6.1 DNA and the Code of Life Pages

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. image: taringa.netimage: biologysemester58.wikispaces.com

Alfred Hershey and Martha Chase showed that viruses needed only to inject their DNA into a bacteria to produce more viruses. Image: osulibrary.orst.edu

Phoebus Levene 1920’s DNA was composed of:  A pentose sugar (cyclic, 5-carbon sugar)  A nitogenous base  A phospate group, PO 4 3-

5 Carbon sugar Deoxyribose has one less oxygen atom than ribose. Image: mun.ca

Phosphate group PO 4 3- image: m2c3.com

Nitrogenous Bases Adenine, guanine, cytosine, thymine Image: faculty.ccbcmd.edu

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. image: dnareplication.info

Rosalin Franklin 1951 X-ray crystallography: x-rays were aimed at a crystal of DNA to produce a diffraction pattern. Image: cwp.library.ucla.eduimage: shellemsbioblog.blogspot.com

James Watson and Francis Crick 1953 DNA model Image: chemheritage.org

Complimentary base pairing Image: dedunn.edublogs.org