I. History of DNA
A. Friedrich Miescher
1. Identified DNA in the nucleus of white blood cells in 1871
2. It was a sugary, phosphate-rich chemical which he called
nuclein
B. Fredrick Griffith- The Transformation Experiment- 1928
1. British bacteriologist whose focus was on the
epidemiology and pathology of bacterial pneumonia
2. His experimentation is now known as the transformation
experiment
3. He showed that Streptococcus pneumoniae, could
transform from one strain into a different strain
4. The transforming principle was later identified as DNA
C. Oswald Avery- DNA is the Genetic Material- 1944
1. The genetic information was thought to be contained in protein
2. Continuing the research done by Griffith in 1928, Avery worked with
MacLeod and McCarty on the mystery of the transformation
3. His team made protein and DNA extracts of the capsulted strain (which
has a smooth surface) and introduced the substance into a rough-surfaced
type of bacterium
4. The rough-surfaced strain transformed into the smooth-surfaced type, he
knew the substance he had extracted contained the gene that coded for
the smooth surface
5. Avery published the results of his research in 1944. The paper led to more
intensive studies of DNA, which eventually revealed it to be the common
agent of heredity
D. Alfred Hershey and Martha Chase
1. “Waring Blender” Experiment
2. DNA is the Genetic Material- 1952
Food Blender
Centrifuge
32
DNA
P Labeled
35
Protein S Labeled
E. Erwin Chargaff – 1940’s
1. Chargaff's rules
a. The amount of guanine is equal to cytosine and the amount of
adenine is equal to thymine
b. The composition of DNA varies from one species to another, in
particular in the relative amounts of A, G, T, and C bases
F. Discovery of the Structure of DNA
1. James Watson and Francis Crick- 1953
a. Cambridge University
2. Maurice Wilkins and Rosalind Franklin
a. Kings College
Photo 51
The Watson and Crick Model of the Structure of DNA
II. DNA Structure
A. Double Helix
B. DNA Nucleotide
C. Base Pairing
D. Purine and Pyrimidine Bases
E. Antiparallel Nature of DNA
F. DNA Replication
G. Messelson and Stahl
1. DNA Replicates Semi-conservatively
2. Let E. coli replicate its DNA in Nitrogen- 15 for several generations
III. RNA Characteristics
A. RNA Nucleotide
B. Types of RNA
1. Messenger RNA
2. Transfer RNA
3. Ribosomal RNA
C. Transcription
D. RNA Processing in Eukaryotes
E. The Genetic Code: mRNA codons
IV. Translation of the Genetic Code
A. Protein Synthesis
Polysomes
V. Mutations to the DNA Molecule
Missense
Nonsense
Frameshift Mutation
VI. The Operon Model of Gene Expression
A. The Lac Operon