Mutations AP Biology 2007 2008 Mutations n single

Mutations AP Biology 2007 -2008

Mutations n __________ single base change u base-pair substitution u n _________ w no amino acid change w redundancy in code n _________ w change amino acid n _________ w change to stop codon AP Biology When do mutations affect the next generation?

Point mutation leads to Sickle cell anemia What kind of mutation? AP Biology Missense!

Sickle cell anemia n Primarily Africans recessive inheritance pattern u strikes 1 out of 400 African Americans u AP Biology hydrophilic amino acid hydrophobic amino acid

Mutations n __________ u shift in the __________________ n u changes everything “downstream” adding base(s) _________ n AP Biology losing base(s) Where would this mutation cause the most change: beginning or end of gene?

Cystic fibrosis n Primarily whites of European descent u strikes 1 in 2500 births n u normal allele codes for a membrane protein that transports Cl- across cell membrane n n n u AP Biology 1 in 25 whites is a carrier (Aa) defective or absent channels limit transport of Cl- 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 20 s

Chloride channel Effect on Lungs normal lungs airway Cl- transports chloride through protein channel out of cell Osmotic effects: H 2 O follows Cl. Cl- channel H 2 O cells lining lungs cystic fibrosis Cl. H 2 O bacteria & mucus build up thickened mucus hard to secrete AP Biology mucus secreting glands

Deletion leads to Cystic fibrosis delta F 508 loss of one amino acid AP Biology

What’s the value of mutations? AP Biology 2007 -2008