Mutations Mutation a change in DNA not all mutations are harmful can happen in body cells and in gametes mutations are passed down to offspring only when they are in the ID: 931534
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Slide1
Notes on Mutations
A change in DNA
Slide2Mutations
Mutation
: a
change
in DNA
-not all mutations are harmful -can happen in body cells and in gametes. **mutations are passed down to offspring only when they are in the gametes **
Types of MutationsSubstitution: one base is substituted for another ACTTAGGC ACATAGGCInsertion: a base is added ACTTAGGC ACTTAGGCTDeletion: a base is removed ACTTAGGC ACTTAGG__
Slide3Mutagens:
factors in the environment that
cause mutations
Ex
: x-rays, UV light, radiation, chemicals, smoking, sun ta
Slide4Mutations
Mutations are changes in DNA sequenceschanges to the order of A, T, C & Gdifferent order = different amino acid in protein
different protein structure = different protein function
Bb
bb
BB
Slide5Mutations
Point mutations
single base change
silent mutation
no amino acid change
redundancy in codemissensechange amino acidnonsensechange to stop codon
Slide6Point mutation leads to Sickle cell anemia
What kind of mutation?
Missense
!
Slide7Sickle cell anemia
Primarily Africans
recessive inheritance pattern
strikes 1 out of
400
African Americans
Slide8Mutations
Frameshift
shift in the
reading frame
changes everything “downstream”insertionsadding base(s)deletionslosing base(s)Where would this mutation cause the most change:beginning or end of gene?
Slide9THERAATANDTHECATATETHEREDBAT
THE
RAA
TAN
DTH
ECATATETHEREDBATFrameshift mutations
THERATANDTHECATATETHEREDBAT
THERTANDTHECATATETHEREDBATTHERATANDTHECATATETHEREDBAT
THE
RTA
NDT
HEC
ATA
TET
HER
EDB
AT
Deletion
Insertion
Slide10Cystic fibrosis
Primarily whites of European descent
strikes 1 in
2500
births1 in 25 whites is a carrier (Aa)normal allele codes for a membrane protein
that moves Cl- across cell membranemutant channel limit movement of Cl- (& H2O) across cell membranethicker & stickier mucus coats cells mucus build-up in the pancreas, lungs, digestive tract & causes bacterial infectionswithout treatment children die before 5; with treatment can live past their late 20s
Slide11