1. DNA: The Chemical Nature of the Gene
CHAPTER 10
DNA: The Chemical Nature of the Gene

3. Key characteristics of the genetic material
Store information
Replicate faithfully
Encode the phenotype
- Stable
- Undergo change

4. Early studies of DNA
Nucleus contained material that was slightly acidic and rich in phosphorus
– Miescher called it nuclein; later renamed nucleic acid
DNA contains four nitrogenous bases – adenine, cytosine, guanine, and
thymine
DNA made up of linked repeating units, called nucleotides; each nucleotide
contains a sugar, a phosphate, and a base

5. Chargaff’s rules: in DNA, the amount of adenine is always equal to the amount of thymine (A = T), and the amount of guanine is always equal to
the amount of cytosine (G = C)

6. DNA as the genetic material – evidence from experiments
with bacteria and their viruses

7. Discovery of the transforming
principle
Griffith – 1928
Experiments with
Streptococcus pneumoniae

8. Identification of the transforming
principle
Avery, MacLeod, and McCarty

9. The Hershey-Chase experiment – E. coli and phage T2

12. Structure of DNA – Watson and Crick’s model

14. RNA as genetic material

15. Primary structure of DNA and RNA – sequence of nucleotides
joined together by phosphodiester linkages
Each nucleotide made of a sugar, a phosphate, and a base

19. Secondary structure of DNA
The double helix

24. The central dogma

26. Special structures can form in DNA and RNA
Hairpin

27. Stem

28. Secondary structure of RNA component of RNase P of E. coli