6.1 DNA and the Code of Life

Pages 228-233

nuclein

• A name given to DNA when it was discovered by Friedrich Miescher in 1869.

Joachim Hammerling

performed experiments on Acetabularia to verify that the genetic material was in the nucleus.

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Alfred Hershey and Martha Chase

1952- showed that viruses needed only to inject their DNA into a bacteria to produce more viruses.

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Phoebus Levene

1920’sDNA was composed of: A pentose sugar (cyclic, 5-carbon sugar) A nitogenous base A phospate group, PO4

3-

5 Carbon sugar

• Deoxyribose has one less oxygen atom than ribose.

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Phosphate group

PO43-

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Nitrogenous Bases

• Adenine, guanine, cytosine, thymine

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Erwin Chargaff

1940The amount of Adenine, A, is equal to the amount of Thymine, T.

The amount of Guanine, G, is equal to the amount of Cytosine, C.

Nucleotide

• DNA has a negative charge because of the phosphate ions in its backbone.

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Rosalin Franklin

1951 X-ray crystallography: x-rays were aimed at a crystal of DNA to produce a diffraction pattern.

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James Watson and Francis Crick

• 1953 DNA model

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Complimentary base pairing

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