Mutations Point mutations single base change basepair substitution
Mutations Point mutations single base change base-pair substitution silent mutation no amino acid change redundancy in code missense change amino acid nonsense change to stop codon Where would this mutation cause the most change: beginning or end of gene?
Point mutation leads to Sickle cell anemia What kind of mutation? hydrophilic amino acid hydrophobic amino acid
Mutations Frameshift in the reading frame insertions changes everything “downstream” adding base(s) deletions losing base(s)
Cystic fibrosis normal allele codes for a membrane protein that transports Cl- across cell membrane Chloride channel transports chloride through protein channel out of cell Osmotic effects: H 2 O follows Clnormal lungs airway Clcells lining lungs H 2 O
In people with cystic fibrosis, non-working cystic fibrosis proteins mean no salt (chloride) enters the air space and water doesn't either. Because of less diffusion of salt and less osmosis of water, the mucus layer is concentrated and very sticky. Cl- channel airway Cl- H 2 O cells lining lungs cystic fibrosis bacteria & mucus build up H 2 O normal lungs thickened mucus hard to secrete mucus secreting glands
Deletion leads to Cystic fibrosis without treatment children die before 5; with treatment can live past their late 20 s delta F 508 loss of one amino acid
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