2007-2008 ap biology chapter 17 mutations: point, frameshift and examples
Post on 05-Jan-2016
217 Views
Preview:
TRANSCRIPT
AP Biology
When do mutations
affect the nextgeneration?
Mutations Point mutations
single base change base-pair
substitution silent mutation
no amino acid change redundancy in code
(wobble effect) missense
change amino acid nonsense
change to stop codon
AP Biology
Sickle cell anemia Primarily African Population
recessive inheritance pattern strikes 1 out of 400 African Americans
Link to Animation Link to Discussion on abnormal fiber formation (valine hydroph.)
AP Biology
Mutations Frameshift
shift in the reading frame
changes everything “downstream”
insertions adding base(s)
deletions losing base(s)
Where would this mutation cause the most change:
beginning or end of gene?
AP Biology
Cystic fibrosis Primarily caucasions of European descent
strikes 1 in 2500 births 1 in 25 whites is a carrier (Aa)
normal allele codes for a membrane protein that transports Cl- across cell membrane
defective or absent channels limit transport of Cl- (& H2O) across cell membrane
thicker & stickier mucus coats around cells mucus build-up in the pancreas, lungs, digestive tract &
causes bacterial infections without treatment children die before 5;
with treatment can live past their late 20s Quick intensive animation (must see) Link to Animated Discussion
AP Biology
Effect on LungsChloride channeltransports chloride through protein channel out of cellOsmotic effects: H2O follows Cl-airway
Cl-
H2O
Cl-
H2O
mucus secreting glands
bacteria & mucus build up
thickened mucus hard to secrete
normal lungs
cystic fibrosis
cells lining lungs
Cl- channel
AP Biology
Notice that after CTT is removed, the AT T joins and still makes the same amino acid (ATC and ATT both are DNA codons for isoleucine, but the PHE is omitted) example of Silent Mutation PLUS DELETION.
Example of Different expressions of codon tables: May have DNA, mRNA or tRNA codons
DNA codons, coding strand, 5’ - 3‘ mRNA codons, 5’ - 3‘
top related