histonic experiments on the discovery of dna

meischer qt

what are nuclei made of

meischer exp

white blood cells, broke down cytoplasm w pepsin. once nucleus was isolated, he analyzed its molecular composition

meischer discovery

nucleus is made of a new molecule (dna) c, h, n, o, + p

Griffith qt

what makes bacteria harmful

griffith exp

injected mice w various combos of lethal and nonlethal bacteria: nonlethal=lived, lethal=died, killed lethal=lived killed lethal+nonlethal=dead

griffith discovery

molecule was transferred from the killed lethal to the nonlethal that caused the nonlethal to become harmful

griffith conclusions - what is it known as today?

• bacterial transformation

• bacteria picked up dna from environment,

• providing genetic info for new traits

hershey-chase qt

is protein or dna responsible for producing viruses by taking over a cell’s metabolic machinery?

hershey-chase exp

used radioactive sulfur & phosphorus to trace proteins and dna to see which reprogrammed bacteria to make viruses

sulfur traced protein, phosphorus traced dna

hershey-chase discovery

dna, not protein, was responsible, so dna is genetic material

chargaff qt

how does the base composition of dna vary in diff organisms, what are the ratios of the nucleotide bases (a, t, c, and g)?

chargaff exp

dna was extracted from diff species and hydrolyzed to break apart nucleotides and analyze them chemically

chargaff discovery

1. dna varies in diff species

2. equal amounts of a&t and c&g

• a bonds w/ t and c bonds w/ g

franklin qt

what is the structure of dna

franklin exp

used water to isolate dna strands then used an x-ray to take pics of it. then she calculated dist. between atoms

watson-crick qt

what is the structure of dna

watson-crick exp

built a model of dna using other scientists’ experimental results

watson-crick discovery

dna’s double helix shape, realized that dna replication occurs