DNA

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Central Dogma of Biology
DNA
RNA
Protein
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avirulent
virulent

avirulent
virulent
Frederick Griffith, 1928
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T2 Bacteriophage
A bacteriophage infects and reproduces inside a
bacterial cell Bacteriophages contain only DNA
and proteins.
A.D. Hershey and Martha Chase, 1952
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P
S
A.D. Hershey and Martha Chase, 1952
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Chemical nature of the transforming material

• Resistant to organic solvent and proteases -- it
  is not a protein
• Resistant to ribonuclease -- it is not an RNA
  molecule
• Sensitive to deoxyribonuclease -- it is likely a
  DNA molecule

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DNA
1869, Friedrich Miescher discovered in the cell
nucleus a mixture of compounds --
nuclein. Nuclein contains deoxyribonucleic acid
(DNA).
At the end of 19th century Chemists learned the
structure of DNA and a related compound,
ribonucleic acid (RNA)
Both long polymers of nucleotides.
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A nucleotide is composed of a sugar, a phosphate
and a base
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The chemical nature of DNA and RNA
DNA
RNA
Adenine (A) Cytosine C Guanine (G) Thymine (T)
Adenine (A) Cytosine C Guanine (G) Uracil
(U)
Sugar deoxyribose
Sugar ribose
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nucleosides
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nucleotides
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3
5
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5 TCA 3
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