1. Scientists who Identified DNA
Ch 8-1
Scientists who Identified DNA
Griffith
experimented with mice and bacteria
showed that hereditary material can pass from one bacterial cell to another
transfer of genetic material from one cell to another cell is called transformation

2. Griffith’s Discovery of Transformation

3. Scientists who Identified DNA
Avery
experimented with bacteria
showed that DNA is the hereditary material that transfers information between bacterial cells

4. Scientists who Identified DNA
Hershey and Chase
experimented with bacteriophages (viruses that infect bacteria)
confirmed that DNA, and not protein, is the hereditary material

5. The Hershey-Chase Experiment

6. Ch 8-2
DNA 3-D Model
Watson and Crick created a model of DNA by using Franklin’s and Wilkins’s DNA diffraction X-rays
Double Helix
Two strands of DNA
Like a twisted ladder
DNA is a polymer made up of nucleotide monomers

7. DNA Nucleotides 3 Parts Phosphate Group 1 phosphorous with 4 oxygen
Deoxyribose
Ring shaped sugar with 5 carbons
Nitrogen-containing Base
Single or double ring with nitrogen and carbon
4 Types

8. Structure of a Nucleotide

9. Four Nitrogenous Bases
adenine (A)
Double ring
guanine (G)
cytosine (C)
Single ring
thymine (T)

10. Bonds Hold DNA Together
Nucleotides along each DNA strand are linked by covalent bonds
Complementary nitrogenous bases are bonded by hydrogen bonds
G bonds with C
A bonds with T