presentation

1. DNA:
Structure and Function

2. Our understanding of DNA
2
1869
• Discovery of DNA
• F. Miescher
1883
• Chemical basis of
inherited traits
• A. Weismann & K.
Nageli
late 1920s
• "Transformation
Principle"
• F. Griffith
1944
• DNA is the
Genetic Material
• Avery, MacCleod,
McCarty
1950
• DNA really is the
Genetic Material
• Hershey and
Chase
1950
• In DNA samples,
equal quantities
of Adenine and
Thymine while
Guanine equal to
Cytosine
• E. Chargaff
1952
• Photo 51
• R. Franklin
1953
• Double Helix!
• J. Watson & F.
Crick
A=T
C=G
*The only names and dates you have to remember are Franklin, Crick, and
Watson and the year 1953.

3. Figure 7.2
Frederick Griffith
3

4. 4

5. Figure 7.3
5

6. Race to discover the structure of DNA
6
X-ray diffraction

7. Maurice Wilkins and Rosalind Franklin
7

8. Chargaff’s Rule
Erwin Chargaff
8
A=T
C=G

9. James Watson and Francis Crick
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10. 10
Photo 51
By R. Franklin
1953 The Eagle
Pub, Cambridge

11. Double Helix!
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12. Nobel Prize 1962
12
Wilkins Crick Watson

13. Figure 7.5
• Two strands
• Nucleotides
A. Phosphate
B. Deoxyribose sugar
C. Nitrogenous base
1. Adenine
2. Guanine
3. Thymine
4. Cytosine
• Antiparallel orientation
• Complementary Bases
• Purines pair with pyrimidines
• A-T and G-C
13
DNA Structure

14. 14

15. Cell
Nucleus
Chromosome
DNA wrapped
around histone
protein
DNA Gene
DNA Structure within a Chromosome
15

16. Compare and Contrast:
DNA and RNA
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17. The Central Dogma of Gene Expression
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Proposed by Francis Crick 1958

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