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.

Alfred Hershey and Martha Chase 1952- showed that viruses needed only to inject their DNA into a bacteria to produce more viruses

Phoebus Levene 1920’s DNA was composed of: A pentose sugar (cyclic, 5-carbon sugar) A nitogenous base A phospate group, PO43-

5 Carbon sugar Deoxyribose has one less oxygen atom than ribose.

Phosphate group PO43-

Nitrogenous Bases Adenine, guanine, cytosine, thymine

Erwin Chargaff 1940 The 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.

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

James Watson and Francis Crick 1953 DNA model

Complimentary base pairing