1. The Structure of DNA

2. DNA: The Genetic Material
The instructions for inherited traits are called genes
DNA: primary material that causes recognizable, inheritable characteristics in related groups of organisms

3. Discovering DNA’s Structure
Griffith (1928)
Discovered that harmless bacteria could cause disease when they were mixed with killed disease-causing bacteria
Transformation

4. Discovering DNA’s Structure
Avery (1940’s)
DNA is responsible for transformation in bacteria

5. Discovering DNA’s Structure
Hershey & Chase (1950’s)
Showed that DNA, not protein, is the genetic material in viruses

6. Discovering DNA’s Structure
Chargaff (1949) showed the base pairs of DNA
Adenine with Thymine
Cytosine with Guanine

7. Discovering DNA’s Structure
Rosalind Franklin and Maurice Wilkins (1950’s) used x-ray diffraction to determine the structure of DNA
Images suggested DNA resembled a tightly coiled helix composed of two chains of nucleotides

8. Discovering DNA’s Structure
Watson and Crick (1950’s) constructed a 3D model of DNA
Using information from past experiments determined the DNA was a double helix
Won Nobel Prize in 1962

9. The Shape of DNA A DNA molecule looks like a spiral staircase
Composed of two parallel strands of linked subunits called nucleotides

10. The Shape of DNA
A nucleotide has 3 parts: phosphate group, sugar (deoxyribose), and a base
The phosphate and sugar link together to form the back bone
The bases pair together to connect the two strands

11. Base Pairs