Tuesday, Jan. 12 A Day
• Wednesday 8AM sharp meet in Stuber Gym
• Sharpened Pencils, ID & Calculator
• ACT Science Advice
• Questions over experiments?
• Quiz: DNA Structure
• Notes- History of DNA
Discovery of DNA
A Brief History
Friedrich Meisher 1871
• Used old wound wrappings
to take pus samples
• From the samples, he
isolated and extracted DNA
• Experiment documented
gone unnoticed for many
years
Phoebus Levene 1910
• Determined that DNA
contains 3 parts:
• nitrogenous bases (adenine,
thymine, guanine and cytosine)
• Phosphate
• Deoxyribose Sugar
Erwin Chargaff 1949
Erwin Chargaff 1949
• Determined that the amounts of A=T and the
amounts of G=C
• Discovered complementary base pairing
• Did not respect Watson and Crick as scientists
Rosalind Franklin 1950s
• X- ray diffraction to
determine double
helix structure of
DNA
• Calculated the
dimensions of a
DNA molecule
Maurice Wilkins
• Worked with Rosalind
Franklin
• Showed Francis Crick and
James Watson the x- ray
diffraction of DNA
• DID NOT GAIN
PERMISSION from
Franklin
Watson and Crick 1953
• Used information from
Levene, Chargaff and
Franklin (among others)
• Built a model of the
structure of DNA
• Wrote a paper regarding
their findings
• Made hypothesis for DNA
replication
Protein (Histones)