AP Bio DNA/RNA Test review

Miescher

• 1st to Isolate DNA, called it "nuclein"

Levene

• Identified basic components (phosph, sugar, base)

• Discovered deoxyribose

• Proposed Tetranucleotide Model (WRONG)

Griffith

• Griffith’s Principle: a “transforming factor” passes traits

• mice experiment

Avery

• “transforming factor” = DNA

• proved DNA is genetic material

• step-by-step elimination of possibilities w/ centrifuge

Hershey & Chase

• used bacteriophages (virus) & let them infect bacteria

• DNA labeled w/ Phosphorus

• Protein labeled w/ Sulfur

• Only DNA entered bacteria —> protein is not genetic material

Chargaff

• Base pair rules (A to T, G to C) w/ equal % patterns

• Evidence against Levene’s model

• DNA comp. varies by species

Pauling

• Proposed triple-helix model

Franklin

• “The Lady”

• X-Ray images of DNA

• Revealed DNA is helical, 2 strands, uniform width

• Phosphates go OUTSIDE (not inside)

Wilkins

• Franklin’s lab partner

• Data was used as reference by Wat & Crick

Watson

• Used Chargaff’s rules & Franklin’s Data

• C & G form 3 H-bonds, A & T 2

• Double helix model

Crick

• Explained anti-parallel

• Explained DNA replication “Central Dogma”

• Proposed comp. base pairing

Meselson & Stahl

• Tested if DNA replication was conservative, semi-conservative, or dispersive w/ nitrogen isotopes

• Semi-Conservative