVIDUAL, NOT their children
Mutations can be result of…
natural causes or outside facots
